Journal of Lignocellulose Technology

Transcription

1 J. Lignocellulose Technol. Journal of Lignocellulose Technology Vol. 2, No. 1, December 2017 Lignocellulose Lignocellulose Lignocellulose ISSN (printed) : ISSN (online) : Lignocellulose Published by : Research Center for Biomaterials Indonesian Institute of Sciences Lignocellulose Lignocellulose

2 Volume 2, Number 1 December 2017 TABLE OF CONTENT The utilization of citric acid as an environmentally friendly of chemical modification agent of lignocellulosic materials: a review Sukma S. Kusumah, Lilik Astari, Subyakto, Ragil Widyorini, Zhongyuan Zhao Chemicals distribution of empty fruit bunch (EFB) degradation in super-critical organic solvents Rakhman Sarwono, Saepulloh, Brayen, Eka Dian Pusfitasari, Yeyen Maryani Characterization of acetylated cellulose from oil palm frond fiber (Elaeis guineensis Jacq.) for composites application Wida B. Kusumaningrum, Firda Aulya Syamani, Diaz Desiana, Lisman Suryanegara, Subyakto Bioactivity of liquid smoke of rice husk against Spodoptera exigua Arief Heru Prianto, Fifi Alami Fahlawati, Dede Sukandar Characteristics of composite film from polyvinyl alcohol reinforced by bleached pulp of oil palm frond and agar powder of Gracillaria sp. Firda Aulya Syamani Peningkatan mutu kayu dan kualitas kayu konstruksi dengan teknik pengasapan : kajian sifat kimia kayu dan keawetan terhadap jamur Schizophyllum commune Fries Lolyta Sisillia, Farah Diba, Vitus Andri Forlius, Cristoporus Gita Piana Characterization palm kernel caked and its application in making board composite Miranti Maya Sylvani, Nanda Andrian Yuditya Bioaktivitas ekstrak Taxus sumatrana Yeni Aprianis, Eka Novriyanti, Hilwan Yuda Teruna Potency of Trametes versicolor U97 for degrading lindane in liquid medium Ajeng Arum Sari, Ummu Hanifah, Kazutaka Itoh

3 INTRODUCTION Abbreviation: J. Lignocellulose Technol. A peer-reviewed journal dedicated to foster the science and technology in lignocellulosic materials Home: Description J. Lignocellulose Technol. is published both printed (ISSN: ) and online (ISSN: ). Focus and Scope Focus: The focus of this journal is related to lignocellulosic material including crops residue. J. Lignocellulose Technol. encourage manuscripts reporting unique, innovative contributions to the physics, biology, biochemistry, chemistry, material science and applied mechanics aspects of lignocellulosic material, including wood and other biomass resources. J. Lignocellulose Technol. is a peer-reviewed journal which publishes original articles and review articles. All submitted papers will be reviewed by at least two referees. Scope: Advance in the science and technology of utilization of lignocellulosic materials obtained from wood, crop residues and other materials containing cellulose, lignin, and related biomaterials. Emphasis is placed on bioproducts, bioenergy, papermaking technology, new manufacturing materials, composite structures, and chemicals derived from lignocellulosic biomass. Lignocellulose modification, biorefinery derived from lignocellulose, biodegradation related to lignocellulose materials, wood or lignocellulose preservatives, lignocellulose conversion and plant technology Editor in Chief: Dr. Dede Heri Yuli Yanto Editorial Board: Prof. Dr. Sulaeman Yusuf Prof. Dr. Subyakto Dr. Wahyu Dwianto Dr. Euis Hermiati Dr. Widya Fatriasari Dr. Titik Kartika Dr. Firda Aulya Syamani Dr. Riksfardini Annisa Ermawar Dr. Lisman Suryanegara Dr. Apri Heri Iswanto Dr. Tati Karliati Dr. Yenny Meliana Editorial Staff: Apriwi Zulfitri Anis Sri Lestari Lillik Astari Fahriya Puspita Sari Ni Putu Ratna Ayu Krishanti Secretariat: Eka Lestari Photographer: Agus Mulyadi Graphic Design: Adik Bahanawan Eko Widodo Website: Faizatul Falah Ismadi Febrina Dwiky Indriyani Fathul Bari Herry Samsi Syam Budi Iryanto Bramantyo Wikantyoso Publisher & Secretariat: Research Center for Biomaterials Indonesian Institutes of Sciences Jl. Raya Bogor KM 46, (CSC BG) Cibinong Science Center Botanical Garden, Cibinong, 16911, Bogor, Indonesia j.lignotech@biomaterial.lipi.go.id Subscription: Free journal subscription and free hardcopy (postal fee applied)

4 FOREWORD The term lignocellulose refers to material composed of lignin, cellulose and hemicellulose. Lignocellulosic material is a constituent component of plant cell walls and often found in biomass or waste derived from agricultural products, forests and plantations. Composition of lignocellulose in plant varies and depends on the type of biomass, age and the environment where the plant grows. Generally, plant contains15-25% of lignin, 40-50% of cellulose, 25-30% of hemicellulose and 5-10% of extractive and ash (USDE, 2015). Indonesia is a tropical country which rich in lignocellulosic materials. Most of lignocellulosic based-products, such as pulp, paper, furniture and building materials are derived from the natural forest. The exploitation of timber from forest has been increased from time to time along with the increased number of population and demand of the products. The over-exploitation of natural forests can lead to forest destruction and worse to natural disasters such as floods, droughts and land slide. In order to fulfill the continuing demand for raw materials in wood industries, Industrial Plantation Forest (Hutan Tanaman Industri or HTI) is one of the solutions to maintain the preservation of natural forest. However, it may challenge sustainability of other species or biodiversity because of its monoculture system. Other solution is generating valuable products from lesser known fast-growing wood species, industrial lignocellulosic biomass waste, or non-wood lignocellulosic commodities such as bamboo, sisal, kenaf which can be harvested in a relatively short periods of time (2-3 years). Developing technology and materials engineering are of importance to improve durability and physical-mechanical properties of fast-growing wood with low quality. Similarly, fabricating wood substitute materials from forestry industry waste, plantation, agriculture and other natural fibers for building construction materials, furniture, automotive parts and other meaningsis equally critical. In this issue, Journal of Lignocellulose Technology contains eight original articles and one review article that have been selected and peer-reviewed to be published in volume 2, We hope this publication is useful for the advancement of science and technology in the related fields. Dr. Dede Heri Yuli Yanto Editor in Chief

5 Acknowledgement Editorial board would like to acknowledge persons and parties below for their great assistance and valuable support: Dr. Dieni Mansur Research Center for Chemistry, LIPI Dr. Gustini Syahbirin Department of Chemistry, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University Lukmanul Hakim Zaini, M.Si Department of Forest Products, Faculty of Forestry, Bogor Agricultural University Nanang Masruchin, Ph.D Kyung Pook National University, South Korea Ade Andriani, Ph.D Research Center for Biotechnology, LIPI Dr. Achmad Solikhin Department of Forest Products, Faculty of Forestry, Bogor Agricultural University Dr. Iwan Risnasari Department of Forestry, University of North Sumatera Didi Tarmadi, Ph.D RISH - Kyoto University, Japan Ikhsan Guswenrivo, Ph.D RISH - Kyoto University, Japan Arif Nuryawan, PhD Department of Forestry, University of North Sumatera Dr. Apri Heri Iswanto Department of Forestry, University of North Sumatera Lilik Astari, M.ForEcosys.Sc Research Center for Biomaterials, LIPI

6 J. Lignocellulose Technol. 02 (2017), 1-7 Journal of Lignocellulose Technology Journal homepage: Review The utilization of citric acid as an environmentally friendly of chemical modification agent of the lignocellulosic materials: a review Sukma S. Kusumah 1*, Lilik Astari 1, Subyakto 1, Ragil Widyorini 2, Zhongyuan Zhao 3 1 Research Center for Biomaterial, Indonesian Institute of Sciences (LIPI), Jl. Bogor KM 46 Cibinong Bogor 1691, Indonesia 2 Faculty of Forestry, Universitas Gajah Mada (UGM), Bulaksumur, Caturtunggal, Kec. Depok, Kabupaten Sleman, Daerah Istimewa Yogyakarta 55281, Indonesia 3 College of furnishings and industrial design, Nanjing Forestry University, 159 Longpan Rd, Xuanwu Qu, Nanjing Shi, Jiangsu Sheng , China * Corresponding author: sukma.surya@biomaterial.lipi.go.id Received: 11 April Received in revised form: 29 July Accepted: 30 October Published online: 29 December 2017 Abstract The environmental issues demand the development of environmentally friendly chemical substances for the modification of lignocellulosic materials. Citric acid is known as a non-toxic chemical substance that obtained from the natural resources such as citrus fruits. Commonly, citric acid is used in the preparation of many industrial products. Nowadays, citric acid as a polycarboxylic acid is the promising alternative raw material to replace the harmful synthetic chemical agents in many applications with lignocellulose material such as cotton fabric production, wood preservation, an adhesive of wood-based products, starch films, super absorbent. Reactivity of carboxylic groups of citric acid and hydroxyl groups of lignocellulose materials leads to improve the properties of products from lignocellulose materials. Keywords : Carboxylic groups, citric acid, environmentally friendly, hydroxyl groups, lignocellulose material Introduction Nowadays, citric acid become the prime organic acid produced abundantly by fermentation. Business Communications Co. (BCC) in a recent study of fermentation chemical markets estimated that the global production of citric acid in 2004 was about 1.4 million tonnes (Soccol et al. 2006). 1 Citric acid is commonly used to impart a pleasant, tart flavour to foods and beverages. It also finds applications as a function of additive detergents, pharmaceuticals, cosmetics and toiletries. Utilization of citric acid in U.S. was about 64 % for foods and beverages, 22 % for detergents and cleaning products and 10 % for pharmaceutical and nutritional products, bout 2 % went into cosmetics and toiletries (Soccol et al. 2006). The large

7 number of citric acid caused the increasing of citric acid production constantly. Production history of citric acid In 1893, citric acid fermentation was firstly observed by Wehmer using a culture of Penicillium glaucum on sugar medium (Soccol et al. 2006). A few years later, two new fungal strains was isolated with the ability to accumulate citric acid, that were designated Citromyces (Penicillium). However, the contamination and long duration were main problems that caused the industrial trials failed. In 1916, Currie found that numerous strains of Aspergillus niger produced significant amounts of citric acid. The greatest finding was that A. niger grew well at ph values around and high concentrations of sugars favour citric acid production (Soccol et al. 2006). The first citric acid fermentations were attempted in surface cultures. In the 1930s, some units were embedded in England, in Soviet Union, and in Germany for the commercial production. Commercially, submerged microbial fermentation of molasses was used in the production of citric acid; the main source of citric acid worldwide is Aspergillus niger in the the fermentation process (Pallares et al., 1996). The better successes of synthesize citric acid were achieved using microbial fermentations, and over the period of time, this technique has become the method of ultimate choice for its commercial production over chemical synthesis (Mattey, 1992). However, the introduction of submerged fermentation had several problems, including the choice of productive strains with low sensitivity to trace elements (Hossain et al., 1984). The consideration of raw material much more carefully is necessary. The optimization of the conditions for the utilization of cheap material like sugar cane molasses, beet molasses, starch and hydrolysate starch were carried out (Sarangbin et al., 1999). Utilization history of citric acid Awareness to the ecofriendly materials lead to research that reveal new green materials for several purposes such as adhesive for panels. Several research has been conducted to seek an alternative for panel adhesive in order to reduce formaldehyde emissions. Citric acid, an organic acid generated from citrus has been 2 reported as natural adhesive for woodbased molding and panel industry. Umemura et al. (2012a) reported that fabricated wood-based molding bonded with citric acid has high water resistance and good resistance to boiling water. Moreover, Umemura et al. (2012b) showed that the molding bonded with citric acid reached good bending properties with the specific MOR (Modulus of Rupture) and MOE (Modulus of Elasticity) values under the optimum condition of 20 wt% citric acid content were 18.1 MPa and 4.9 GPa, respectively. Furthermore, Umemura et al. (2013 and 2014) mentioned that a mixture of citric acid and sucrose can be used as a natural adhesive for particleboard. They reported that the particleboard obtained higher MOR, internal bonding strength (IB), and lower thickness swelling than the requirement of 18 type of JIS A 5908 (2003) for particleboard. Liao, Liao et al. (2016) conducted research on development of particleboard using citric acid as adhesive, the results show that addition of citric acid and sucrose enhance the properties of low density particleboards. Those board properties reported fulfilled the Chinese national forestry industry standard LY/T It is also reported that the particleboard performed good thermal insulation, therefore the board can be utilized as green building material. Widyorini et al. (2016a) and (2016b) reported that citric acid significantly improve the mechanical properties and dimensional stability of particleboard made from bamboo and teak wood, respectively. In further study, Widyorini et al. (2017) reported that the adding Maranta and Canna starches in resin improved mechanical properties of particleboard. The board produced satisfied the JIS standard A 5908 for particleboard. Analysis using FTIR showed that the more citric acid content the higher presence of ester groups. Kusumah et al. (2016) reported that utilization of citric acid up to 20 wt% in particleboard made from sweet sorghum bagasse performs superior physical properties and comparable to those particleboard using phenol formaldehyde (PF) and polymeric 4,4 -methylenediphenyl isocyanate (pmdi) adhesive. In another study of Zhao et al. (2016) about the development of the new adhesive from tannin and sucrose, citric acid has been used as additive. They discovered that the

8 addition of citric acid promote the reaction between tannin and sucrose at a lower temperature than only used tannin and sucrose. They reported also that the mechanical properties and water resistance of the particleboard were enhanced. Another study by Subyakto et al. (2015) shown that addition of sucrose on citric acid enhanced particleboard properties made from oil palm frond particles. In addition, citric acid also proven as natural waterproofing for wood. Investigation by Amirou, Pizzi and Delmotte (2016) reported that citric acid able to enhance water resistance on welded joint of spruce. It is mentioned that the addition of 10-12% citric acid improves mechanical properties and water resistance of welded spruce. Feng et al. (2014) mentioned that the treatment of poplar wood using citric acid perform a significant improvement of dimensional stability and radial compression strength, but it causes a reduction in the MOR and impact strength. The wood modification using citric acid also beneficial for its dimensional stability as reported by He et al. (2015). They conducted modification of poplar wood (Populus adenopada Maxim) using glucose with addition of citric acid or 1,3- dimethylol-4,5-dihydroxy ethyleneurea (DM) as cross-linker agents. Hasan et al. (2007) reported that the citric acid has a role as representative of polycarboxylic acids. Impregnation process was conducted as a modification procedure with 7.0% water dilution of citric acid. FTIR was occupied to monitoring the contribution of citric acid ester linkages. The results show that chemical modification using citric acid perform a tendency towards enhancement of wood durability and this method promote an environmentally friendly method. The effect of citric acid on biological durability against termite and decay of wood (Hasan et al., 2007) and particleboard (Kusumah et al., 2017b). They investigated the citric acid effective enhanced the biological durability of pine (Pinus sylvestris L.) particularly on its sapwood (Hasan et al., 2007) and particleboard (Kusumah et al., 2017b). Another important chemical modification using citric acid is its role as an absorbent. Chemical modification using citric acid as absorbent reported by Thanh & Nhung (2009), they found that cellulose that modified with citric acid on reaction temperature 120 C for 12 h able to absorp 3 Pb 2+ and Cd 2+ ion. This result shows that citric acid and cellulose can be modified as a metal absorbance. Modification of citric acid for absorbent also reported by Chiou et al. (2012), the research reported that reaction of wheat gluten and citric acid result in superabsorbent materials that can absorbed up to 78 times of their weight in deionized water. Furthermore, Monroy- Figuerora et al. (2015) found that Byrsonima crassifolia (BC) after chemical modification process with citric acid can be used as heavy metal (Cd 2+ and Ni 2+ ) removal from water. It is reported that an increment in the oxygenated functional groups on the BC surface caused by the treatment using acid. Altun and Pelivan (2012) mentioned that chemical modification using citric acid is more beneficial to react with lignocellulosic materials compare to other modification agents due to it can improves the sorption properties as well as enhance the mechanical strength of the biomass because of the cross-linking. Another report of chemical modification using citric acid that resulted in presence of carboxylic sites is presented by Leyva-Ramos et al. (2012). They mentioned that modification of natural corncob with citric acid solution enhance the adsorbing capacity of Cadmium(II) from water solution. The capacity of adsorption was increased by the increment of citric acid concentration up to 1M but the ability decreased for citric acid concentration above 1M. In another study, Reddy and Yang (2010) discovered that citric acid can crosslink starch and enhanced the tensile strength, thermal stability and decreased the dissolution of starch films in water and formic acid. The study mentioned also that the cross-link starch used citric acid had some benefit for starch film industry such as cheaper than the current starch crossliking methods and environmentally friendly. In further study, Reddy et al. (2012) reported that cross-linking with citric acid improved the dry and wet strengths of the film without affecting the water vapor permeability. Babu et al. (2015) reported also that citric acid can be used as an effective chemical modification agent of sweet potato starch for preparation of an acid thinned starch that play important role as a fat mimetic in real food system. They concluded that the citric acid treatments lead increase in apparent amylose content, a visible degradation was

