2006 64 Vol. 64, 2006 8, 756 760 ACTA CHIMICA SINICA No. 8, 756 760 * ( 200092) ( ). BET,...,., / [n( ) n( ) 2]. ; ; ; ; Synthesis of Mesoporous Silica Materials Using the Reactive Urea-formaldehyde Resin Polymerized in situ as Template GUO, Bin LIU, Hui HAO, Zhi-Xian* GAN, Li-Hua XU, Zi-Jie CHEN, Long-Wu (Department of Chemistry, Tongji University, Shanghai 200092) Abstract A simple one-step procedure was described for the synthesis of mesoporous monolith and composite sphere, in which hydrolyzation of tetraethyl orthosilicate and polymerization of urea with formaldehyde occurred at the same time. The analysis of the liquid nitrogen adsorption demonstrated that the pore sizes of the monoliths and the composite spheres were both uniform. Morphologies of the composite spheres characterized by SEM were smooth or of network, which depended on the relative concentrations of the reactants. As the molar ratio of formaldehyde to urea exceeded the limit of 2.0, the synthesis by varying initial concentration of the reactants yielded the monoliths with controllable pore sizes. From the analysis of the FTIR and DTA, the urea-formaldehyde resin with branched chains in its molecular structure was considered as an inducing agent in the pore formation of the monolith. Keywords mesoporous silica; template; urea-formaldehyde resin; composite powder; monolith [1 5]. 1992 Mobile MCM- 41 [6],,. ( [7] ),,, [8 10]., [1 6,8 11], * E-mail: haozhixian@mail.tongji.edu.cn Received June 24, 2005; revised November 8, 2005; accepted December 21, 2005. (No. 1380219043).
No. 8 757, D- D- -L- [12] ; [13] ; ( [14] [15] [16] ). -ZrO 2 -TiO 2, [17]., [18] 4 µm. Arafa [19],...,. 1 1.1 : (, 98.5%, ); (, 99.7%, ); (, 99.0%, ); (, 37.0% 40.0%,, 38.0% ); (, 36.0% 38.0%,, 37.0% ),. 1.2 0.40 ml 50 ml 15 ml (TEOS) 20 ml 50 ml, n(teos) n(hcl) n(h 2 O) n(etoh) 1.0 0.070 83 5.0. 2 h,, 20 min, 20 h., 55, ph 2. 30 min., 70 2 d., 90 2 d,., 60 70 2 d. 600, 2 h. 1.3 Thermo Nicolet NEXUS ; CDR-1 ; Micromeritics Tristar 3000 ; Philips XL-30 (20 kv). 2 (U) (TEOS) 1.0 1.6, (F), 1,. 1 Table 1 Molar ratios of reactants and the weight of composite sphere n( ) n( ) n(teos) /g F 0.0 U 1.0 S 1.6 0.0 1.0 1.6 0.000 F 0.5 U 1.0 S 1.6 0.5 1.0 1.6 1.105 F 1.0 U 1.0 S 1.6 1.0 1.0 1.6 2.440 F 1.5 U 1.0 S 1.6 1.5 1.0 1.6 2.417 F 2.0 U 1.0 S 1.6 2.0 1.0 1.6 0.000 F 3.0 U 1.0 S 1.6 3.0 1.0 1.6 0.000 F 4.0 U 1.0 S 1.6 4.0 1.0 1.6 0.000 F 9.0 U 3.0 S 1.6 9.0 3.0 1.6 0.556 1., 0.0 1.0 1.0 1.0 2.0 1.0. 1.0 1.0. 3.0 1.0 3.0 1.6.,.