9 observed when the granules were subjected to citric acid treatment with no significant change in granule size. Sridach et al. (2013) studied also the effect of citric acid on the properties of cross-linked poly(vinyl alcohol)/ starch adhesives. They reported that the adhesive strength effectively improved when using citric acid as a catalyst in the cross-linking reaction due to the structure of cross-linked starch adhesive with a citric acid catalyst cured in a cross-linked structure. In addition, citric acid has been used as cross-linker in the development of wheat straw hemicellulose films (Azeredo et al., 2015). They concluded that the citric acid effective decreased the water solubility and water vapor permeability, and also as a plasticizer. Characteristics of citric acid Citric acid is an alpha-hydroxy acid that has three carboxylic acid groups (COOH), and one hydroxyl group (OH). Citric acid can be found in odorless and colorless crystals with an acidic taste. The solid has density of 1.66 g/ml, melting point of 153 C and boiling point of 175 C (Barbooti and Al-Sammerrai, 1986). It is highly soluble in water to give an acidic, sour tasting solution (Barbooti and Al- Sammerrai, 1986). Citric acid is a weak organic acid. It is a tribasic acid, as it has three COOH groups that can react with three base molecules (Abou-Zeid et al., 1984 and Tsao et al., 1999). It commonly exists as anhydrous (water-free) form or as a monohydrate (with one molecule of water) (Kim, 2010). The monohydrate can be converted to the anhydrous form when it is heated to about 78 C (Barbooti and Al- Sammerrai, 1986). When heated to temperatures above 175 C, it decomposes with loss of carbon dioxide (Barbooti and Al-Sammerrai, 1986). Citric acid readily forms citrate complexes with metallic cations (Kim, 2010). Lignocellulose and citric acid as raw materials Lignocellulose is a material which composed of cellulose, hemicellulose, lignin, extractives. Those chemical compounds have OH groups that can react with COOH groups. Considering the reaction of OH groups and COOH groups, many previous study utilized citric acid in the development of products which used lignocellulose as raw material such as plant 4 fiber (Ghosh et al., 1995), paper (Yang et al., 1996), cotton fabric production (Yang et al., 1997), wood products (Vukusic et al., 2006), adhesive of wood-based products (Umemura et al., 2012), starch films (Reddy and Yang, 2010), super absorbent (Thanh and Nhung, 2009), bio-based elastomer (Tran et al., 2009). The properties of the fibers such as thermal stability, thickness swelling, mechanical properties were enhances by using citric acid as chemical substances in the development of the products from the lignocellulose fibers. Mechanism reaction of citric acid as a chemical modification agent of lignocellulose products Umemura et al. (2012a and 2012b) mentioned in their study that some component except for tannin contributed to the bondability which improved the bending properties and water resistance of the molding. They judged that the ester linkage in the wood-based molding were detected by fourier transform infrared spectroscopy (FTIR) which indicated that the reaction occurred between hydroxyl groups of wood and carboxyl groups of citric acid. Analysis using FTIR revealed that citric acid responsible to the formation of hydrogen bonding and esterification (C-O- C), this bonding contributes to the enhancement of particleboard properties (Liao et al., 2016). Figure 1. The reaction between citric acid and cellulose molecule (Liao et al., 2016) Widyorini et al. (2016a, 2016b, 2017), and Kusumah et al. (2016, 2017a, 2017b) analyzed the FTIR in their study that the presence of ester linkages indicate a reaction of carboxyl groups from citric acid and hydroxyl groups from bagasse were occur. Those reactions result in good physical properties of the board. In addition, Zhao et al. (2016) mentioned that

10 ester linkages and dimethylene ether bridges were observed by FTIR. Catalytic effect resulted by citric acid during wood welding was by chemical modification on lignin structure, cellulose and hemicellulose (Amirou, Pizzi and Delmotte 2016). The results show that glucose is well penetrated on wood cell walls and catalytic reaction with hydroxyl groups were occur (He et al., 2015). Wood treatment with glucose and cross-linker agents (citric acid or 1,3-dimethylol-4,5- dihydroxy ethyleneurea/dm) can bulk the cell walls which leads to a dimensional stability. Citric acid for cross-linker agent is more environmentally friendly yet less efficient compared to DM (He et al., 2015). FTIR revealed that reaction of citric acid and subsequent neutralization with sodium hydroxide resulted in attachment of carboxylate group on gluten chains (Thanh & Nhung, 2009; Chiou et al., 2012). The use of citric acid to improve performance properties of cellulosic has been reported by Yang et al. (1991, 1996, 1997) and Yang & Wang (1996). It mentioned that citric acid is non-toxic and inexpensive polycarboxylic acid that able to improve cellulosic properties through crosslinking. In order to the cotton and wool fabrics product, the presence of polycarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid, citric acid, or polyacrylic acid contributed for the chemical reaction of the grafting of cyclodextrins onto cotton or wool fabrics (Martel et al., 2001). Marte et al. (2001) reported also that the polycarboxylic acid play the role of linking agent through an esterification reaction with the OH groups of both cyclodextrins and cotton (or wool) fibers. Chung et al. (1998) mentioned that citric acid is expected to react with hydroxyl groups in cellulose and chitosan or with amino groups in chitosan to form ester cross-linking or an inter-ionic attraction. This reaction is useful as durable press and antimicrobial finishing agents for cotton. Despite of, citric acid is less effective in cross-linking than 1,2,3,4- Butanetetracarboxylic acid but is cheaper and can be used as an extender in cotton product (Welch, 1992). The fusion of carboxylic acid groups into hemicellulose through reaction with citric acid followed by cross-linking with chitosan effective improve the properties relative to hemicellulose, chitosan, a cellulose sponge 5 product, and hemicellulose citrate alone (Salam et al., 2011). Conclusion The utilization of citric acid as a chemical modification agent of lignocellulose materials has been reviewed from a lot of experimental work. Most of the results in the experimental work showed that the cross-linked and or esterification from carboxyl groups of citric acid and hydroxyl groups of lignocellulose material is the main mechanism of modified lignocellulose material by citric acid in several products. Citric acid has some benfit as a chemical modification agent than existing chemical agent such as cheaper, environmentallhy friendly, and sustainable resources. References Abou-Zeid, A.-Z. A. and Ashy, M.A. (1984). Production of citric acid: A review. Agric. Wastes, 9, pp Altun T. and Pehlivan, E. (2012). Removal of Cr(VI) from aqueous solutions by modified walnut shells. Food Chem., 132, pp Amirou, S., Pizzi, A. and Delmotte, L. (2016). Citric acid as waterproofng additive in butt joints linear wood welding. Eur. J. Wood Prod. Azeredo, H. M.C., Vrettou, C.K., Moates, G.K., Wellner, N., Cross, K., Pereira, P. H. F., and Waldron, K.W. (2015). Wheat straw hemicellulose films as affected by citric acid. Food Hydrocoll., 50, pp Babu, A. S., Parimalavalli, R., Rudra, S.G. (2015). Effect of citric acid concentration and hydrolysis time on physicochemical properties of sweet potato starches. Int. J. Bio. Macromol., 80, pp Barbooti, M. M., and Al-Sammerrai, D. A. (1986). Thermal decomposition of citric acid. Thermochim Acta, 98, pp Bautista, L.F., Sanz, R., Carmen, M.M., Gonzalez, N. and Sanchez, D. (2009). Effect of different non-ionic surfactants on the biodegradation of PAHs by diverse aerobic bacteria. International Biodeterioration & Biodegradation, 63(7), pp Chiou, B., Jafri, H., Cao, T., Robertson, H., Gregorski, K.S. Imam, S.H., Glenn, G.M. and Orts, W.J. (2013). Modification of wheat gluten with citric acid to produce superabsorbent materials. Journal of Applied Polymer Science.

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12 sucrose as adhesives. Proceedings of the International Conference on Innovation in Polymer Science and Technology (IPST 2013), pp Thanh, N.D. and Nhung, H.L. (2009). Cellulose modified with citric acid and its absorption of Pb2+ and Cd2+ ions. The 13rd International Electronic Conference on Synthetic Organic Chemistry (ECSOC-13), 1-3 November Tran, R.T., Zhang, Y., Gyawali, D., and Yang, J. (2009). Recent development on citric acid derived biodegradable elastomer. Recent plants Biomed Eng., 2, pp Umemura, K., Ueda T., and Kawai, S. (2012a). Characterization of wood-based molding bonded with citric acid. J. Wood Sci., 58, pp Umemura, K., Ueda T., Munawar, S.S., and Kawai, S. (2012b). Aplication of citric acid as natural adhesive for wood. J. Appl. Poly. Sci. 123, pp Umemura, K., Sugihara O., and Kawai, S. (2013). Investigation of a new natural adhesive composed of citric acid and sucrose for particleboard. J. Wood Sci., 59, pp Umemura, K., Sugihara O., and Kawai, S. (2015). Investigation of a new natural adhesive composed of citric acid and sucrose for particleboard II: effects of board density and pressing temperature. J. Wood Sci., 61, pp Vukusic, S.B., Katovic, D., Schramm, C., Trajkovic, J., and Sefe, B. (2006). Polycarboxylic acids as non-formaldehyde anti-swelling agents for wood. Holzforschung, 60, pp Welch, C. M. (1992). Formaldehyde-free durable press finishes. Rev. Prog. Color. Relat. Top., 22, pp Widyorini, R., Umemura, K., Isnan, R., Putra, D.R, Awaludin, A. and Prayitno, T.A. (2016a). Manufacture and properties of citric acid-bonded particleboard made from bamboo materials. Eur. J. Wood Prod., 74, pp Widyorini, R., Nugraha, P. A., Rahman, M. Z. A., and Prayitno, T.A. (2016b). Bonding ability of a new adhesive composed of citric acidsucrose for particleboard. BioResources., 11(2), pp Widyorini, R., Umemura, K., Kusumaningtyas, A.R., and Prayitno, T.A. (2017). Effect of starch addition on properties of citric acid bonded particleboard made from bamboo. BioResources., 12(4), pp Yang, C. Q. and Andrews B.A.K. (1991). Infrared spectroscopic studies of the nonformaldehyde durable press fnishing of cotton fabrics by use of polycarboxylic acids. Journal of Applied Polymer Science, 43, pp Yang, C. Q., Yang, Y., Wang, X. and Li, S.J. Formaldehyde-free zein fber-preparation and investigation. Journal of Applied Polymer Science, 59, pp Yang, X. Wang, X. and I. Kang. (1997). Ester cross-linking of cotton fabric by polymeric carboxylic acids and citric acid. Textile Research Journal 67(5), pp Yang, C. Q. and Wang, X. (1996). Formation of cyclic anhydride intermediates and esterifcation of cotton cellulose by multifunctional carboxylic acids: An infrared spectroscopy study. Textile Research Journal, 66 (9), pp Zhao, Z., Umemura, K., and Kanayama, K Effects of the addition of citric acid on tannin-sucrose adhesive and physical properties of the particleboard. BioResources, 11(1), pp

13 J. Lignocellulose Technol. 02 (2017), 8-17 Journal of Lignocellulose Technology Journal homepage: Article Chemicals distribution of empty fruit bunch (EFB) degradation in super-critical organic solvents Rakhman Sarwono 1 *, Saepulloh 2, Brayen 2, Eka Dian Pusfitasari 1, Yeyen Maryani 2 1 Research Centre for Chemistry Indonesian Institute of Sciences, Kompleks PUSPIPTEK Serpong, Tangsel (15314), Indonesia 2 University of Sultan Ageng Tirtayasa, Jl. Jend. Sudirman Km 3, Cilegon, Banten (42435), Indonesia * Corresponding author:rach14@lipi.go.id Received: 11 April Received in revised form: 29 July Accepted: 30 October Published online: 29 December 2017 Abstract Hydrothermal liquefaction (HTL) of empty fruit bunch (EFB) of palm oil in different organic solvents (methanol, ethanol, acetone, toluene and hexane) to produce bio-oil were comparatively investigated. Experiments were carried out in an autoclave at different temperature of 300, 350 and 400 o C with a fixed solid/liquid ratio of 4 gram in 50 ml solvent, without catalysts and reaction time of 5 hours. The liquid products were analyzed using GCMS to determine the chemical composition. The chemical compositions were greatly affected by the solvent types. Each solvent has a major component in bio-oil product. Methanol and ethanol solvents resulted the ketones/others were the major compounds. Toluene and hexane solvents resulted the organic acids were the major compound, favored with the increasing the temperature. While acetone solvent resulted favored amount between esters and organic acids. Temperature operation resulted more varies in the chemical composition and the precentages of the bio-oil. Keywords : EFB, liquefaction, bio-oil, composition Introduction Biomass can be converted into smaller molecules in the grade of fuels using thermo-chemical processes. Cellulose molecules are bound to each other by interand intra-molecular hydrogen linkages through their hydroxyl groups, and crystalline cellulose is difficult to decompose. Direct liquefaction of biomass in sub- and super-critical solvents (water, alcohols, and phenol) has proven to be an effective approach to convert lignocelluloses materials into low molecular weight chemicals (Wang, Xu and Leitch, 2009). The knowledge about thermal characteristics and decomposition mechanism of biomass is considerably important for optimization of the conversion process and efficient utilization of the liquid 8

14 products (Liu, Feng and Sun 2011a,b). Currently, liquefaction is used by many researchers for utilization biomass because of its advantages, such as (1) the presence of solvent dilutes the concentration of the products, decreasing the apportunity for cross-linked reactions and reverse reactions, and (2) the relatively low temperature in comparison to pyrolysis (El-barbary and Shukry, 2008; Chen and Lu, 2009). Solvents have a remarkable effect on the liquefaction reaction. Some articles have reported that the liquefaction of biomass in the presence of organic solvents were effectively lowers the viscosity of heavy oil derived from biomass liquefaction (Demirbaş, 2000). Although solvents have shown obvious reactive activity in many work, it is still unclear how solvents affect the biomass liquefaction process. Liquefaction of biomass with proper solvents is a benign process that can prospectively be integrated with optimized conditions to produce fuel and valuable chemicals (Liu and Zhang, 2008). The role of the solvent is usually to fragment the biomass and stabilize the fragmented products to ensure maximum production of bio-oil. The better solvent is at stabilizing the fragments, the higher the oil yield and the lower the solid biochar fraction (Akhtar and Amin, 2011). It follows that solvents tend to increase the fragmentation of the biomass and disrupts the stability of the reaction mixture should increase the solid biochar yield.typical properties of organic solvents as shown in Table 1. Table 1. The properties of organic solvents Organic P critical T critical, Dielectric solvent (atm) a o K a o C constant b Methanol (25 o C) Ethanol (25 o C) Acetone (25 o C) Toluene (25 o C) n-hexane (20 o C) a Smith and Van Ness,1959 b Anon1 It is expected that low dielectric constant of the solvent would increase to dissolve the biomass fragmented products, that will increase the liquefaction process. Solvent polarities can be classified into three categories: polar protic, dipolar aprotic and non-polar solvents. Polar protic solvents such as water and alcohols refer to compounds with a hydrogen atom attached to an electronegative atom like oxygen. Dipolar protic solvents such as acetone and 1,4-dioxane describe a molecule that does not contain an O-H bond. All solvents in this class contain a bond with a large bond dipole, which is a multiple bond between carbon and either oxygen or nitrogen. Nonpolar solvents are compounds that have low dielectric constants and are not miscible with water such as benzene and diethyl ether (Mazaheri et al., 2010). Non-polar solvents have low dielectric constants (< 5) and are not good solvents for charged species such as as anions and dipolar aprotic solvents have dielectric constant between 5 and 20. They have intermediate polarity, they are good solvents for a wide range of reactions. Polar protic solvents tend to have high dielectric constant and high dipole moments. These solvents all have large dielectric constants (> 20), They possess O-H or N-H bonds, they can also participate in hydrogen bonding (James, 2012). Recently, organics solvents such as ethanol, methanol, acetone etc., have been utilized as the reaction medium instead of water to enhance the yield of biooil with low oxygen content (Liu and Zhang, 2008; Zhou et al., 2012; Chen et al., 2012). The basic reaction mechanisms of biomass liquefaction can be described: (i) depolimerization of the biomass; (ii) decomposition of the biomass monomers by cleavage, dehydration, decarboxylation and deamination; (iii) recombination of the reactive fragments through condensation, cyclization, and polymerization to form new compounds (Huang et al., 2011). In the first step cellulose is converted into glucose, hemi-cellulose into xylose, and lignin into polyols (Wettstein et al., 2012). The reaction in an organic medium strongly depend on the interactions between the solvents and the substrates. If the liquefaction solvents is a product derivable of biomass itself, such as phenol, alcohol or polyalcohol, the conversion of biomass can be enhanced (Behrendt et al., 2008). 9

15 The degradation of biomass cannot be described by detailed chemical reaction pathways with well-defined single reaction steps. The reason is that biomass is a combination of cellulose, hemicelluloses, and lignin, and these components interact each other, leading to very complex chemistry (Kruse and Gawlik, 2003). The analysis of complex reactions which occur in the liquefaction of biomass, is important to the description of the reactions behavior and to the optimization of the operating conditions. The main object of this paper is to study the effect of various organic solvents and temperatures in the bio-oil chemical compositions. Materials and Methods Palm oil empty fruit bunch (EFB) was provided from the oil palm industry. The EFB was dried and grinded into smaller particle of - 80 mesh. The EFB compose of cellulose 44.21%, hemicellulose 16.68%, and lignin 35.51% (Sarwono et al., 2014). All chemical of solvents are analytical reagent grade provided by Merck. Experimental procedures Liquefaction experiments were carried out in a reactor of 60 ml stainless steel cylindrical. 4 gram of EFB with -80 mesh particle size contained into the reactor, organic solvent of 50 ml was added and then the reactor was sealed properly and make sure that there is no leakage. The reactor was mounted into the furnace that the temperature can be set in certain point as the reacting temperature desired. The reactor leave for several hours as the reacting time. After reacting time was reached the reactor was pull out and poured with tap water to chill and stop the reaction until at ambient temperature, and then the reactor valve was open to leave the gas out, and then the reactor was opened properly to pull out the reaction products. The solid and liquid products are separated by filtering. The solid was rinsed with same solvent and dried at 105 o C until the weight remained unchanged as solid product. The liquid was analysis by GC-MS. The liquid was evaporated in vacuum evaporator to measure the soluble products. Separation procedure After the reaction time was reached the reactor pulled out from the furnace, and then poured with tap water until the temperature in room temperature. The gas inside was vented out. The liquid and solid was filtered, the solid was washed with the same solvent, until the liquid was cleared. The solid was dried at 105 o C overnight, and then quantified until the weight is unchanged (carbon fraction). The liquids were evaporated under vacuum evaporator overnight until the weight is unchanged (bio-oil). Yield of bio-oil = Yield of carbon = Mass of bio oil mass of EFB Mass of carbon mass of EFB x100% (1) x100% (2) Conversion rate = 100 wt% - yield of carbon (3) Products analysis The gas produced was leaf out not to be analyzed. The soluble liquid products were analyzed using GC-MS, Agilent technologies 7890B, with DB5 Column (30 m x 0.32 mm x 0.25 µm, detector MSD 5977A, Helium (He) was used for mobile phase or carrier gas with flow rate 1 ml/min. Injector temperature was 250 o C. The temperature of ion source and MS Quadruple were 230 o C and 150 o C, respectively. Fifteen bio-oil samples were obtained in different liquefaction solvents (methanol, ethanol, acetone, toluene, and hexane) at the temperature of 300 o C, 350 o C and 400 o C were analyzed, respectively. Extracted bio-oil from solvent of methanol, ethanol, acetone were diluted with acetone until the end of volume 4 ml aliquot. Extracted biooil from solvent of toluene and hexane were diluted with hexane until the end of volume of 4 ml aliquot, respectively. Results and Discussions The results of experiment were shown in Table 2-7. The effects of organic solvents and temperatures were examined. Biomass was firstly decomposed and depolymerized to smaller fragments or lighter molecules during the liquefaction process. Those unstable fragments rearranged through condensation, cyclization and polymerization to form new compounds (Huang et al., 2011). In general, the higher the reaction temperature, it,s easier to defragment of the polymers into a liquid oil- 10

16 rich phase. A further increase the reaction temperature leads to enhance decomposition of these fragments into gaseous. The effect of organic solvents resulted different rate of conversion, carbon residue and soluble liquid and the variation of the fragment chemical compositions (Sarwono, Pusfitasari and Ghozali, 2016). In general, the higher reaction temperatures are the higher the final pressures of the liquefaction process. The elevating pressure will further result in the increase of the density of liquefaction solvents (Mazaheri et al., 2010). Chemical composition of bio-oil The bio-oil products from liquefaction of EFB were characterized by GC-MS to identify of their chemical composition. Typical composition of bio-oil as shown in Table 2 to 6. There are a great results that any solvent type has a major component in bio-oil product. The decomposition of EFB biomass using methanol solvent resulted the highest precentages is 2-pentanone, 4-hydroxy-4- methyl with molecule carbon of 6 that is the lower molecule in that bio-oil (Table 2). By increasing the temperature the precentages of 2-pentanone, 4-hydroxy-4- methyl also different, at temperature reaction of 300 o C the percentage of 2- pentanone, 4-hydroxy-4-methyl is about 57.43%, at temperature of 350 o C the precentage of 2-pentanone, 4-hydroxy-4- methyl is about 69.19%, that the highest percentages. At temperature of 400 o C the percentage of 2-pentanone, 4-hydroxy-4- methyl is about 61.33%, that is slightly lower compared with the result of 350 o C. The second higher component is hexadecanoic acid, methyl ester. Increase the temperature increase the percentage of hexadecanoic acid, methyl ester. At temperature 300 o C the percentage of hexadecanoic acid, methyl ester is about 10.18%, at temperature 350 o C the percentage of hexadecanoic acid, methyl ester is about of 13.17% and at temperature 400 o C the percentage of hexadecanoic acid, methyl ester is about 19.52%. The third higher component is octadecanoic acid, methyl ester. Increase the temperature is also increase the percentage of octadecanoic acid, methyl ester. At temperature 300 o C the octadecanoic acid, methyl ester = 5.43%, at temperature 350 o C octadecanoic acid, methyl ester = 6.89% and at temperature 400 o C the octadecanoic acid, methyl ester = 9.83%. Table 2. Chemical composition of bio-oil obtained in methanol solvent at different temperature. Retention Compounds name (Formula) Temperature ( o C) time (RT) % area % area % area pentanone, 4-hydroxy-4-methyl (C6H12O2) Dodecanoic acid, methyl ester (C13H26O2) Dodecanoic acid (C12H24O2) Dodecanoic acid, ethyl ester (C14H28O2) Methyl tetradecanoate (C15H30O2) Tetradecanoic acid, ethyl ester (C16H32O2) Hexadecanoic acid, methyl ester (C17H34O2) Hexadecanoic acid (C16H32O2) Hexadecanoic acid, ethyl ester (C18H36O2) Octadecanoic acid, methyl ester (C19H38O2) Ethyl oleate (C20H38O2) Octadecanoic acid, ethyl ester (C20H40O2) Cis-10-nonadecenoic acid, methyl ester (C20H38O2) Octadecanoic acid, 10-oxo-, methyl ester (C19H36O3) Eicosanoic acid, methyl ester (C21H42O2) Total Another amazing phenomena is hexadecanoic acid, ethyl ester, at temperature 300 o C the percentage of hexadecanoic acid, ethyl ester is about 8.78 %, by increasing the temperature the precentage of hexadecanoic acid, ethyl ester is decrease drastically. At temperature 350 o C the percentages of hexadecanoic acid, ethyl ester is about 0.99%, and at 400 o C is about 1.54%. It s meant that by increasing the temperature hexadecanoic acid, ethyl ester was converted into another fragments. The component of dodecanoic acid is similar 11

17 to the hexadecanoic acid, ethyl ester, by increasing the temperature the percentage is also decrease drastically. At temperature of 300 o C, the percentage of dodecanoic aicd is about 8.22 %, at 350 o C the percentage is about 6.17%, and at 400 o C the percentage is about 0.07%. At 400 o C the major component of dodecanoic acid was converted into another substances. The highest component resulted from the degradation of EFB biomass with the solvent of ethanol is 2- pentanone, 4-hydroxy-4-methyl. At the temperature reaction of 300 o C gave percentage of 2-pentanone, 4-hydroxy-4- methyl is about %. At temperature reaction of 350 o C the percentage of 2- pentanone, 4-hydroxy-4-methyl is about 91.67% and at temperature of 400 o C gave the lower component of 2-pentanone, 4-hydroxy-4-methyl, is about 54.75% (Table 3). The second higher component is hexadecanoic acid, ethyl ester. At temperature of 300 o C the percentage of hexadecanoic acid, ethyl ester is about %, at 350 o C the percentage of hexadecanoic acid, ethyl ester is about 4.05%, and at temperature of 400 o C the percentage of hexadecanoic acid, ethyl ester is about 25.36%. The third higher component is n- hexadecanoic acid. At temperature of 300 o C the percentage of n-hexadecanoic acid is about %, at 350 o C the percentage of n-hexadecanoic acid is about 0.99%, and at temperature of 400 o C the percentage of n-hexadecanoic acid is about 2.51%. By increasing the temperature alot of n-hexadecanoic acid was converted into another substances. The higher component resulted from the degradation of EFB biomass with solvent of acetone is n-hexadecanoic acid. At the temperature reaction of 300 o C the percentage of n-hexadecanoic acid about %. At temperature reaction of 300 oc the percentage of n-hexadecanoic acid is about 48.34%, and at temperature of 400 o C the percentage of n-hexadecanoic acid is about % (Table 4). It s meant that the degradation of biomass in ethanol solvent resulted the highest component is n-hexadecanoic acid. The second higher component is hexadecanoic acid, ethyl ester. At temperature of 300 o C the percentage of hexadecanoic acid, ethyl ester is about %, at 350 o C the percentage of hexadecanoic acid, ethyl ester is about %, and at temperature of 400 o C the percentage of hexadecanoic acid, ethyl ester is about %. The third higher component is 2- pentanone,4-hydroxy-4-methyl at temperature of 300 o C the percentage of 2- pentanone,4-hydroxy-4-methyl is about %, at 350 o C the percentage of 2- pentanone,4-hydroxy-4-methyl is about %, and at temperature of 400 o C the percentage of 2-pentanone,4- hydroxy-4-methyl is about 5.85 %. At the temperature of 400 o C a lot of 2- pentanone,4-hydroxy-4-methyl was converted into another substances. Retention time (RT) Table 3. Chemical composition of bio-oil obtained in ethanol solvent. Compounds name (Formula) 12 Temperature ( o C) % area % area % area Pentanone,4-hydroxy-4-methyl- (C6H12O2) Dodecanoic acid (C12H24O2) Dodecanoic acid, ethyl ester (C14H28O2) Tetradecanoic acid (C14H28O2) Tetradecanoic acid, ethyl ester (C16H32O2) Hexadecanoic acid, methyl ester (C18H36O2) n-hexadecanoic acid (C16H32O2) Hexadecanoic acid, ethyl ester (C18H36O2) Ethyl Oleate (C20H38O2) Octadecanoic acid, ethyl ester (C20H40O2) Total The fourth higher component is temperature of 400 o C the precentage of dodecanoic acid. At temperature of 300 o C the percentage of dodecanoic acid is about 7.92 %, at 350 o C the precentage of dodecanoic acid is about 6.63 %, and at dodecanoic acid is about 5.90 %. It s meant that dodecanoic acid is just slighly decrease by increasing the temperature.

18 The highest component resulted from the degradation of biomass with solvent of toluene is n-hexadecanoic acid. At the temperature reaction of 300 o C the precentage of n-hexadecanoic acid is about %. At temperature reaction of 350 o C the percentage of n- hexadecanoic acid is about 80.53%, and at temperature of 400 o C the percentage of n-hexadecanoic acid of is about % (Table 5). It s meant that the component of n-hexadecanoic is stand in increasing temperature. The second higher component is dodecanoic acid. At temperature of 300 o C the percentage of dodecanoic acid is about %, at 350 o C the percentage of dodecanoic acid is about %, and at temperature of 400 o C the percentage of dodecanoic acid is about 8.87 %. It s meant that the component of dodecanoic acid is just slighly decrease by increasing the temperature. The third higher component is tetradecanoic acid. At temperature of 300 o C the percentage of tetradecanoic acid is about 6.06 %, at 350 o C the percentage of tetradecanoic acid is about 3.17 %, and at temperature of 400 o C the percentage of tetradecanoic acid is about 2.41 %. It s meant that the component of tetradecanoic acid is just slighly decrease by increasing the temperature. The highest component resulted from the degradation of biomass with solvent of hexane is n-hexadecanoic acid. At the temperature reaction of 300 o C the percentage of n-hexadecanoic acid about %. At temperature reaction of 350 o C the percentage of n-hexadecanoic acid is about 62.53%, and at temperature of 400 o C the percentage of n-hexadecanoic acid of is about % (Table 6). It s meant that the component of n- hexadecanoic is decrease by increasing the temperature. Especially at temperature of 400 o C, the component of n- hexadecanoic acid was decreased darstically. Table 4. Chemical composition of bio-oil obtained in acetone solvent. Retention Compounds name (Formula) Temperature ( o C) time (RT) % area % area % area pentanone, 4-hydroxy-4-methyl (C6H12O2) Dodecanoic acid (C12H24O2) Dodecanoic acid, ethyl ester (C14H28O2) Tetradecanoic acid, ethyl ester (C16H32O2) Hexadecanoic acid, methyl ester (C17H34O2) n-hexadecanoic acid (C16H32O2) Hexadecanoic acid, ethyl ester (C18H36O2) octadecenoic acid, methyl ester (C17H34O2) Methyl stearate (C19H38O2) Ethyl oleate (C20H38O2) Octadecanoic acid, ethyl ester (C20H40O2) Total Table 5. Chemical composition of bio-oil obtained in toluene solvent. Retention Compounds name (Formula) Temperature ( o C) time (RT) % area % area % area Dodecanoic acid, methyl ester (C13H26O2) Dodecanoic acid (C12H24O2) Phenol, 2,6-dimethoxy-4-(2-prophenyl)- (C11H14O3) Tridecanoic acid, 12-methyl-, methyl ester (C15H30O2) Tetradecanoic acid (C14H28O2) Hexadecanoic acid, methyl ester (C17H34O2) n-hexadecanoic acid (C16H32O2) octadecenoic acid, methyl ester, (E)-(C19H36O2) Octadecanoic acid (C18H36O2) DEHP (impurities) Total

19 Table 6. Chemical composition of bio-oil obtained in n-hexane solvent. Retention Compounds name (Formula) Temperature ( o C) time (RT) % area % area % area Dodecanoic acid, methyl ester (C13H26O2) Dodecanoic acid (C12H24O2) Dodecanoic acid, ethyl ester (C14H28O2) Tetradecanoic acid, methyl ester (C15H30O2) Tetradecanoic acid (C14H28O2) Tetradecanoic acid, ethyl ester (C16H32O2) Pentadecanoic acid, methyl ester (C16H32O2) Pentadecanoic acid, ethyl ester (C17H34O2) Hexadecanoic acid, methyl ester (C17H34O2) n-hexadecanoic acid (C16H32O2) Octadecanoic acid, methyl ester (C19H38O2) Octadecanoic acid (C18H36O2) octadecenoic acid (C18H34O2) Octadecanoic acid, 10-oxo-,methyl ester (C19H36O3) Eicosanoic acid, methyl ester (C21H42O2) DEHP (impurities) Total The second higher component is octadecanoic acid, methyl ester. At temperature of 300 o C the percentage of octadecanoic acid, methyl ester is about %, at 350 o C the percentage of octadecanoic acid, methyl ester is about %, and at temperature of 400 o C the percentage of octadecanoic acid, methyl ester is about %. It s meant that the component of octadecanoic acid, methyl ester is just constant by increasing the temperature. From the tables above table 2 6 can be classified the compounds elimination by the solvent used. Each solvent has selectivity as esters, organic acids, and ketones/others from the degradation of biomass, as shown in Table 7. Each solvent has a major component in bio-oil product, methanol and ethanol solvents resulted mostly ketones/others as the main components, while toluene and hexane resulted organic acid as the main components, acetone gave the closed amount between ester and organic acid, as shown in Table 7. It s meant that the results of biomass degradation is strongly depend on the solvent type. The degradation of EFB in many types of organic solvents resulted hidro carbon from C 6 to C 21, it s meant that biomass degraded into smaller molecules and then reacted to each others of the reactive molecules into higher molecules. Before chemical reaction acts, the microcrystalline of cellulose reacts in suband supercritical solvents require an extra step and time to break down the cellulose crystallite. In subcritical water, the crystallite is hydrolyzed at the surface region without swelling or dissolving. Therefore, the overall conversion rate of microcrystalline cellulose is slow, and there is no cellulose crystal formed in the residue. In contrast, in near-critical and super-critical water, the crystallite can swell or dissolve around the surface region to form amorphous-like cellulose molecules. These molecules are inactive; therefore, they can be easily hydrolyzed to celluloses and cellooligosaccharides. Some of the hydrolysate can pass from the polymer phase to the water phase by cleavage of their hydrogen-bond networks (Yu, Lou and Wu, 2007). In the first step of reaction hydrolysis, dehydration and hydration were take places, celluose was converted into glucose and then into carboxylic acid in strong alkalines. In weak alkaline glucose converted into carboxylic acid and 5-hydroxymethyl furfurol (5-HMF). In medium alkaline both reaction pathways take places (Yin, Mehrotra and Tan, 2011). In acidic pathway 5-HMF further converted into formic acid and levulinic acid by hydration reaction, further dehydration reaction into 1,2,4 benzentriol (Yin and Tan, 2012). 14

20 Table 7. The selectivity of each solvent to the fraction of esters, acids and ketones/others Compound Organic Solvents selectivity Methanol Ethanol Acetone Toluene Hexane Temperatur e ( o C) Ester (%) Organic acid (%) Ketones/ Others (%) Total In the whole process, the substances of biomass are first hydrolyzed to small molecul compounds, then further reaction of repolimerization, decomposition and condensation of the intermediates from the different phase may be favored with the increment of reaction temperature and residence time (Gai et al., 2015). Carbohydrate is hydrolyzed to produce reduced sugar and non-reduced sugar. Glucose itself reversibly isomerizes into fructose, this is an important reaction since a number studies have confirmed that fructose is more reactive than glucose (Gai et al., 2015). Further fragmentation and dehydrations lead to the formation of a variety of low molecular weight compounds such as formic acid, acetic acid, lactic acid, acrylic acid, 1,2,4- benzenetriol. Formation of tar and darkening of the solvent phase was observed, indicating that more heavy products are formed (Toor, Rosendahl and Rudolf, 2011). Under liquefaction conditions, the cellulose degrades to low molecular weight aldehydes and ketones, those aldehydes and ketones then form aromatic compounds by condensation and dehydration. The reactive molecules like organic acids and aldehydes are converted by the reactions with alcohols into higher moleculs such as esters and acetals (Mahfud et al., 2007). A completed methods of esterification of bio-oil was reviewed by Hu et al. (2017). They reviewed many methods of esterification bio-oil in many environment mediums. Esterification of bio-oil under subcritical conditions is able to convert the carboxylic acids in bio-oil, but the phenolics may not be significantly converted due to the relatively low reaction temperature (Hu et al., 2012). Esterification in supercritical alcohols helps to convert the phenolics in bio-oil, Peng et al. (2009) found that the supercritical esterification was more effective than the sub-critical esterification. At temperature condition of 400 o C, for all solvents used there have a higher ester content compared to the other temperature operation (Table 7). Conclusions The decomposition of EFB in supercritical organic solvents liquefaction in the absence of catalysts has been performed successfully using batch reactor. Different organic solvents resulted the different of composition of soluble liquid/bio-oil. The bio-oil composition were composted from organic acids, ester and ketones/other. Each solvent type has a major component to each other. The methanol solvent resulted the major component was 2- pentanone,4-hydroxy-4-methyl-, followed hexadecanoic acid, methyl ester. The ethanol solvent resulted the major component was also 2-pentanone,4- hydroxy-4-methyl-, followed hexadecanoic acid, ethyl ester. The acetone solvent resulted the major component was n- hexadecanoic acid, and followed hexadecanoic acid, ethyl ester and 2- pentanone,4-hydroxy-4-methyl-, respecttively. Toluene solvent resulted the major component was n-hexadecanoic acid and followed by dodecanoic acid. The hexane solvent resulted the major component was n-hexadecanoic acid and followed by octadecanoic acid, methyl ester and dodecanoic acid, respectively. The increasing temperature from 300 to 400 o C was just slightly affecting the change of the major component of bio-oil in percentage. 15