758 Vol. 64, 2006 2.1 BET 600 SiO 2 6 nm, 680 m 2 /g, 1.0 cm 3 /g, 50 m 2 /g., 90,. 2 BET. 1.0 1.0 3.0 1.0,. 2 BET Table 2 BET characterization data of the monolith silicas synthesized with two different molar ratios of formaldehyde to urea a / nm / (m 2 g 1 ) / (m 2 g 1 ) / (cm 3 g 1 ) F 0.27 U 0.27 S 1.6 13.45 301.3 8.1 1.013 F 0.53 U 0.53 S 1.6 15.86 285.5 8.4 1.133 F 1.0 U 1.0 S 1.6 15.15 292.6 5.8 1.108 F 1.6 U 1.6 S 1.6 13.91 295.7 4.4 1.028 F 0.81 U 0.27 S 1.6 11.77 329.0 0.968 F 1.6 U 0.53 S 1.6 11.42 331.2 0.946 F 3.0 U 1.0 S 1.6 7.28 460.2 0.838 F 4.8 U 1.6 S 1.6 5.51 540.9 0.745 460 m 2 /g, 0.41 0.84 cm 3 /g, F 1.0 U 1.0 - S 1.6. Wang [20],. 1 F 1.0 U 1.0 S 1.6 BJH Figure 1 BJH pore size distributions of F 1.0 U 1.0 S 1.6 (a) before calcination; (b) after calcination a 1,. 2 1.0 1.0,, 14 nm, 290 m 2 /g, 1.1 cm 3 /g ; 3.0 1.0,, 11.77 nm 5.51 nm, 329.0 m 2 /g 540.9 m 2 /g, 0.9679 cm 3 /g 0.7453 cm 3 /g. 3.0 1.0. 1 2 F 1.0 U 1.0 S 1.6 F 4.8 U 1.6 S 1.6. 190 300. F 4.8 U 1.6 S 1.6 F 1.0 U 1.0 S 1.6, F 4.8 U 1.6 S 1.6 F 1.0 U 1.0 S 1.6. BET, F 1.0 U 1.0 S 1.6 261 292 m 2 /g, 1.00 1.10 cm 3 /g,. F 4.8 U 1.6 S 1.6 202 2 F 4.8 U 1.0 S 1.6 BJH Figure 2 BJH pore size distributions of F 4.8 U 1.0 S 1.6 (a) before calcination; (b) after calcination 2.2 SEM 3,., F 1.6 U 1.6 S 1.6,., (6 nm), BET.,. F 4.8 U 1.6 S 1.6 ( 1 µm),.
No. 8 759. 3 / SEM Figure 3 SEM images of the samples prepared by varying initial molar ratios of formaldehyde to urea (a) F 1.6 U 1.6 S 1.6 powders before calcination; (b) F 4.8 U 1.6 S 1.6 powders before calcination; (c) F 4.8 U 1.6 S 1.6 monolith before calcination; (d) F 1.6 U 1.6 S 1.6 powders after calcination; (e) F 4.8 U 1.6 S 1.6 powders after calcination; (f) F 4.8 U 1.6 S 1.6 monolith after calcination F 1.6 U 1.6 S 1.6 F 4.8 U 1.6 S 1.6,. BET,. F 4.8 U 1.6 S 1.6 3c,,.. 2.3 FT-IR 4. 3100 3600 cm 1 N H O H, (Si OH) (CH 2 OH). 1100 cm 1 Si O Si [19], F 1.0 U 1.0 S 1.6, ( 1 ), 90%,,. 1295 cm 1 C N, [21]. 1520 750 cm 1 (CH 2 OH) [22,23],,,.,, 1 n( ) n( ) 2.0 4 Figure 4 IR spectra of the composite monoliths prepared by varying the molar ratio of formaldehyde to urea 2.4 DTA 5, 100. F 0.0 U 1.0 S 1.6, F.50 U 1.0 S 1.6 F 1.0 U 1.0 S 1.6 130 200,. 200 300 [18,19]. F 2.0 U 1.0 S 1.6, F 3.0 U 1.0 S 1.6, F 4.0 U 1.0 S 1.6,, 300,.,
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