21 Acknowledgments The research was supported by LIPI/Indonesian Institute of sciences. Internal project DIPA References Wang, M., Xu, C.C. and Leitch, M., Liquefaction of cornstalk in hotcompressed phenol water medium to phenolic feedstock for the synthesis of phenol formaldehyde resin. Bioresource technology, 100(7), pp Liu, H.M., Feng, B. and Sun, R.C., 2011a. Acid chlorite pretreatment and liquefaction of cornstalk in hotcompressed water for bio-oil production. Journal of agricultural and food chemistry, 59(19), pp Liu, H.M., Feng, B. and Sun, R.C., 2011b. Enhanced bio-oil yield from liquefaction of cornstalk in sub-and supercritical ethanol by acid chlorite pretreatment. Industrial & Engineering Chemistry Research, 50(19), pp El-barbary, M.H. and Shukry, N., Polyhydric alcohol liquefaction of some lignocellulosic agricultural residues. Industrial Crops and Products, 27(1), pp Chen, F. and Lu, Z., Liquefaction of wheat straw and preparation of rigid polyurethane foam from the liquefaction products. Journal of Applied Polymer Science, 111(1), pp Demirbaş, A., Mechanisms of liquefaction and pyrolysis reactions of biomass. Energy conversion and management, 41(6), pp Liu, Z. and Zhang, F.S., Effects of various solvents on the liquefaction of biomass to produce fuels and chemical feedstocks. Energy conversion and management, 49(12), pp Akhtar, J. and Amin, N.A.S., A review on process conditions for optimum bio-oil yield in hydrothermal liquefaction of biomass. Renewable and Sustainable Energy Reviews, 15(3), pp Smith, J.M. and Van Ness, H.C. (1959). Introduction to Chemical Engineering Thermodynamics, 2 nd, McGraw-Hill Book Company, Inc. Tokyo. Anon1. Dielectric Constant. Dielectric Constant.htm. Mazaheri, H., Lee, K.T., Bhatia, S. and Mohamed, A.R., Sub/supercritical liquefaction of oil palm fruit press fiber for the production of bio-oil: effect of solvents. Bioresource technology, 101(19), pp James, (2012). Polar Protic? Polar Aprotic? Nonpolar? All About Solvents. [online] Wikipedia. Avalibale at : File://I:/bio-oil3- solvents/all%20about%20solvents%20% Non-P [Accessed 23 Mei 2015]. Zhou, D., Zhang, S., Fu, H. and Chen, J., Liquefaction of macroalgae Enteromorpha prolifera in sub- /supercritical alcohols: direct production of ester compounds. Energy & Fuels, 26(4), pp Chen, Y., Wu, Y., Zhang, P., Hua, D., Yang, M., Li, C., Chen, Z. and Liu, J., Direct liquefaction of Dunaliella tertiolecta for bio-oil in sub/supercritical ethanol water. Bioresource technology, 124, pp Huang, H., Yuan, X., Zeng, G., Wang, J., Li, H., Zhou, C., Pei, X., You, Q. and Chen, L., Thermochemical liquefaction characteristics of microalgae in sub-and supercritical ethanol. Fuel Processing Technology, 92(1), pp Wettstein, S.G., Alonso, D.M., Gürbüz, E.I. and Dumesic, J.A., A roadmap for conversion of lignocellulosic biomass to chemicals and fuels. Current Opinion in Chemical Engineering, 1(3), pp Behrendt, F., Neubauer, Y., Oevermann, M., Wilmes, B. and Zobel, N., Direct liquefaction of biomass. Chemical engineering & technology, 31(5), pp Kruse, A. and Gawlik, A., Biomass conversion in water at C and MPa. Identification of key compounds for indicating different chemical reaction pathways. Industrial & Engineering Chemistry Research, 42(2), pp Sarwono, R., Triwahyuni, E., Aristiawan, Y., Kurniawan, H.H. and Anindyawati, T., Cellulose conversion of oil palm empty fruit bunch (EFB) into ethanol. J. Selulosa, 4(1), pp.1-6. Sarwono, R., Pusfitasari, E.D. and Ghozali, M., 2016, June. Hydrothermal liquefaction of palm oil empty fruit bunch (EFB) into biooil in different organic solvents. In AIP Conference Proceedings (Vol. 1737, No. 1, p ). AIP Publishing. 16

22 Yu, Y., Lou, X. and Wu, H., Some recent advances in hydrolysis of biomass in hotcompressed water and its comparisons with other hydrolysis methods. Energy & Fuels, 22(1), pp Yin, S., Mehrotra, A.K. and Tan, Z., Alkaline hydrothermal conversion of cellulose to bio-oil: Influence of alkalinity on reaction pathway change. Bioresource technology, 102(11), pp Yin, S. and Tan, Z., Hydrothermal liquefaction of cellulose to bio-oil under acidic, neutral and alkaline conditions. Applied Energy, 92, pp Gai, C., Zhang, Y., Chen, W.T., Zhang, P. and Dong, Y., An investigation of reaction pathways of hydrothermal liquefaction using Chlorella pyrenoidosa and Spirulina platensis. Energy Conversion and Management, 96, pp Toor, S.S., Rosendahl, L. and Rudolf, A., Hydrothermal liquefaction of biomass: a review of subcritical water technologies. Energy, 36(5), pp Mahfud, F.H., Melian-Cabrera, I., Manurung, R. and Heeres, H.J., Biomass to fuels: upgrading of flash pyrolysis oil by reactive distillation using a high boiling alcohol and acid catalysts. Process Safety and Environmental Protection, 85(5), pp Hu, X., Gunawan, R., Mourant, D., Hasan, M.M., Wu, L., Song, Y., Lievens, C. and Li, C.Z., Upgrading of bio-oil via acidcatalyzed reactions in alcohols A mini review. Fuel processing technology, 155, pp Hu, X., Gunawan, R., Mourant, D., Lievens, C., Li, X., Zhang, S., Chaiwat, W. and Li, C.Z., Acid-catalysed reactions between methanol and the bio-oil from the fast pyrolysis of mallee bark. Fuel, 97, pp Peng, J., Chen, P., Lou, H. and Zheng, X., Catalytic upgrading of bio-oil by HZSM-5 in sub-and super-critical ethanol. Bioresource technology, 100(13), pp

23 J.Lignocellulose Tech. 02 (2017), Journal of Lignocellulose Technology Journal homepage: Article Characterization of acetylated cellulose from oil palm frond fiber (Elaeis guineensis Jacq.) for composites application Wida B. Kusumaningrum 1*, Firda Aulya Syamani 1, Diaz Desiana 2, Lisman Suryanegara 1, Subyakto 1 1 Research Center for Biomaterial, Indonesian Institute of Sciences Jalan Raya Bogor Km 46, Cibinong, Jawa Barat, Indonesia Departement of Chemistry, Faculty of Mathematics and Natural Sciences, Jalan Raya Darmaga, Bogor, Jawa Barat, Indonesia *Corresponding author: wida.banar@biomaterial.lipi.go.id Received: 12 Agustus Received in revised form: 21 October Accepted: 10 December Published online: 29 December 2017 Abstract Oil palm frond (OPF) is found as fiber waste source from palm oil plantation abudantly. Cellulose derived from OPF could be utilized as a reinforcing agent for composite product. However, hydrophilicity, which is one of the natural properties of cellulose, cause a difficulty when cellulose is blended with polymer matrices, which are commonly hydrophobic. Chemical modification is needed in order to facilitate better interaction between cellulose and polymer matrices by mean of wettability enhancement. The objective of this research was to study the effect of reaction time on acetylated cellulose from oil palm frond pulp fiber. In this work, acetylation processes were conducted at 30 o C for 1, 3, and 5 h. The degree of substitution was quantified using back titration of saponification method, whereas universal attenuated total reflectance (UATR) and differential scanning calorimetry (DSC) were used to analyze the chemical composition and thermal behaviors of acetylated cellulose, respectively. Acetyl specific groups are detected for all acetylated cellulose by UATR analysis. DSC analysis showed by increasing of the degree of substitution, the melting point of acetylated cellulose increased. The results suggested that surface modification by acetylation onto cellulose fiber improved the thermal stability of cellulose for further application such as composite purposes. Keywords : acetylated cellulose, cellulose, oil palmfrond, pulp, thermal properties Introduction Oil palm industry and plantation in Indonesia are rapidly growing nowadays. According to the data, oil palm plantation has been reached 11,672,861 ha, in 2016 (Ditjenbun, 2016). Potential biomass of fibers are produced from oil palm industry and plantation, as by product, abundantly. One of promising fiber from oil palm plantation by product is oil palm frond (OPF), which is predicted up to 10.4 ton/ha/year. These fibers have not been utilized for functional product yet. 18

24 Utilization and processing of OPF fibers become more challenging particularly for composite production which could give contribution on material s value added. OPF fibers consist of cellulose three major components namely cellulose, hemicelluloses, and lignin. Cellulose was build by some anhydroglucoses chain which contain three hydroxyl groups in every single molecule. Therefore, cellulose become hydrophillic due to the hydroxyl groups are easy to bound with moisture. Blending cellulose with polymer matrices, which commonly hydrophobic, become more challenging because of weak interfacial bonding between cellulose and polymer. Some works have been done to modify the cellulose so that become morewell-dispersed and improve interaction into polymer matrices. Chemical modification is one of attempt to make cellulose become more hydrophobic. Acetylation, alkali treatment, silane treatment, and benzoil treatment have been done for cellulose modification. (Li, Lope and Panigrahi, 2007; Thielemans et al., 2008). Acetylation created better interfacial bonding and strong enhancement than of silane and alkali treatment (Abdul, 2014). Some parameters affected the acetylation process, such as temperature, reaction time, concentration of reactant, concentration of catalyst, and mixing speed. Previous study (Kusumaningrum, 2017) reported that reaction temperature influenced the degree of substitution and the morphology of acetylated cellulose. In addition, at the same catalyst concentration, reaction conducted at 30 o C resulted in a gel-like form of acetylated cellulose, whereas at 60 o C produced in a powder form of acetylated cellulose. Prasetiyo et al. (2014) had produced powder-acetylated-cellulose from empty fruit bunch pulp by condition of reaction temperature at 60 o C. Those powderacetylated-cellulose were undispersed onto poly lactic acid (PLA) due to the agglomeration was occurred and resulted low mechanical properties. Acetylation process could change sugarcane bagasse fiber morphology from fibrous into globular which further affect on mechanical properties reduction in PP composites. (Luz et al. 2008). PLA composites reinforced with a gel-like nanocellulose result better well dispersed and no agglomeration sheet which correspond in better mechanical properties (tensile strength and modulus). (Abdulkhani et al., 2014). Therefore, another form of acetylated cellulose (i.e gellike form) is preffered to be explored in further study to enhance the dispersion of acetylated cellulose in PLA. Some experiments have been done to produce acetylated cellulose at below room temperature (25 o C) using acetic anhydride as acetylating agent and sulfuric acid as catalyst. Yang et al. (2008) reported acetylation process which conducted at 0 o C showed the degree of substitution (DS) reached into 2.46 within 40 minutes of reac tion. While at 18.3 o C the acetylation process of kenaf fiber resulted in acetyl content arround 40.4 % within 2 h reaction time. (Widyaningsih and Radiman, 2007). Gaol et al. (2013) studied acetylated cellulose from empty fruit bunch pulp with degree of substitution of 1.68 at 25 o C for 2.5 h. All the acetylated cellulose produced was in gel-like form. In order to produce acetylated cellulose in a gel-like form, reaction temperature at 30 o C is preffered and consider for low energy consumption. The objective of this research was to study the effect of reaction time on characteristics of acetylated cellulose from bleached pulp of oil palm frond (OPF) which then can be utilized as reinforcing agent in PLA composites. The production of PLA composites can be conducted in wet process, so filler (acetyled cellulose) with similar form was expected can provide better dispersion. Materials and Methods Materials Oil Palm frond fiber, Fig. 1a, was used as raw material then through kraft pulping process achieved unbleached pulp with moisture content around 78% as shown in Fig. 1b. Unbleached pulp further bleached using Sodium Chlorite (NaClO 2) at pure grade analysis from MERCK Indonesia. Acetic acid (CH 3COOH) as activating agent, acetic anhydride (C 4H 6O 3) as acetylated agent, and sulfuric acid (H 2SO 4) as catalyst were used at pure analysis grade from MERCK Indonesia. While, ethanol 96% (C 2H 5OH) and acetone (C 3H 6O) that were used in solvent exchange process, were at technical grade. Sodium hydroxide (NaOH) and hydrochloric acid (HCl) that used for quantitative analysis were prepared at pure analysis grade from MERCK Indonesia. 19

25 a b min. Samples were kept at room temperature for 72 h. Titration was performed using hydrochloric acid 0.5 N and then back titration using sodium hydroxide 0.5 N was conducted after 24 h conditioning. Acetyl content was calculated by equation (1) and degree of acetylation by equation (2). Figure 1. (a) Oil palm frond, (b) Unbleached OPF pulp. Pulp bleaching process Bleaching process was conducted to eliminate lignin and hemicellulose content from unbleached pulp. Multi stages bleaching process were done as follows, 16 ml of sodium chlorite and 0.8 ml of acetic acid were added into erlenmeyer which contained of 10 grams of unbleached pulp and 600 ml aquadest. The mixture was heated at 80 o C. After an hour, the sodium chlorite and acetic acid at the same amount as before were added again into the erlenmeyer and reaction was continued at 80 o C for another an hour. The addition of sodium chlorite and acetic acid was repeated 4 times until brighten pulp was achieved. Acetylation process Prior to acetylation process, 1 g of bleached pulp was solvent exchanged with 50 ml ethanol 96% for 30 min then filtered, continued for second stage with 50 ml acetone for another 30 min. After solvent exchange, bleached pulp of OPF was activated with 20 ml of acetic acid for 1 h. Subsequently, acetylation process was conducted with 10 ml of acetic anhydride and 0.05 ml of sulfuric acid within determined reaction time (1,3, and 5 h) at 30 o C. Product obtained from the reaction was washed multiple times with distilled water, ethanol 96%, and acetone. For furthere characterization, sample was prepared by oven drying at 40 o C for 2 h. The samples were coded with PAC1, PAC 3, and PAC 5 whereas 1, 3, and 5 represent the reaction time. Degree of substitution Degree of substitution were analyzed by saponification method. Briefly, around 100 mg of acetylated cellulose was immersed in 10 ml of ethanol 75% and then heated at 60 o C for 30 min. An amount of 12 ml sodium hydroxide 0.5 N was added then further heated at 60 o C for Acetyl content (%) = Degree of substitusion = [(D C) + (A B)]N x 4,305 W 3,86 x acetyl content (%) 102,4 acetyl content (%) (1) where A is sodium hydroxide volume of samples, B is blank sodium hydroxide volume, C is hydrochloric acid volume of samples, D is blank hydrochloric acid volume, N is determined in 0.5, and W is sample s weight. Chemical composition analysis Perkin elmer Universal attenuated total reflectance (UATR) Two was used to analyze specific functional groups of materials. Around 5 mg of samples was placed on diamond reflectors, then scanned in proper position. The spectrum of wavenumber was determined in the range 400 4,000 cm -1 and scanning repetition in 5 times. Thermal properties Differential scanning calorymetry (DSC) 4000 perkin elmer equiped with intercooler was used to analyze thermal characterization of acetylated cellulose. Scanning method was performed as follows, about 5 mg of samples was placed in alumunium pan then heated from 30 to 300 o C againts an empty pas as a reference with heating rate 10 o C/min. Results and Discussion Degree of Substitution Degree of substitution (DS) is correspond to acetylating agent ability to substitute hydroxyl groups with acetyl groups on cellulose. Higher DS value indicate more hydroxyl groups that substitute by acetyl groups. DS and acetyl content for acetylated cellulose from OPF pulp at various reaction time are represented on Table 1. The results show that acetyl content and DS increased as the reaction time increased. However, acetyl content and DS decreased at 5 h reaction time. It could be caused by cellulose chain degradation into glucose monomer. The (2)

26 longer the reaction time, the faster sulfuric acid will hydrolyze the cellulose. Savitri, Wijaya and Kaligang (2004) and Zhang et al. (2013) stated that with longer reaction time, cellulose will degrade into glucose and cellulose acetate into glucose acid. Gaol et al. (2013) has produced cellulose acetate from empty fruit bunch fiber at reaction temperature of 25 o C with acetic acid activation and resulted DS 1.68 by 2.5 h of reaction time. By the same process, with acetic acid as acetylating agent, resulted acetylated cellulose achieved DS 2.31 in 3 h of reaction time, as shown in Table 1, which indicate that temperature accelerate the reaction. Popescu et al. (2012) has produced acetylated cellulose from wood pulp at reaction temperature of 30 o C without acetylating agent and result DS 0.82 within 24 h of reaction time. This result indicate that acetylating agent is added to obtain acetylated cellulose in shorten time. In case of acetylation process, cellulose, hemicellulose and lignin of fibers would be affected by the substitution. According to Yang et al. (2008), hemicellulose and lignin which are as amorphous part of fiber, are more reactive than cellulose which is crystalline part of fiber. This phenomenon was because bonded hydroxyl groups on cellulose are more difficult to be accessed than free hydroxyl groups on amorphous part. Some studies report that hemicellulose and lignin provide more rapid reaction rate compare to cellulose and become more reactive with the increasing of it s composition in fiber (Ramsden and Blake, 1997; Popescu et al., 2012). Therefore, pretreatment process related delignification should be conducted in order to eliminate amorphous part. One of drawback on acetylation process in OPF pulp is the difficulty of acetylating agent to penetrate into cellulose chain, due to pulp morphology commonly easy to agglomerate. To overcome the problem, activating agent was needed. In this work, acetic acid could be act as dispersion agent beside as activating agent. After cellulose dispersion, proton from sulfuric acid attack the carbonyl groups of acetic anhydride and produced alcoholic groups. Actually, acetylation was a nucleophilic crackdown between hydroxyl groups of cellulose with acyl groups of acetic anhydride. (Das, Ali and Hazarika, 2014). Table 1. Acetyl content and degree of acetylation of acetylated cellulose from OPF Sample Acetyl content (%) Degree of substitution PAC PAC PAC Chemical Composition Analysis UATR could reflect some specific groups for particular chemical bond. Fig. 2 represent for UATR analysis of bleached OPF and acetylated cellulose from OPF at various reaction times. Acetylated cellulose from OPF was successfully produced on operation condition at 30 o C of temperature reaction. In this case, hydroxyl groups have been substituted with acetyl groups as shown on Fig. 2. Intensity of hydroxyl groups, at 3,400 cm -1, decreased by acetylation process for all reaction time, those suggested that some hydroxyl groups was converted into acetyl groups. Specific functional groups of acetylated cellulose were detected for all reaction time variation, which were indicated by peaks at 1,737 1,735 cm -1 for C=O stretching, 1,366 1,368 cm -1 for CH 3 stretching, and 1,213 1,220 cm -1 for C-C-O stretching. (Popescu et al., 2012; Ernest, Pawlak ad Lee, 2014; Ashori et al., 2014). Interestingly, the absence of functional groups at 1,840 cm -1 for all acetylated cellulose indicated that the product was free from unreacted acetic anhydride. And also, the absence of functional groups at 1,700 1,760 cm -1 indicated that all acetylated cellulose were free from carbocylic groups, suggested the elimination of acetic acid by product. Furthermore, functional groups at 1,600 cm -1 also undetectable for all acetylated cellulose which proved that all products were free from bonded water. On the other hand, the peak at 1,600 cm -1 was detected on untreated OPF pulp which showed that untreated OPF still contained bonded water. This result emphasized that all acetylated cellulose are more hydrophobic than untreated OPF pulp. 21

27 Figure 2. UATR spectra of bleached OPF and acetylated OPF at various reaction time Thermal Properties Thermal properties of material could be analyzed using DSC. Chemical treatment on fibers could changed the fiber s structure and influenced the fiber s properties such as thermal characteristic. Information of thermal characterization is needed in order to determine proper manufacturing, storing, and processing condition. Fig. 3 provides information about melting temperature for acetylated cellulose. DSC thermogram informs that melting point of acetylated cellulose reached o C, o C, and o C for PAC 1, PAC 3, and PAC 5 respectively. This result suggest that higher DS could increase melting point of acetylated cellulose. PAC 3 which has DS 2.31 result the highest melting point at o C. The high melting point of acetylated cellulose expand the range of processing condition. And therefore, acetylated cellulose are potential to be applied with various thermoplastic polymer (i.e polypropylene, polyethylene, polylactic acid) for composite production. Some studies have been done for similar temperature and obtain acetylated cellulose on gel form. Santoso (2007) has produced acetylated cellulose with melting point reach o C and acetyl content 39.31%. Whereas Gaol et al. (2013) produced acetylated cellulose with melting point range at o C and acetyl content about 22 31%. This result confirmed that melting point of acetylated cellulose increase as the DS increase. DS of acetylated cellulose become consideration on process pathway selection for compounding with matrices polymer. PAC 3 which has DS up to 2.31 and acetyl content 38.39% could be disolved in acetone. (Kirk et al, 1993). One of problem on composite 22 Figure 3. DSC analysis of acetylated cellulose from OPF at various reaction time production is the difficulty of fiber dispersion into polymer matrices. Amorphous PLA which is dissolved in acetone might be well mixed with PAC 3. Furthermore, PAC 3 melting point which was o C, allow to be molded with PLA which is melted at 180 o C without cause fiber degradation. Conclusion A gel-like acetylated cellulose from bleached OPF pulp has been successfully produced with operation condition at 30 o C and 5% (w/v) catalyst concentration. Reaction time affected the acetyl content, DS, and melting point of acetylated cellulose. PAC 3, acetylated cellulose which produced in 3 h of reaction time, show the highest acetyl content, DS, and melting point (Tm) compare to PAC 1 and PAC 5. Specific functional groups of acetylated cellulose also detected in all samples. Acetyl content, DS, and thermal characteristic reveal that PAC 3 could be dissolved in acetone and further might be well mixed with amorphous PLA for composite production. References Abdul, H.P.S. (2014). Production and Modification of Nanofibrillated Cellulose using Various Mechanical Process. Carbohydrate Polymer, 99, Abdulkani, A., Jaber, H., Alireza, A., Saeed, D., and Zahra, T. (2014). Preparation and characterization of modified cellulose nanofibers reinforced polylactic acid nanocomposite. Polymer Testing, 35, Ashori, A., Babaee, M., Jonoobi, M., and Hamzeh, Y. (2014). Solvent Free Acetylation of Cellulose Nanofibers for Improving Compatibility and Dispersion. Carbohydrate Polymer, 102, Das, A.M., Ali, A.A., and Hazarika, M.P. (2014). Synthesis and Characterization of Cellulose Acetate from Rice Husk: Eco-friendly

28 condition. Carbohydrate Polymer, 112, Direktorat Jenderal Perkebunan (Ditjenbun). (2016). Statistik Perkebunan Indonesia Kelapa Sawit , Sekretariat Direktorat Jenderal Perkebunan Kementerian Pertanian, pp Ernest-Saunders, R., Pawlak, J.J., and Lee, J.M. (2014). Properties of Surface Acetylated Microfibrillated Cellulose Relative to Intra and Inter Fibril Bonding. Cellulose, 21, Gaol, M., Lumbon, Sitorus, R., Yanthi, S., Surya, I., dan Manurung, R. (2013). Pembuatan Selulosa Asetat dari Alfa Selulosa Tandan Kosong Kelapa Sawit. Jurnal Teknik Kimia, 2(3), Krik, R.E., and Othmer, D.F. (1993). Encyclopedia of Polymer Science and Technology, New York: Interscience Publisher. Kusumaningrum, W.B. (2017). Biokomposit Polipropilena Berpenguat Selulosa Terasetilasi Dari Pulp Bambu Betung (Dendrocalamus Asper). Thesis, Yogyakarta: Universitas Gadjah Mada, pp Li, Xue, Lope. G.T., and Panigrahi. S. (2007). Chemical Treatments of Natural Fiber for Use in Natural Fiber-Reinforced Composites ( A Review ). Journal Polymer Environment, 15, Luz, S.M., Tio, D.J., Rocha,G.J.M., Goncalves, A.R., and Del Arvo, A.P. (2008). Cellulose and Cellulignin from Sugarcane Bagasse Reinforced Polypropylene Composites : Effect of acetylation on mechanical and thermal properties. Composites Part A, 39, Popescu, C., Larsson, P.T., Olaru, N., and Vasile, C. (2012). Spectroscopy study of acetylated kraft pulp fibers. Carbohydrate Polymer, 88, Prasetiyo, K.W., Kusumaningrum, W.B., dan Suryanegara, L. (2015). Karakteristik Komposit Poli(Asam Laktat) Dengan Pulp Tandan Kosong Kelapa Sawit Yang Termodifikasi. Proceeding of Seminar Nasional Mapeki XVII, Medan, 11 November 2014, Ramsden, M.J., and Blake, F.S.R. (1997). A Kinetic Study of The Acetylation of Cellulose, Hemicellulose, and Lignin Components in Wood. Wood Science and Technology, 31, Santoso, S.D. (2007). Sintesis Selulosa Diasetat dari Serat Daun Nanas (Ananas comusus). Thesis, Surabaya: Unversitas Airlangga. pp. 3 Savitri, E., Wijaya, A., dan Kaligang, P. (2004). Penentuan Kondisi Optimum Sintesis Selulosa Asetat dari Serat Garut (Marantha arundinaceae L) dengan metode response surface. Prosiding Seminar Nasional Rekayasa Kimia dan Proses, pp. G18-1 G18-6. Thielemans. B.L.W, Dufresne.A, Chaussy.D, and Belgacem, M.N. (2008). Surface functionalization of cellulose fibers and their incorporation on renewable polymer matrices. Composites Science and Technology, 68, Widyaningsih, S., dan Radiman, C.L. (2007). Pembuatan Selulosa Asetat dari Pulp Kenaf (Hibiscus cannabius). Molekul, 2(1), Yang, Z., Xu, S., Ma, X., and Wang, S. (2008). Characterization and Acetylation Behaviour of Bamboo Pulp. Wood Science Technology, 42, Zhang, G., Huang, K., Jiang, X., Huang, D., and Yang, Y. (2013). Acetylation of Rice Straw for Thermoplastic Applications. Carbohydrate Polymer, 96,

29 J.Lignocellulose Tech. 02 (2017), Journal of Lignocellulose Technology Journal homepage: Article Bioactivity of liquid smoke of rice husk against Spodoptera exigua Arief Heru Prianto 1*, Fifi Alami Fahlawati 2, Dede Sukandar 2 1 Research Center for Biomaterials, Indonesian Institute of Sciences, Cibinong Science Center, Cibinong-Bogor 16911, Indonesia 2 Syarif Hidayatullah State Islamic University Ciputat, Jakarta *Corresponding author:ariefprianto@gmail.com Received: 22 September Received in revised form: 27 October Accepted: 30 November Published online: 29 December 2017 Abstract The characteristics and bioactivity of liquid smoke produced from rice husk as antifeedant activity against Spodoptera exigua larvae were investigated. The carbonation process of rice husk was conducted into low heating rate ( o C). The organic components in the liquid smoke were analyzed to determine the major composition. Bioassay of S. exigua was carried out by using crude liquid smoke and its fractions to find out the feeding inhibitory. The feeding inhibitory of S. exigua on liquid smoke fraction increased significantly with increasing temperature of the carbonation process. It was clearly observed that liquid smoke fraction at o C was the most effective as antifeedant against S. exigua. In addition, two major toxic compounds, i.e., phenolic and acid were much concentrated in that fraction. We suggest that those compounds might responsible to feeding inhibitory activities of S. exigua larvae. Keywords : liquid smoke, rice husk, Spodoptera exigua, antifeedant activity Introduction Carbonation process is decomposition of lignocellulosic biomass components, i.e., cellulose, hemicelluloses and lignin to generate liquid smoke. Such process can be divided into tree modes based on heating rate: fast, intermediate, and slow (Wu et al., 2015). Zhai et al. (2015) also reported that heating temperature influenced the proportion of yielded compound in pyrolysis. Some earlier studies reported that liquid smoke has an antifeedant activity (Wu et al., 2015; Yatagai et al., 2002). Gani et al. (2012) identified γ-butyrolactone as antifeedant compound from the liquid smoke of organic waste. The compound caused detrimental effect against Spodoptera litura larvae. Research on antifeedant activity of plant extracts have been immensely conducted. Chinnamani and Jeyasankar (2018) reported that Pseudocalymma alliaceum, Solanum pseudocapsicum and Barleria buxifolia 24

30 showed significant antifeedant activity against the fourth instar larvae of S. litura and Helicoverpa armigera. Some antifeedant compounds have been isolated from Gnaphalium affine (Morimoto et al., 2003). Arivoli and Tennyson (2012) also reported the antifeedant activity in hexane washed leaf extracts of Zanthoxylum limonella against S. litura (77.52%). On the other hand, rice husk is abundantly, and typically of lignocellulosic biomass, rice husk can be used as a source of liquid smoke. Besides that rice husk is an organic waste that has not been fully utilized. Tajali (2015) reported that chemical contents of rice husk are carbon (charcoal) 1.33%, hydrogen 1.54%, oxygen 33.64% and silica 16.98%. Based on the literature survey, little is known regarding the bioactivity of liquid smoke produced from rice husk against pest insects. Therefore, the present study was conducted to assess the bioactivity of liquid smoke produced from rice husk as antifeedant for S. exigua larvae. Material and Methods Liquid smoke production In this research, rice husk was used as raw material to produce liquid smoke. The carbonation process was carried out using a pyrolysis reactor. Rice husk sample was weighed and then put into pyrolysis reactor. The pyrolysis reactor was closed tightly. The pyrolysis process has lasted for 4 hours at temperatures between C. Liquid smoke was accommodated in the three temperature ranges, i.e., C, C and C. Total phenolic content One ml of liquid smoke was diluted in 500 ml water. One ml of dilution concentration and 5 ml of 15% sodium carbonate were applied to a test tube, and allowed to stand at room temperature for 10 minutes. Folin-Ciocalteau reagent (0.5 ml) was then added and mixed with vortex - shaker. The solution was incubated at room temperature for 30 minutes. UV - VIS Spectrophotometer was used to measure absorbance of samples at 750 wavelengths. Phenolic content was calculated based on a standard curve of pure phenol solution. Total acid content One ml of liquid smoke was put into 100 ml of distilled water, then homogenized. Phenoptaline indicator (0.3 ml) was added into the solutions and titrated with 0.1 N NaOH. Titration was stopped when color changes in solution from clear yellow to yellowish brown color. The total acid content was calculated by the following formula. Total acid (%) = (V x N x MW) x 100 (SW x 1000) Where: V : volume (ml) N : normality of NaOH (N) MW : molecular weight of acetic acid (g/mol) SW : weight of sample (g) Bioassays against S.exigua larvae Bioassay used in this experiment is a modified method developed by Arivoli and Tennyson (2012). Onion leaves (15 x 20 mm) were used for bioassay test. The leaves were dipped into the solution for 20 seconds and air dried at room temperature. Two pieces of onion leaves (Allium cepa), i.e., treated and untreated were put into the Petri dish. One of third instar larvae of S.exigua was then placed in each dish after being starved for 2 hours. Observations were conducted after 24 hours by measuring the consumed leaf area with millimeter block. The percentage of antifeedant activity was calculated by the feeding inhibitory formula: FI (%) = (leaf area consumed (control - treatment)) (leaf area consumed (control + treatment)) FI = Feeding inhibitory activities 25

31 Table 1. The yield of rice husk liquid smoke Sample Weight (gram) Temp ( C ) Volume (ml) Yield (%) ph Colour Brown Dark Brown Results and Discussion In this study, we first carbonated of rice husk in low moisture content (8.13%) to maximize the liquid smoke`s yield. We applied around 1064 g of rice husk as maximum capacity of a pirolisator, and allowed the pyrolysis process for 4-5 hours. As mentioned above, the carbonation was divided into three fractions based on the differences of temperature, i.e., at C, C and C. Our data demonstrated that the third fraction produced different characteristic of liquid smoke with more intense color of the liquid smoke or darkening (Table 1). We speculate that this phenomenon may be induced by phenol and tar content, in which phenol and tar content in the third fraction likely higher than that in the other fractions. Supporting this, an earlier study suggested that phenol and tar are the result of lignin decomposition at high temperature (Loo A.Y, 2008). As shown in Table 1, the largest liquid smoke was produced at C (29.9%) while the smallest liquid smoke was yielded at C (2.09%). This condition was generated by evaporation of water and degradation of cellulose and hemicellulose, as major compounds of rice husk, at C, Rice husk consists of three major components, i.e., cellulose, hemicelluloses, and lignin. Since the degradation of hemicellulose, cellulose and lignin occurred at C, C and C, respectively (Loo, 2008), the highest yield of liquid smoke was possibly produced at C. In carbonation process, the cellulose produced acetic acid, hemicellulose produced acetic acid, furan and furfural while lignin generated phenol, phenol derivatives and tar formation (Darmadji, 1996). Figure1. Total phenolic content of liquid smoke Thus, it has been well understood that the determination of liquid smoke`s yield is the one of the most important parameters to determine the output of the process (Prianto, 2015). The present study noted that total yield of carbonation process was 34.65%. Gani et al. (2007) revealed that the amount yield of liquid smoke produced in the carbonation process depends on the process conditions and the type of used raw materials. In addition, percentage of yields obtained from the carbonation are also highly depend on carbonation temperature and condensation systems (Wijaya et al., 2008), therefore the high of carbonation temperatures may resulted in reducing the liquid smoke. Besides that, our liquid smoke`s yield is consistent with the previous study by Halim et al. (2004). In this study, we also observed the degree of acidity (ph) of liquid smoke. The result showed that ph of liquid smoke was 2.77 to 3.11 (Table 1). Wijaya et al. (2008) reported that low ph value indicate the high quality of liquid smoke especially in its use as a preservative. 26

32 Figure 2. Acid content of liquid smoke phenolic compounds and organic acids, and the synergistic effect of phenolic compounds with organic acids has a higher effect in inhibiting feeding level. Supporting this, some earlier studies suggested that phenolic and acid compounds have detrimental effect to pest insect (Yatagai, 2002). Liquid smoke contains some compounds that are suspected to be toxic, repellent and antifeedant activity such as phenols and organic acids, so that liquid smoke has an opportunity as a biopesticide to control pests (Ma et al., 2011; Prianto, 2015; Yatagai et al., 2002). Gani (2007) also reported that methanol and water fractions of liquid smoke have potential as antifeedant activity more than 50%. Conclusions Figure 3. Feeding inhibitory activities Next, we analyzed the chemical compounds in the liquid smoke produced from rice husk. The present study detected two major compounds in the liquid smoke, i.e., phenolic and acid compounds (Figs. 1 and 2). Our data noted that 1.6% phenolic, and 11.03% acid compounds were consisted in the liquid smoke at C (Fig. 1 and Fig. 2). We also detected that largest acid compound in the liquid smoke is acetic acid. Yatagai et al. (2002) suggested that acid acetic acid is the largest component in the liquid smoke. Another study by Mustikawati et al. (2016) also reported that cconcentration of acetic acid and phenol in liquid smoke from rice husk were 72.22%, and 12.39%. Lastly, we tested the liquid smoke and its fractions against S.exigua larvae. Our data presented here, showed that the highest of feeding inhibitory activities occurred at C with time observation was 24 hours (91.71%) (Fig. 3). As discused above that phenolic and acid compounds are consisted in liquid smoke with carbonation process at C. We suggest that feeding inhibitory activities of S.exigua were caused by the presence of Overall, the feeding of S. exigua on liquid smoke fraction increased significantly with increasing temperature of carbonation. We observed that liquid smoke fraction at o C was the most effective as antifeedant against S. exiqua with 94.71% of the feeding inhibitory. In addition, our chemical components analysis clearly confirmed that two major compounds i.e., phenolic and acid compounds are consisted in the liquid smoke. We suggest that those compounds have synergetic effect in the feeding inhibitory of S. exigua. This finding contributes to improve the value-added of rice husk as a source of liquid smoke as agent for controlling pest insects. References Arivoli S and Tennyson S. (2012). Antifeedant Activity of Plant Extracts Against Spodoptera litura (Fab.) (Lepidoptera: Noctuidae). American-Eurasian J. Agric. & Environ. Sci., 12 (6): Chinnamani, T and Jeyasankar, A. (2018). Screening of Plant Extracts for Antifeedant Activity Against Spodoptera litura and Helicoverpa armigera (Lepidoptera: Noctuidae). Insight Bacteriology, 7: 1-6. Darmadji, P. (1996). Antibakteri asap cair yang diproduksi dari bermacam-macam limbah pertanian.agritech. 16 (4), Gani, H. A, Mas ud, Z. A., Lay, B. W., Sutajhjo, S. H. dan Pari. G. 27

33 (2007).Karakterisasi asap cair hasil pirolisis sampah organik padat. Jurnal Teknologi Industri Pertanian, 16(3), Gani, H A, Zainal Alim Masud dan Gustan Pari. (2012). Identifikasi Senyawa Bioaktif antifeedant dari asap cair hasil pirolisis sampah organik perkotaan. Jurnal bumi lestari 12, 1-8 Halim. M., P. Darmadji dan R. Indrati. (2004). Fraksinasi dan identifikasi senyawa volatil asap cair cangkang sawit. Agritech. 16 (3), Ismunadji, M dan S.O. Manurung. (1988). Badan Penelitian dan Pengembangan Pertanian. Bogor. pp Loo Ai Yin Isolation and characterization of. Antioxidant compounds from pyroligneous. Acid of Rhizophora apiculata. Thesis submitted in fulfilment of the requirements for the degree of doctor of philosophy. Universiti Sains Malaysia. June 2008 Ma X, Q Wei, S Zhang, L Shi, Ana Z, and Zhao. (2011). Isolation and bioactivities of organik Acid and phenols from walnut shell pyroligneous Acid. Journal of analitical and applied pyrolysis. 91, Morimoto, M, Kumiko T,Sachiko N, Takayoshi O, Ayako N and Koichiro K. (2003). Insect Antifeedant Activity of Flavones and Chromones against Spodoptera litura. J. Agric. Food Chem., 51 (2), Mustikawati, D. R, Mulyanti N, and Arief, R W Study Effectiveness of Liquid Smoke as a Natural Insecticide for Main Pest Control of Soybean Crops. International Journal of Sciences: Basic and Applied Research. Vol. 30, No 1, pp Prianto, A. H., Annisa K, dan Atiek. (2015). Aktivitas anti bakteri asap cair cangkang sawit (Elaensis guineensis) terhadap bakteri Staphylococcus aureus dan Pseudomonas auruginosa. Prosiding Seminar Unggulan Bidang Pangan Nasional. Bogor, 25 September 2014 Hal ISBN Tajalli, A. (2015). Panduan penilaian potensi biomassa sebagai sumber energi alternatif di Indonesia. Penabulu alliance Wijaya M, E Noor, T Tedja I, dan G Pari. (2008). Karakterisasi Komponen Kimia Asap Cair dan Pemanfaatannya sebagai Biopestisida. Bionature Vol.9 (1): Wu Qiaomei, Shouzu Z, Baoxin H, Hongjun Z, Wenxiang D, Dahai L, and Wenjiao T. (2015). Study on the preparation of wood vinegar from biomass residues by carbonation process. Bioresourches Technology 179, Yatagai, M., M. Nishimoto, K.Hori, T.Ohira. and A.Shibata. (2002). Termiticidal activity of liquid smoke,its component and their homologues.j. Wood Science. 48, Zhai M, Xinyu W, Yu Z, Peng D, and Guoli Q. (2015). Characteristics of Ice Hulk tar pyrolysis Bay External flu gas. International Journal of Hydrogen Energy,

34 J.Lignocellulose Tech. 02 (2017), Journal of Lignocellulose Technology Journal homepage: Article Characteristics of composite film from polyvinyl alcohol reinforced by bleached pulp of oil palm frond and agar powder of Gracillaria sp. Firda Aulya Syamani Research Center for Biomaterial Indonesian Institute of Sciences (LIPI) Jl. Raya Bogor Km. 46, Cibinong, Jawa Barat, Indonesia * Corresponding author: firda.syamani@biomaterial.lipi.go.id Received:10 November Received in revised form: 1 December Accepted: 25 December Published online: 29 December 2017 Abstract Soda pulp of oil palm frond (OPF) was bleached with hydrogen peroxide (50%v/v). Agar powder of seaweed Gracillaria sp. was used as received. Film composites were produced by blending OPF bleached pulp or Gracillaria sp. Agar into polyvinyl alcohol (PVA) solution. The OPF bleached pulp or Agar powder performed as reinforcing agent in polyvinil alcohol matrix. The amount of OPF bleached pulp or Agar was 5%, 10% or 15% from total weight of composites. Furthermore, PVA based composite films were also made from combination of OPF bleached pulp and Agar powder with varied ratio of OPF bleached pulp and Agar powder (5%/5%, 10%/5%, 5%/10%). The objective of this research was to identify the effect of OPF bleached pulp or Agar powder addition in PVA matrix on mechanical and thermal characteristics of composite films. Keywords : Agar powder, composite film, mechanical and thermalcharacteristics, oil palm frond pulp, polyvinyl alcohol Introduction Polivinyl alcohol (PVA) is a non toxic polymer (Tang et al., 2009). PVA has an excellent film-forming ability, good transparency and flexibility. PVA also shows a good thermal stability and chemical resistance. Based on those properties, PVA is widely used in several applications such as paper coating, packing, biomedical devices, and membrane preparation (Ollier, Perez and Alvarez, 2013). Characteristics of PVA were influenced by its moleculer weight and degree of hydrolysis, as consequences of polyvinyl acetate hydrolysis for PVA production (Pal, Banthia and Majumdar, 2006). PVA has strong hydrophilicity and large swelling capacity due to hydroxyl (OH) groups in its molecules (Yin, Fan and Zhou, 2015). The utilization of PVA in paper coating had been done. PVA has also used as textile thread or fabric coating (Palanikkumaran, Agrawal and Jassal, 2008) and tablets coating (Kadajji and Betageri, 2011). PVA and starch sheet 29

35 composites, prepared through casting technique has been utilized as mulch for agriculture (Chen et al., 1997) and also as water soluble laundry bag (Wood, 1987). PVA and cellulose sheet were produced from N,N-dimetylacetamide-lithitum chloride show a good compatibility because PVA can form intermoleculer hydrogen bond with cellulose (Nishio et al., 1989). However, PVA has some drawbacks, such as its low mechanical dan integrity. Many efforts have been conducted to overcome those problems such as crosslinking (Ding et al., 2002), mixing (Huang et al., 2009), or inserting filler for example carbon nanotubes (Jeong et al., 2007), hydroxyapatite nanoparticle (Kim et al., 2008), gold (Bai et al., 2007), silver (Hong, 2007), clay (Adanur and Ascioglu, 2007), silica (Shao et al., 2003), cellulose nanofibril (Medeiros et al., 2008), and chitin whiskers (Junkasem, Rujiravanit and Supaphol, 2006). Among fillers that has been used in PVA composites, cellulose fibers are the most potential sources due to its biodegradable properties, high mechanical properties, abundantly and availability. Cellulose fibers can be extracted from plants or other lignocellulosic materials such as oil palm frond (OPF). Oil palm is still the most important plantation resources as the source of Indonesian non oil and gas commodity. In 2016, oil palm plantation area was Ha. Riau province has the largest oil palm plantation area in Indonesia, which was Ha (Directorate General of Plantation, 2016). OPF is by product from oil palm plantation during oil palm fruit harvesting. In a year, every hectare of oil palm plantation produces 6 tons OPF, averagely (Supardjo, 2014). By that condition, the potential of OPF in Indonesia could reach up to 71.4 million tons in Some OPFs were utilized as plantation compost and cattle feed. Another utilization of OPF was as reinforcing agent in polymer base composites. Kusumaningrum et al. (2011) reported the mechanical properties of PVA composites reinforced by bleached and unbleaced empty fruit bunch fiber (OPEFB). While in 2014, Kusumaningrum et al. reported the effect of ultrasonification process on unbleached OPEFB pulp as 30 reinforcing agent in PVA composites. So far, there has no report studied about PVA-OPF composites yet. Nevertheless, there is still a large amount of un-utilized OPF and it can cause problems to the environment. Meanwhile, as an archipelago country, Indonesia potency of seaweed is also abundant. From seaweed cell wall, we can extract Agar, which is a polysaccaride of agarose and agaropectin (Lyons et al., 2009). Agar can be melted in hot water if heated and solidified if left in room temperature. The changing of Agar s form can be repeated without effect on Agar gel s mechanical properties. The Agar s ability is influenced by its molecular weight and chemical characteristics (Mouradi- Givermaud et al., 1992). Agar has been used as filler in many kinds of polymer, such as PVA (Lyons et al., 2009, Medera- Santana et al. 2011), polypropylene (Hassan, Mueller and Wagners, 2008). Besides that, Agar can be used along with other fibers to produce hybrid composites. Hasan et al. (2010) had developed composites from rice straw fibers-seaweedpolypropylene (PP) while Prachayawarakorn et al. (2012) had produced composites from cotton fibers-agar-rice starch. Such utilization of OPF fibers and Agar as informed previously, give us guideline that those by products can be utilized to produce higher added value products. The objective of this study was to investigate the effect of OPF pulp or Agar powder addition into PVA matrix on the mechanical and thermal characteristics of composite film. Materials and Methods Oil palm fronds (OPF) were obtained from oil palm plantation in Banten Province, Indonesia. Agar powder was a commercial grade and used without further purification. Chemical compounds for pulping and bleaching were technical sodium hydroxide (NaOH) and hydrogen peroxide (H 2O 2) solution (50% v/v), respectively. Pulping process OPF fibers were cut into 3-5 cm, after that put in a digester. NaOH solution (45%) was added into digester with ratio of fiber:naoh solution of 1:8. OPF fibers were cooked at 176 C for 2 h 46 min. This pulping condition was based on an optimum cooking condition from previous

36 Tensile Strength (MPa) study (Syamani, Subyakto and Suryani, 2015). After cooking, pulp was washed and neutralized with tap water. Bleaching process OPF soda pulp was bleached using H 2O 2 solution. OPF soda pulp (100 g) was put into glass container, then aquadest (2500 ml) and H 2O 2 solution (50 %, 25 ml) was added. Bleaching process was conducted in waterbath on temperature of 75 C for 1 h. After an hour, as much as 25 ml H 2O 2 (50%) was added again and bleaching process was continued for 1 h. Bleaching process was conducted in 4 cycles (total 100 ml H 2O 2 solution was added). After bleaching, pulp was washed and neutralized with tap water. Composite production PVA was diluted in aquadest at 80 C using magnetic stirrer at 200 rpm for 30 min. In the meantime, OPF bleached pulp was fibrillated by stirring in beaker filled with water at 500 rpm for 30 min. The fibrillated OPF bleached pulp, then added into PVA solution with amount as presented in Table 1. The mixing of OPF bleached pulp and PVA solution was conducted at 500 rpm for 30 min. After well mixed, the solution of PVA-OPF bleached pulp was poured into 10 x 15 cm molding, then air-dried at room temperature over night. The drying process was continued in oven at 60 C for 3 h. Table 1.Film Composite Composition Code Composites PVA (g) Pulp (g) Agar (g) P1 Bleached Pulp 5% P2 Bleached Pulp 10% P3 Bleached Pulp 15% A1 Agar 5% 19-1 A2 Agar 10% 18-2 A3 Agar 15% 17-3 A1P1 Agar 5%, Bleached Pulp 5% A1P2 Agar 5%, Bleached Pulp 10% A2P1 Agar 10%, Bleached Pulp 5% Analysis of Composite Morphology Composite surface morphology was analyzed using DinoLite microscope with 200x magnification. Analysis of Composite Mechanical Properties Film composites were cut into 10 x 2 cm sheets. Analysis of composite 31 mechanical properties was based on ASTM D (Standard Test Method for Tensile Properties of Thin Plastic Sheeting). The load speed was 500 mm.min -1 and length of initial grip separation was 50 mm. Analysis of Composite Thermal Properties Thermal properties of film composites (5.0 mg) were analyzed using DSC4000 (Perkin Elmer) at temperature range of C. The Heating speed was 25 C/min. The transition glass temperature, melting temperature and melting enthalpy were determined based on heating scan graphic. The composite crystalinity was calculated from the following equation : % Crystalinity = Hm / WPVA. Hm * 100% (1) where Hm is the experimental heat of fusion obtained from the area of the melting peak, W PVA is the PVA weight fraction, and Hm is the heat of fusion of 100 % crystalline PVA which is estimated as 150 J/g (Gupta et al., 2009). Results and Discussion Composite Mechanical Properties Composites prepared with 5% and 10% OPF bleched pulp, presented higher tensile strength which were 24.1 MPa and 26.7 MPa, respectively, compared to PVA film (23.6 MPa), and composite filled with 15% OPF bleached pulp (23.1 MPa). A low tensile strength of PVA composites filled with 15% OPF bleached pulp was assumed, connected with the filler agglomeration. It was highly possible, OPF bleached pulp agglomeration becomes concentrated in certain area of the composite, and weak the overall mechanical properties of the composite film % 10% 15% 5% 10% 15% 5% -5% 5%-10% 10%-5% PVA PVA-Pulp PVA-Agar PVA-Pulp-Agar Composites Figure 1. Composite tensile strength (MPa) The introduction of Agar at low content (5%) in the PVA composite was not

37 Modulus of elasticity (MPa) expected to reinforce the composite film. Instead, it was highly possible to become discontinue phase, and weak the overall mechanical properties of the composite film, which was 17.5 MPa. Agar at 10% and 15% content in PVA composites have not affected tensile properties of PVA film, as the composite tensile strength were 24.7 MPa and 22.2 MPa, respectively. Lyons et al. (2009) has developed Agar- PVA blend hydrogel with high level of Agar content. They reported that tensile strength of PVA with 60%, 70% and 80% of Agar were MPa; MPa; and MPa, respectively. It indicated that Agar can perform as reinforcement in PVA composites when introducted in high amount (more than 60% of total composite weight) and its reinforcing ability efficiency was reduced when used as much as 80% or more. Blending OPF bleached pulp and Agar in PVA composite was expected to produce composite film with high tensile strength. This research results showed that adding 5% OPF bleached pulp and 5% Agar into PVA matrix can increase PVA composite s tensile strength by 8.05%. However, the addition of 10% OPF bleached pulp and 5% Agar or 5% OPF bleached pulp and 10% Agar decreased the composite s tensile strength. Prachawarayakorn et al. (2012) has investigated the effect of Agar and cotton fibers on properties of thermoplastic wazy starch rice composites, using different ratios of Agar and cotton fibers, i.e. 0:0, 10:0, 8:2, 6:4, 4:6, 2:8 and 0:10. They reported that the highest stress at maximum load and Young s modulus was obtained from the waxy rice starch composite added by Agar and cotton fibers at the ratio of 4:6. This phenomenon is similar to our result. Although OPF pulp has the fibrous nature, introduction in higher amount of OPF pulp than that of Agar (ratio OPF pulp:agar = 10%:5%), produced PVA composite with lower tensile strength compared to PVA composites with equal amount of OPF pulp and Agar. PVA composite contained equal amount of OPF pulp and Agar showed higher tensile strength. It is assumed because OPF pulp and Agar were more dispersed in PVA matrix. The addition of OPF pulp, or Agar, or combination OPF pulp and Agar can 32 increase PVA composite s modulus of elacticity (MoE). OPF bleached pulp give more effect in composite MoE due to the fibrous nature of the OPF bleached pulp. In this research, as much of 10% OPF bleached pulp addition into PVA produced the highest composite MoE, which was MPa or % higher than of neat PVA MoE (94.0 MPa). The Agar addition into PVA matrix at same amount (10%) produces PVA composite with lower MOE, which was MPa or only % higher than of neat PVA. The influence of OPF bleached pulp fibrous nature on composite MoE is convinced by the higher value of PVA-Pulp-Agar composite s MoE with ratio Pulp:Agar = 10%:5%, than that of PVA-Pulp-Agar composite with ratio Pulp:Agar = 5%:10% % 10% 15% 5% 10% 15% 5% -5% 5%- 10% PVA PVA-Pulp PVA-Agar PVA-Pulp-Agar Composites 10%- 5% Figure 2. Composite modulus of elasticity (MPa) The large amount of hydroxyl groups on pulp fiber surfaces would form strong hydrogen bonding with PVA matrix in resulting a good adhesion at the fiber/pva interfaces (Cai et al., 2016). This leads to stress transfer from PVA to pulp fibers during stretching. After the composite was stretched to break, most of the embedded fibers were broken, while a few fibers which were nearly perpendicular to the stretching direction will be bend. The occurrence of fiber bowing is originated from the stress transfer, and in turn it improves the mechanical strength of the composites. Although the mechanical strength of pulp fibers/pva composites increased with fiber content, this improvement is not as significant as expected, in view of the large content of pulp fibers in composites and good adhesion at fiber/pva interfaces. This is believed to be due to poor uniaxial alignment of pulp fibers in the composites; and unfilled-niche defects within the composites, furthermore this type of defects grows with the fiber content (Tang and Liu, 2008).

38 Referring to composite reinforced with conventional fiber, highly aligned fibers instead of randomly oriented fibers would serve better in the manufacturing of fiber reinforced composites. New techniques need to be developed in order to decrease the unfilled pores/capillaries defects in the composite. By this way, the mechanical properties of composites can be further improved. It should be pointed out that the substantial increasing of MoE is not in accordance with the moderate gain of stress. This is because that the strain of the composite reduced largely even with a small fiber content in the composites, as found in the case that the strain of the composite with 15 wt% reinforcing fiber is about one-ninth of the neat PVA film. composite filled with 10% Agar was homogeneous with the grooved fracture surface, indicating of the phase compatibility between the PVA and Agar components. Black circle in Fig. 5b. showed that Agar could dispersed in PVA matrix, while yellow circle showed that in some places, PVA was agglomerated, indicated as bright area. Figure 4. Morphology of PVA-OPF bleached pulp composite 500 Max elongation (%) % 10% 15% 5% 10% 15% 5% -5% 5%- 10% PVA PVA-Pulp PVA-Agar PVA-Pulp-Agar Composite Figure 3. Composite maximum elongation (%) Composite Morphology 10%- 5% OPF bleached pulp could dispersed in PVA matrix, as shown in Fig. 4a (black circle). However, upon stretching to break, pulp fibers were pull out from PVA matrix as some OPF pulp fibers were showed at the edge of composite (Fig. 4b), suggesting the adhesion at the interface is not too strong. The pulp fibers need to be converted into a nanoscale of cellulose fibers to create a better adhesion with PVA as suggested by Tang and Liu (2008). The features of ultrafine diameter, high surface areas and hydrophilicity of cellulose nanofibers substantially enhanced the intermolecular interaction through forces such as hydrogen bonding at the interfaces of cellulose nanofiber/pva matrix (Tang and Liu, 2008). Morphology of PVA composites filled with 10% Agar as presented in Fig. 5a was examined by DinoLite microscope with 200x magnification. It was shown by Fig. 5a that the fractured surface of the PVA Figure 5. Morphology of PVA-Agar composite Composite Thermal Properties In this research, the melting temperature of PVA composite filled with OPF bleached pulp at concentration of 5%, 10% or 15% were lower than that of neat PVA. The crystallinity of PVA composite filled with 15% OPF bleached pulp was higher than that of neat PVA. The slight increase of crystallinity for PVA filled with 15 wt% OPF bleached pulp composite is possibly related to the nucleating effect of pulp fibers, which is previously observed in PVA/microfibrillated cellulose films (Lu, Wang and Drzal, 2008). Ollier, Perez and Alvarez (2013) reported that differential scanning calorymetry (DSC) experiments reveal an increase of the glass transition temperature of PVA composite as function of cellulose content, which could be related with the PVA-microcellulose interactions which restrict the capability of the matrix to move. Regardless the composition, there are no important changes on the melting temperature with the incorporation of cellulose microfibers. The melting point of PVA filled with 15% OPF bleached pulp was higher than 33

39 those of PVA-5% OPF bleached pulp and PVA-10% OPF bleached pulp (Fig. 6). The addition of OPF bleached pulp into PVA matrix, up to 10% do not effect the themal poperties of PVA. However, adding 15% OPF bleached pulp into PVA matrix could increase PVA composite melting point and also heat of fusion (Table 2). The higher of heat fusion in PVA-15% OPF bleached pulp, indicating a strong interfacial interaction between PVA and OPF bleached pulp. Since, Madera-Santana, Robledo and Freile-Pelegrín (2011) explained that an increase in ΔHmelt at higher concentrations of starch in PVA-Agar blends indicating a strong interfacial interaction between components. Thermal properties (melting temperature and heat of fusion) of PVA Agar composite films are shown in Fig. 7. An increase in melting temperature (Tm) was observed when 5% Agar was incorporated into the PVA matrix, then Tm decreased when 10% or 15% Agar was added. The decreasing of PVA composite melting temperature was also reported by Madera-Santana, Robledo and Freile- Pelegrín (2011). As Agar content in PVA composite is 50%, Tm is dropped off 45%. Melting temperature reached a minimum at this Agar concentration. Mucha and Pawlak (2005); Lewandowska (2009) also reported that the melting temperature decreased when chitosan was incorporated in PVAchitosan blends, attributable to a reduction in PVA crystallinity due to water presence on the macromolecular of composite. It is well known that thermal characteristics of PVA may vary with the degree of crystallinity and the amount of crystalline material (Peresin et al., 2010). In the PVA composite film with 10% or 15% Agar, melting temperature was lower than PVA composite film with 5% Agar. An effect of water presence is noticed since the presence of hydroxyl groups is identical with its hydrophilic characteristic. Addition of Agar into PVA matrix could break PVA intramolecular hydrogen bond and a reduction in hydrogen bonds shifted the crystalline regions of PVA. Heat of fusion or enthalpy (ΔHm) increased when 5% Agar was added into PVA matrix. The enthalpy of melting (ΔHm) also provides complementary information about physical bonding of the blending due to intermolecular hydrogen bonding. Madera-Santana, Robledo and Freile- Pelegrín (2011) showed an increase in ΔHmelt at higher concentrations of starch in PVA-Agar blends indicating a strong interfacial interaction between components. Prachayawarakorn et al. (2012) reported that the waxy rice starch composites modified by Agar (10:0) caused an increase in the onset decomposition temperature of starch. This could be described as the waxy rice starch matrix formed new hydrogen bond linkages with Agar. The inclusion of cotton fibers into the waxy rice starch matrix (0:10) also increased the onset degradation temperature of starch. The thermal stability of different waxy rice starch composites were significantly increased, as indicated by the decrease of percentage weight loss. On the other hand, no significant difference in weight loss was found for different waxy rice starch composites modified by different ratios of agar:cotton fibers. Figure 6. Thermogram of PVA-OPF bleached pulp composite 34

40 Figure 7. Thermogram of PVA-Agar composite Figure 8. Thermogram PVA-OPF bleached pulp and Agar composite In this research, addition of 5% OPF bleached pulp and 5% Agar into PVA matrix, decreased melting temperature and increase crytallinity of neat PVA (Fig. 8). Likewise, when the portion of OPF bleached pulp was added into PVA, the melting temperature was decreased more lower and the crystallinity was increased more higher. Instead of that, when the portion of Agar was added into PVA, the melting temperature was increased and the crystallinity was decreased, as presented in Table 2. The low melting temperature will reduce of the processing temperature and would become beneficial because lower temperature would avoid degradation of pulp fibers and polymer, and save energy. From that point of view PVA composite film filled with OPF bleached pulp is more potential to be developed industrially, compared to PVA composite film filled with agar powder. Table 2. Film composite thermal properties 35 Sample Composites Conclusion Tm Hm Xc [ C] [J.g -1 ] [%] PVA PVA+ bleached pulp 5% PVA+ bleached pulp 10% PVA+ bleached pulp 15% PVA+agar 5% PVA+agar 10% PVA+agar 15% PVA+agar 5% bleached pulp 5% PVA+agar 5% bleached pulp 10% PVA+agar 10% bleached pulp 5% Addition of OPF bleached pulp into PVA matrix results an improvement of composite mechanical properties, compared to addition of Agar powder. Hybrid composite with composition of 5% OPF bleached pulp and 5% Agar shows a higher mechanical properties compared to hybrid

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43 J.Lignocellulose Tech. 02 (2017), Journal of Lignocellulose Technology Journal homepage: Article Peningkatan mutu kayu dan kualitas kayu konstruksi dengan teknik pengasapan: kajian sifat kimia kayu dan keawetan terhadap jamur Schizophyllum commune Fries Lolyta Sisillia*, Farah Diba, Vitus Andri Forlius, Cristoporus Gita Piana Fakultas Kehutanan, Universitas Tanjungpura, Pontianak 78124, Kalimantan Barat Indonesia * Corresponding author: lolytasisillia@yahoo.co.id Received:15 November Received in revised form: 18 December 2017 Accepted: 20 December Published online: 29 December 2017 Abstract Wood used as raw material for construction in West Kalimantan has decrease due to limited qualifications of wood. Efforts to improve the quality of wood for construction materials are important to undertake. The objective of the research is to improve the quality of wood construction by fumigation technique. A specific objective is to assess the effect of fumigation technique on chemical properties of wood and wood durability against the Schizophyllum commune fungi. The treatment consist two kinds of wood, i.e. Akasia wood (Acacia mangium Willd) and Laban wood (Vitex pubescens Vahl). The chemical analysis used TAPPI standard and testing the durability to fungi based on SNI standard. The result of research showed that the average value of extractives of Laban wood after fumigation method was increase, both on extractives soluble on cold water, soluble on hot water and soluble on alcohol benzene, with value 7.62%, 9.16% and 7.30%. The value of cellulose on Akasia and Laban wood after the fumigation process was increase. The average value of Akasia wood cellulose was 44.15% and in Laban wood it was 45.07%. Meanwhile on control wood, the average value of cellulose of Akasia was 43.18% and in Laban wood was 43.76%. The durability of Akasia and Laban wood after fumigation was increase. The average weight loss was 9.55% on Akasia wood and 8.03% on Laban wood. The fumigation treatment can improve the quality of construction timber, particularly on the chemical nature of wood and the durability of wood. Keywords : Acacia mangium, fumigation, Schizophyllum commune, Vitex pubescens, wood construction Pendahuluan Penggunaan kayu sebagai bahan konstruksi bangunan harus memenuhi syarat mampu menahan beban dalam jangka waktu yang direncanakan, memiliki ketahanan dan keawetan yang memadai melebihi umur pakainya. Konstruksi bangunan akan kuat, tahan dan awet apabila kayu yang digunakan adalah kayu yang kuat juga tahan terhadap serangan organisme perusak kayu. Saat ini harga kayu yang memiliki kekuatan dan keawetan tinggi semakin mahal karena 38

44 persediaan kayu kuat dan awet dari alam semakin berkurang. Pemilihan kayu campuran dari kelas kuat dan awet yang lebih rendah seperti kayu Laban, Akasia, Meranti, Nyatoh dan Medang untuk bahan baku konstruksi bangunan menjadi lazim dilakukan oleh penduduk di Provinsi Kalimantan Barat. Hal ini disebabkan harga kayu tersebut lebih murah, pasokan kayu masih banyak, serta memiliki corak dan warna yang cukup menarik. Jenis kayu yang tergolong kuat tetapi memiliki kelas awet III artinya kayu tersebut memiliki kekuatan yang cukup baik untuk konstruksi bangunan tetapi mudah diserang oleh organisme perusak kayu seperti jamur dan umur pakainya cukup singkat apabila berhubungan dengan tanah lembab dan pengaruh cuaca. Penggunaan kayu tersebut untuk bahan konstruksi perlu perlakuan pengawetan untuk meningkatkan mutu kayu. Upaya peningkatan keawetan kayu dapat dilakukan dengan cara pengasapan. Hasil penelitian Sisillia dan Setyawati (2015) menyatakan pengasapan secara tradisional terhadap kayu Karet mampu meningkatkan kualitas sifat mekanik (keteguhan lentur statis, keteguhan patah, dan keteguhan tekan sejajar serat) dibandingkan dengan kayu Karet yang tidak diasapkan. Hasil penelitian Sisillia dan Diba (2015) menunjukkan bahwa teknik pengasapan secara tradisional mampu meningkatkan ketahanan kayu Akasia dan Laban sebagai bahan baku kerajinan terhadap serangan rayap kayu kering dan rayap tanah. Pengasapan juga membuat kayu memiliki nilai dekoratif yang khas, yakni kayu berwarna lebih gelap. Pengasapan merupakan cara pengawetan kayu dengan memanfaatkan kombinasi perlakuan pengeringan dan pemberian senyawa kimia alami dari hasil pembakaran bahan bakar. Panas yang dihasilkan dari pembakaran kayu menyebabkan terjadinya proses pengeringan. Senyawa asam organik dalam asap memberikan warna. Fenol dan formaldehid membentuk lapisan damar sehingga produk menjadi mengkilap. Todd (2002) menyatakan proses pengasapan menyebabkan perubahan pada komponen kimia kayu seperti lignin, selulosa dan hemiselulosa. Gas organik yang terdapat pada asap menyebabkan kayu berubah warna menjadi lebih gelap. Hasbullah (2013) menyatakan asap dari pembakaran kayu mengandung senyawa fenol dan formaldehida yang bersifat fungisida dan bakterisida.tujuan penelitian adalah untuk mengetahui pengaruh pengasapan terhadap komponen kimia kayu serta sifat keawetan kayu Laban (Vitex pubescens Vahl) dan kayu Akasia (Acacia mangium Willd) dari serangan jamur pelapuk kayu. Bahan dan Metode Bahan dan Alat Bahan yang digunakan dalam penelitian adalah kayu Akasia (A. mangium) dan kayu Laban (V. pubescens), berasal dari hutan sekunder Kabupaten Bengkayang Provinsi Kalimantan Barat. Pohon Laban memiliki diameter 20 cm dan pohon Akasia memiliki diameter 17 cm. Jamur Schizophyllum commune diperoleh dari biakan jamur Laboratorium Teknologi Hasil Hutan Fakultas Kehutanan Universitas Tanjungpura. Media pertumbuhan jamur adalah PDA. Alat yang digunakan adalah alat pengasapan kayu,waterbath, dan botol uji jamur. Persiapan Contoh Uji Kayu Contoh uji kayu untuk menganalisis perubahan warna berukuran 2 cm x 2 cm x 4 cm. Contoh uji untuk analisis sifat kimia kayu adalah serbuk kayu dengan ukuran lolos saringan 40 mesh tertahan 60 mesh. Contoh uji kayu untuk pengujian keawetan terhadap jamur mengacu pada SNI tentang Uji Ketahanan Kayu dan Produk Kayu Terhadap Organisme Perusak Kayu. Contoh uji berukuran 5 cm x 2,5 cm x 1,5 cm. Perlakuan penelitian adalah kayu yang diasapkan dan kayu yang tidak diasapkan. Masing-masing sampel kayu dibuat tiga ulangan Kayu yang menjadi sampel pengujian berada dalam kondisi kering udara. Pengasapan Kayu Pengasapan kayu Akasia dan Laban menggunakan tungku dengan bahan bakar dari tempurung kelapa. Proses pengasapan kayu dilakukan selama tiga jam pada pagi hari pukul wib dan tiga jam pada sore hari pukul wib selama dua pekan. Analisis Warna Kayu Perbedaan warna yang terjadi setelah pengasapan dianalisa dengan Munsell soil color dan CIElab. Contoh uji yang telah 39

45 diasapkan dan yang tidak diasapkan discan dan diamati nilai warna yang muncul. Data diolah dengan software Adobe Photoshop CS3 menghasilkan nilai L*, a* dan b*. Perbedaan warna ( E) dihitung berdasarkan metode CIELab (Christie 2007), dengan rumus : E = [( L )² + ( a )² + ( b )²] (1) E = Perbedaan warna L = Perbedaan kecerahan = L*contoh uji-l*kontrol a* = Perbedaan merah atau hijau = a*contoh uji-a*kontrol b* = Perbedaan kuning atau biru = b*contoh uji-b*control Analisis sifat kimia kayu dan uji jamur Pengujian sifat kimia kayu Akasia dan kayu Laban berdasarkan standar TAPPI. Sifat kimia kayu yang dianalisis meliputi kadar zat ekstraktif larut air dingin, air panas dan larut alkohol benzene dan kadar selulosa. Pengujian keawetan terhadap jamur dilakukan dengan meletakkan kayu sampel pada media PDA yang sudah berisi biakan jamur S. commune. Selanjutnya media disimpan dalam inkubator pada suhu ruang selama tiga bulan. Selanjutnya dihitung nilai kehilangan berat sampel karena serangan jamur. Persentase kehilangan berat kayu didapatkan dengan rumus : WL (%) = W 1 W 2 W 1 x100 (2) WL: Kehilangan berat contoh uji (%) W1: berat contoh uji mula-mula W2: berat contoh uji setelah diserang jamur Hasil dan Pembahasan Nilai Perubahan Warna Kayu Warna sampel kayu yang diasapkan dan tidak diasap diukur menggunakan Munsell Soil Color Chart. Hasil penelitian menunjukkan perbedaan warna yang signifikan. Disamping itu kayu Laban dan kayu Akasia yang diasapkan menghasilkan tekstur kayu yang halus, warna agak mengkilap dan kesan rabanya menjadi licin. Warna kayu Laban dan Akasia sebelum dan setelah pengasapan disajikan pada Tabel 1. Tabel 1. Klasifikasi warna kayu Laban dan Akasia sebelum dan setelah diasapkan menggunakan Munsell Soil Color Chart No Kayu Warna Kayu Warna 1 Kayu Laban kontrol Kayu Laban diasapkan 7/3 Very pale brown 2/2 Very dark brown 2 Kayu Akasia kontrol Warna Kayu Akasia diasapkan Warna 6/3 Pale brown 3/2 Very dark gray brown Hasil analisis perubahan warna sampel kayu yang diasapkan dan tidak diasap menunjukkan nilai perbedaan warna ( E) rata-rata kayu Laban sebesar 35,35 sedangkan pada kayu Akasia sebesar 32,67. Kayu Laban yang telah diasapkan menghasilkan nilai rata-rata L* sebesar 36,88, nilai a* sebesar 18,80 dan nilai b* sebesar 15,03. Kayu Akasia yang telah diasapkan menghasilkan nilai rata-rata L* sebesar 43,10, nilai a* sebesar 18,10 dan nilai b* sebesar 25,00. Kayu Laban kontrol 40 memiliki nilai rata-rata L* sebesar 70,14 sedangkan kayu Laban yang diasapkan memiliki nilai rata-rata L* sebesar 36,88 (turun 47,41%). Semakin turun/kecil nilai L* maka tingkat kecerahan kayu akan semakin rendah (warna kayu semakin gelap). Demikian pula pada kayu Akasia kontrol memiliki nilai rata-rata L* sebesar 74,25 sedangkan kayu Akasia yang diasapkan memiliki nilai rata-rata L* sebesar 43,10 (turun 41,95%).

46 Nilai rata-rata a* pada kayu Laban kontrol sebesar 8,36 dan meningkat pada kayu Laban yang diasapkan sebesar 18,80 (naik 55,53%). Nilai rata-rata b* pada kayu Laban kontrol sebesar 9,88 dan meningkat pada kayu Laban yang diasapkan sebesar 15,03 (naik 34,26%). Semakin naik nilai a* dan b* maka komposisi warna merah dan kuning di dalam warna kayu Laban menyebabkan hasil pewarnaan kayu menjadi lebih gelap. Hal yang sama terjadi pada kayu Akasia. Nilai rata-rata a* pada kayu Akasia kontrol sebesar 11,25 dan meningkat pada kayu Akasia yang diasapkan sebesar 18,10 (naik 37,84%). Nilai rata-rata b* pada kayu Akasia kontrol sebesar 19,70 dan meningkat pada kayu Akasia yang diasapkan sebesar 25,00 (naik 26,00%). Pengasapan menghasilkan warna kayu yang lebih gelap. Asap yang terserap ke dalam kayu diduga berikatan hidrogen dengan gugus hidroksil pada komponen kimia kayu (Sunarto, 2008). Nilai perbedaan warna ( E) kayu Laban dan kayu Akasia setelah diasapkan disajikan pada Gambar 1. hanya pada zat ekstraktif larut dalam alkohol benzene yang nilainya lebih tinggi. Zat ekstraktif larut air dingin dimaksudkan untuk melarutkan zat ekstraktif seperti tanin, gula, garam atau zat perwarna kayu (Sjostrom, 1998). Hasil penelitian menunjukkan zat ekstraktif larut dalam air dingin kayu Akasia kontrol sebesar 4,88%. Nilai zat ekstraktif ini lebih tinggi daripada hasil penelitian Malik dkk. (2010). Zat ekstraktif kayu termasuk kelas tinggi jika kadar ekstraktif lebih besar dari 4%, kelas sedang jika kadar ekstraktif 2-4%, dan kelas rendah jika kadar ekstraktif kurang dari 2% (Fengel dan Wegener, 1995). Nilai zat ekstraktif kayu Laban dan kayu Akasia termasuk dalam klasifikasi kelas tinggi karena memiliki nilai rata-rata lebih dari 4%. E ulangan Gambar 2. Nilai rerata zat ekstraktif larut dalam air dingin, larut dalam air panas dan larut dalam alkohol benzene pada kayu Laban dan kayu Akasia yang diasapkan dan tidak diasapkan Gambar 1. Perbedaan warna ( E) kayu Laban dan kayu Akasia setelah diasapkan Sifat kimia kayu Zat ekstraktif Nilai rerata zat ekstraktif larut air dingin, larut air panas dan larut dalam alkohol benzene kayu Laban yang diasapkan sebesar 7,3% ~ 9,16% sementara pada kayu Akasia yang diasapkan sebesar 3,29% ~ 8,14%. Nilai rerata zat ekstraktif larut air dingin, larut air panas dan larut dalam alkohol benzene untuk kayu Laban yang diasapkan lebih tinggi daripada kayu Laban kontrol. Namun pada kayu Akasia nilai rerata zat ekstraktif larut air dingin dan larut air panas pada kayu yang diasapkan lebih rendah daripada kayu Akasia kontrol, Selulosa Nilai rerata selulosa kayu Laban yang tidak diasapkan sebesar 43,76%, sedangkan pada kayu yang diasapkan sebesar 45,07%. Nilai rerata selulosa kayu Akasia yang tidak diasapkan sebesar 43,18%, sedangkan pada kayu yang diasapkan sebesar 44,15%. Nilai rerata selulosa kayu Laban dan kayu Akasia yang diasapkan lebih tinggi daripada kayu kontrol. Toledo (2007) menyatakan proses pengasapan akan meningkatkan kandungan fenol pada kayu. Hal ini dapat meningkatkan kandungan selulosa dan lignin. Peningkatan kandungan lignin membuat kayu dapat digunakan sebagai bahan baku konstruksi. Nilai rerata selulosa kayu Laban dan kayu Akasia yang diberikan perlakuan pengaspaan disajikan pada Gambar 3. 41

47 Gambar 3. Nilai rerata selulosa kayu Laban dan kayu Akasia yang diasapkan dan tidak diasapkan Ketahanan kayu terhadap jamur S. commune Nilai rerata Nilai kehilangan berat kayu akibat serangan jamur S. commune sebesar 21,68% pada kayu Laban dan 13,75% pada Kayu Akasia yang tidak diasapkan. Sementara itu pada kayu Laban dan kayu Akasia yang diasapkan nilai kehilangan berat akibat serangan jamur lebih kecil, yaitu masing-masing sebesar 8,03% untuk kayu Laban dan 9,55% untuk kayu Akasia. Kurniawan (2011) menyatakan kulit kayu Laban mengandung flavonoid dan terpenoid yang merupakan senyawa yang tahan terhadap serangan jamur. Hasil analisis ragam menunjukkan perlakuan pengasapan berpengaruh sangat nyata terhadap nilai kehilangan berat kayu akibat serangan jamur. Nilai kehilangan berat kayu Laban dan Akasia karena serangan jamur S. commune disajikan pada Gambar 4. Gambar 4. Nilai rerata kehilangan berat kayu Laban dan kayu Akasia yang diasapkan dan tidak diasapkan karena serangan jamur S. commune Fries Hasil penelitian diperoleh nilai ratarata kehilangan berat kayu Akasia yang tidak diasapkan sebesar 13,75% dan Kayu Laban yang tidak diasapkan sebesar 21,68%, termasuk dalam kategori IV atau 42 tidak tahan. Nilai kehilangan berat kayu Laban yang diasapkan sebesar 8,03% dan pada kayu Akasia sebesar 9,55%, termasuk dalam kategori kelas III atau agak tahan. Klasifikasi keawetan mengacu kepada SNI tentang kehilangan berat kayu karena serangan jamur S. commune. Perbedaan serangan jamur pada perlakuan kayu yang diasapkan dan tidak diasapkan diakibatkan jumlah kandungan fenol dan asam asetat yang terdapat pada kayu. Fenol dan asam asetat diserap kayu dari jamur. Perlakuan pengasapan meningkatkan kelas ketahanan kayu terhadap jamur. Kayu Laban dan kayu Akasia yang akan digunakan sebagai bahan konstruksi diharapkan tidak mudah terserang oleh jamur. Ouypornprasert et al. (2005) menyatakan kayu Akasia khususnya A. mangium Willd baik digunakan sebagai bahan baku kayu konstruksi. Sisillia dan Diba (2016) menyatakan perlakuan pengasapan secara tradisional meningkatkan sifat fisik dan mekanik kayu Laban dan kayu Akasia. Pengasapan menghasilkan kayu yang berwarna lebih gelap disebabkan kayu menyerap asap pada proses pengasapan. Menurut Oramahi et al. (2014) asap dari proses pembakaran mengandung fenol dan asam asetat yang dapat menghambat serangan rayap dan jamur. Kesimpulan Nilai perbedaan warna ( E) rata-rata kayu Laban sebesar 35,35 dan pada kayu Akasia sebesar 32,67. Warna kayu berubah dari coklat muda menjadi coklat gelap. Perlakuan pengasapan kayu Laban menghasilkan nilai zat ekstraktif larut air dingin, larut air panas dan larut dalam alkohol benzene yang lebih tinggi, sebesar 7,3% ~ 9,16% sementara pada kayu Akasia yang diasapkan sebesar 3,29% ~ 8,14%. Nilai rerata selulosa kayu Laban yang diasapkan sebesar 45,07% sedangkan pada kayu Akasia 44,15%. Kelas ketahanan kayu Laban dan Akasia yang diasapkan terhadap jamur S. commune meningkat dari kelas IV menjadi kelas III dan termasuk dalam kategori tahan terhadap serangan jamur. Ucapan Terima Kasih Penulis menyampaikan terima kasih kepada Kementerian Riset, Teknologi dan Pendidikan Tinggi, Direktorat Riset dan Pengabdian Masyarakat DIKTI yang telah

48 memberikan dana penelitian melalui Skim Penelitian Terapan tahun Daftar Pustaka Christie, R.M. (2007). Colour Chemistry. Cambridge [GB]: The Royal Society of Chemistry Science Park. Hasbullah. (2013). Daging Asap (Daging Sale) Cara Tradisional. Dewan Ilmu Pengetahuan, Teknologi dan Industri Sumatera Barat. [diakses 28 Agustus 2017]. Fengel, D dan Wegener, G. (1995). Kayu: Kimia, Ultrastruktur, Reaksi-reaksi. penerjemah Hardjono S, Soenardi P, penyunting. Gadjah Mada University Press. Yogyakarta. Hunter Lab. (2008). Hunter Lab ColorScale. [diakses pada 25 Agustus 2017] Malik, J., Santoso, A. dan Rachman, O. (2005). Sari Hasil Penelitian Mangium (Acacia mangium Willd.). Kurniawan, D. (2011). Pemanfaatan Ekstrak Kulit Laban (Vitex pubescens Vahl.) Sebagai Bahan Anti Jamur. Journal of Food Protection, 55, pp Oramahi, H.A., Diba, F. dan Nurhaida. (2014). New Bio Preservatives from Lignocelluloses Biomass Bio-oil for Anti termites Coptotermes curvignathus Holmgren. Procedia Environmental Sciences Journal, 20, pp Ouypornprasert, W., Boonyachut, S. dan Boonyachut, S. (2005). Acacia mangium Willd as Structural Components and Shear Walls. International Journal of Materials & Structural Reliability, 3(2), pp Sisillia, L. dan Diba, F. (2015). Teknik Pengasapan Kayu untuk Peningkatan Mutu Kerajinan Kayu Khas Kalimantan Barat: Kajian Keawetan Kayu terhadap Rayap. Dalam: Proseding Seminar Nasional MAPEKI XVIII. Bandung, Indonesia, 4-5 November Sisillia, L. dan Setyawati, D. (2015). Peningkatan Sifat Fisik dan Mekanik Kayu Karet (Hevea brasiliensis) dengan Metode Pengasapan. Laporan Penelitian Dosen Muda. Fakultas Kehutanan Universitas Tanjungpura Sisillia, L. dan Diba, F. (2016). Effect of Traditional Fumigation on Pysical, Mechanical and Anatomy Properties of Wood as Material of Handicraft. Wood Research Journal, Journal of Indonesian Wood research Society, 7(1). Sjostrom, E. (1998). Kimia Kayu, Dasar-dasar dan Penggunaan. Sastrohamidjojo H, penerjemah; Prawirohatmodjo S, editor. Gajahmada University Press. Yogyakarta. Terjemahan dari: Wood Chemistry, Fundamentals and Applications. SNI (2006). Uji Ketahanan Kayu dan Produk Kayu Terhadap Organisme Perusak Kayu. Badan Standarsasi Nasional.SNI. Jakarta Sunarto. (2008). Teknik Pencelupan dan Pencapan. Departemen Pendidikan Nasional. Jakarta. TAPPI TAPPI Test Methods. TAPPI Press. Atlanta. Todd, J. (2002). Wood-Smoke Handbook: Woodheaters. Firewood and Operator Practice. Department of the Environment and Heritage. Australia 43

49 J.Lignocellulose Tech. 02 (2017), Journal of Lignocellulose Technology Journal homepage: Article Characterization palm kernel caked and its application in making board composite Miranti Maya Sylvani *, Nanda Andrian Yuditya Departemen Kimia, Fakultas Matematika dan Ilmu Pengetahuan Alam, Institut Pertanian Bogor, Jl. Tanjung Kampus IPB Dramaga, Bogor, *Corresponding author : mirantimayasylvani@yahoo.com Received:11 Maret Received in revised form: 15 September 2017 Accepted: 1 December Published online: 29 Desember 2017 Abstract The aim of this research is to characterize Palm Kernel Caked (PKC) which are and are not NaOH-treated and the application by making the composite board. The characterization of PKC has been done by using cellulose analysis, fouriertransform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Delignification occured in the PKC treated NaOH which proved by the presence of peak at cm -1. At o C, the melting point of PKC shows that the making of composite board by using extruder at 150 o C would not occur degadration. The difference of method and the usage of coupling agent (MAPP). Based on water absorbency and density, the making of composite board by using extruder is better than by using hot plate which is supported by the homogenity and inexistence of pore in the composite board. In the other hand, the treatment of MAPP show better result in the making of composite board than the nontreated one because the presence of esteric bond between OH and anhydric in MAPP causing barrier to the water flow. Keywords : palm kernel caked, alkaline, extruder, MAPP Introduction In 2012, the area of palm oil tree plantation in Indonesia reachs 9.2 million hectares, which consisted 59.12% industrial plantation and 40.88% home plantation (BPS, 2013). The rapid development places Indonesia as the largest palm oil producer in the world. Palm kernel caked (PKC) is formed as a side product from the processing of palm oil, which could be separated by using chemical or physical separation as we could see at Fig. 1. The maximum amount of PKC in every single Number of coconut core oil cakes sawit reachs 3.5% from every processed palm oil bunch (TBS). Usually, PKC is used for feed (Nurhayati, Sjofjan and Koentjoko, 2006) Figure 1. The formation of Palm Kernel Caked (PKC) 44

50 Lignocellulose is also contains in PKC. The amount of Iignocellulose in PKC consisted of cellulose (11.6%) and hemicellulose (61.5%), including xylan (37%) and mannan (57.8%) (Nadia et al., 2016). Hence, PKC also fulfills the conditions for further process of composite board. Composite board is the combination of two or more material united by a matrix, which is polymer. Based on the formation bond, polymer is divided into 2 groups, thermoplastic and thermoset. The usage of thermoplastics such as polypropylene at composite board could bring an advantages which is environmental friendly because it reduce the usage of plastic. Ministry of Environment and Forestry of Indonesia express that plastic waste amounts could reachs 26,500 tons per day. PKC s filler could not mix easily with thermoplastic such as polypropylene (PP) because the low of compatibility and composite interface adhesion. Therefore, one or other way of interfacial adhesion between PKC and PP is by modifying the surfance of filler, with additional of NaOH and MAPP. The aims of this research are to identify alkaline modification at PKC and the application at composite board. Before PKC has been poured, make sure 20% of PP are melted. PP and PKC are mixed by using hot plate at 150 O C. c) PP and PKC are mixed with MAPP 3% by using hot plate. During composite board forming process, the distribution of material have to be done equally. Mechanic and physical characterization includes density, water absorption and SEM analysis. Examination of physical properties is done based on standard JIS A 5908: Particleboard. Results and Discussion The influence of alkaline PKC Dark brown PKC is required after alkaline treatment was carried out, meanwhile the PKC which didn t carry the alkaline treatment has the light brown one, which are presented in Fig. 2. The main reason is the ability of NaOH which could decrease the bond strength between cellulose and lignin, pectin and hemicellulose so that the brightness is increased. The delignification s mechanism by NaOH solution is present in Fig. 4. The alkaline treatment could increase pureness of cellulose. Materials and Method Materials The material in this research are: Palm Kernel Caked (PKC) which is provided from PTPN North Sumatera, Indonesia, Polypropylene (PP), NaOH, aquades. Maleat anhydrate polypropylene (MAPP) is acted as a glue. The modification and characterization of PKC Ten g of PKC are cellulose analysed and characterized by using Chesson Method, functional group analysis by using FTIR and melting point analysis with DSC. 25 g of PKC are dissolved in 250 ml NaOH 55 mm, then carefully add NaOH 2M until the ph reach 13. Then, the solution are filtered and the powder are be dry by using oven in 100 O C, 3 hours. Dried powder then be cellulose analyze by using Chesson method and functional group identification by using FTIR. Making of composite board by using hot plate, extruder, and adding MAPP Figure 2. Physical analysis of palm kernel caked a) with NaOH b) without NaOH Figure 3. Analysis of cellulose to palm kernel caked (PKC) By using ratio (PKC:PP) 10:20, those materials packed into extruder at 150 O C. 45

51 PKC, the amount of lignin and fibre is decreased. The FTIR spectrum in Fig. 5 shows that the powder of alkaline-treated PKC has a hydroxyl group and C-H group which are represented at cm -1 and cm -1. Figure 4. Disconnection of a bond between lignines and cellulose by NaOH (Ismail and Farsi, 2010) Fig. 3 shows that seen the amount of cellulose in NaOH-treated PKC is lower (23.21%) than the treated one (28.31%). In the other hand, the texture of alkalinetreated PKC is more rough than the untreated one. The modification of alkaline treatment would break the hydrogen bond causing the surface getting more rough. The absence of hydroxyl group and the presence of C-H at cm -1 at untreated PKC are showed in Fig. 5. After the alkaline treatment was carried out in The result showed that the effectiveness of treatment from NaOH can broken lignin so that lignin raveled and cellulose doesn t protected to be cellulose easy to accessed. From the making of composite board, alkaline treatment technique at cellulose fibre is modifying by chemistry. It has been done to increase adhesion between surfaces of cellulose fibre and polymer like has been done (Nor et al, 2014; Fatimah et al., 2015). The melting point characterization showed in Fig. 6 which explained that the PKC s melting point is C. According to Fig. 6, PKC is fulfill the specification for extrusion at 150 o C so that the material could not easily melt. Figure 5. Disconnection of a bond between lignines and cellulose by NaOH (Ismail and Farsi, 2010) 46

52 DSC C H e a t F l o w / m W J/g C C T e m p e r a t u r e / C +00 Figure 6. Thermal analysis of Palm Kernel Caked without NaOH use DSC The formation of composite board from PP-treated PKC with different methods gave different result. In this case, the composite board which has been made by using extruder showed bright and glossy colour. The PKC s powder distribute equally between the polymer according to Fig. 7. Meanwhile the surface of composite board was being held, it felt At the time of groped, surface of composite board felt is smooth and slippery. In the other hand, the composite board which has been made by using hot plate, has a inversed result. There are 2 types of system in composite board formation, such as batch system, which need a hot plate and continue system, which need an extruder. The extruder would carry an extrusion process. Febrianto et al. (2005) reported that extrusion is combination of heat, pressure, friction, and temperature simultaniously in a rotating screw. Extrusion has some advantages, which is less-time consuming and adjustable heat which have been done by Yudhi et al. (2017). Water absorbtion showed that the composite board which have been made by using extruder is more clear than the other one which been made by hot plate. SEM characterization provided information that occured a homogenity between PKC and PP while the board was being form and there is no pore on the board s surface of the board which 47 explained the strength between matrix and filler. The homogenity of PKC-PP s board is indicated by the layer PKC covering PP s layer, even tough not all of the PKC s layer succesfully covered the PP s layer caused by the ratio 1:2 (PKC:PP). However, the good homogenity indicated by its visual which there is no porosity and particle boundary. The water absorptivity and density is commonly related. The composite board which been made by using extruder, has lower water absortivity value (5.36%) than the other which been made by using hot plate (18.08%). In the other hand, the density value has an inverse result, 0.83 g/cm 3 or the composite board which have been made by using extruder and 0.62 g/cm 3 by using hot plate. Figure 7. Physical analysis of composite board extruder The result of this research shows that the density of composite board which is made by using hot plate is directly

53 accorded with JIS A particleboards type 13 as a standard with density value 0,4-0,9 (g/cm 3 ) while composite board which is made by using extruder with JIS A hardboard S20 as a standard, is 0,8 (g/cm 3 ). Figure 10. DSA and density of composite board with different of method Figure 8. Morphology of the fault surface from PP/PKC (using extruder) with enlargement 100x The water absorbency of MAPP-added composite board (18.08%) is lower than the not-treated one (22.58%). However, the density of MAPP-added composite board (0.65 g/cm 3 ) is higher than the not-treated one (0.62 g/cm 3 ). Maleic anhydric as binding agent generally has been used to increase strength of composite board (Hua et al., 2012). Zhou and Yu (2013) reported that the addition of coupling agent can increase the number of esteric-bond between filler s hydroxyl group and MAPP s carboxyl group, hence it could decrease the ability of water absorption. Figure 9. Surface morphologies of front from PP/PKC (applies extruder) with enlargement 100X Liqing et al. (2013) reported that the water absorbtivity at composite board is caused by the existence of hydrogen bond formed between filler s hydroxyl group with water. Ika and Destika (2015) expressed the existence of pores would caused an water interaction. Figure 11. DSA and density of composite board with or without MAPP addition Making of Composite Board with or doesn't Apply MAPP Maloney (1993) reported that the density has an equal proportion with the cohesivity of intermolecular hence the airspaces inside the composite board is getting smaller. This situation caused difficulties for water to fill the airspaces, which means, the density has an inversely proportion with water absorption. Figure 12. Fibre mechanisme of reactions with PP-G-MA (Hua et al., 2012) 48