Commercial Polymers. AK_Spiess Basis Seminar. Chulsoon Moon

Transcription

1 Commercial Polymers AK_Spiess Basis Seminar Chulsoon Moon

2 Outline Classification of polymers Natural vs. synthetic Addition vs. Condensation Thermoplastic vs. Thermosetting Commercial polymers the most commonly used polymers in ordinary life (poymerization, property, application) NMR in polymer analysis Composition (copolymers, polymer/additives) Mircro-structure (branching, tacticity, enchainment, sequence distribution ) Molecular weight (End-group analysis)

3 Classification of Polymers Natural polymers: plants, animal, and people.. (starch, cellulose, proteins, silk, and natural rubber ) Synthetic polymers: plastics, commercial polymers.. (styrene-butadiene rubber, nylon, PE, PP, PVC, ABS, SAN, PMMA..)

4 Polymerization mechanisms Condensation polymers (step growth polymers) + O C C O O 2 2 O C O C O O C 2 C 2 O C (Polyester, polycarbonate, polyamide, polyurethane..) O C O PET C 2 C 2 Addition polymers (chain growth polymers) C R C z C R C C 2 =CR Z repeating z R R C C C C C R C n Z: an initiating species (a radical, cation, anion) (Polymers from alkenes or functionalized alkenes..)

5 Thermal properties Thermoplastic polymers: soften reversibly when heated Molded and remolded easily Addition polymers (ABS, PP, PVC, ABS, PET ) Thermosetting polymers: harden permanently when heated Cross-linking hinder bending and rotations (harder, more brittle) Epoxy resins, phenol resins..

6 PET(Poly ethylene terephthalate) + trans-esterification of ethylene gylcol + terephthalic acid condensation & thermoplastic polymer Good transparency, strength, and gas barrier property widely used for soft drink bottle Recycling is more practical

7 PE(Poly ethylene) C C ethene n Polyethylene (DPE, LDPE) The simplest and the most popular polymer in the world Grocery bag, shampoo bottles, electrical insulation, children s toys Depending on polymerization processes: LDPE(Low-Density PE :more branching :soft) DPE(igh-Density PE :high crystallinity :rigid)

8 PE(Microstructure_branching) Backbiting Mechanism C24 C 3 C 2 C C 3 Six-membered transition state C4 branch C 2 C C2,C6 branch Multi-intramolecular transfer

9 PE(Microstructure_branching) 13 C-1D in TCE-d 2 at 100 Branch contents C1 C2 C4 C5 C 6 Ethylene main chain Monomer contensts (mole ratio) propene butene hexene heptene octene Ethylene: 1000 mole C4 C5 C6 C5 C1 C6 C1 C5 C4 C6 C1 C ppm

10 PE(End-group analysis: PE_O) O 1 2 n 3 C 3 2O DMSO PE main chain 3 1-1D NMR Average Chain number~17 (mw~536) ppm

11 PP (Poly Propylene) C propene C C 3 Crystallinity: between LDPE and DPE Automotive industry, yogurt container, textiles, stationery n C 3 Polypropylene (PP) Structure and property: tacticity

12 Tacticity Is stereochemistry in polymers Is generally applies to addition polymers with one-hydrogen substituent as to do with which side of the chain the R group is placed. isotactic syndiotactic atactic as many things with structure and physical properties (rigidity, crystallinity, solubility, melting point..) Can be measured by 1 and 13 C-NMR

13 Tacticity(PP) β-c 2 13 C-1D in TCE-d2 at β α n C 3 C 3 C 3 Isotactic (mm) Methyl C 3 C 3 mm syndiotactic(rr) C 3 mr rr C 3 C 3 heterotactic (mr) C ppm

14 PS (Poly Styrene) C C 2 n styrene Polystyrene (PS) Expanded PS, Extruded PS (Styrofoam) thermal insulation, molded objects as tableware (forks, knives, and spoons) Not easily recyclable (takes so long time to decompose) Co-polymer (SAN, SBR, ABS..)

15 PS_Tacticity n crystals amorphous

16 Tacticity_sPS 13 C-1D in TCE-d2 at Isoatactic Syn- Syn- Iso- Ph Ph Ph Ph Ph Ph Ph Ph Ph Ph Ph Ph ppm atactic Ph Ph Ph Ph Ph Ph C 2 C ppm

17 Composition(SBR) 1-1D in CDCl C-1D in CDCl ppm Ratio of Styrene :1,2-BD(Vinyl):1,4-BD by 1-NMR Styrene Vinyl (-C=) 1,4-BD (-C=) Vinyl (=C 2 ) ppm C 2 - Ratio of Cis,Trans Bd by 13C-NMR trans cis

18 PVC (Poly Vinyl Chloride) C C Cl Cl Vinyl chloride 2/3 : manufacture of pipe, construction Cheap, durable, easy to assemble Rigid and somewhat brittle Phthalate plasticizer (upvc:unplasticizer PVC) Monomer :Carcinogenic nature, Dioxin(as a by-product) n Polyvinyl chloride (PVC)

19 Composition (PVC/DOP) 1-1D in TCE-d 2 at 100 O Et O O Et O Di-n-octyl phthalate(dop) PVC(-CCl-) DOP(-OC 2 -) n DOP (Aromatics) solvent PVC Cl ppm PVC : DOP = ( ) : 4/4 26 : 1 (mole ratio)

20 Polymer additives Additives: Many plastics are virtually useless alone Fillers - to enhance properties such as wear/strength/toughness/durability of plastics.talc and clay may be used to bulk out the plastic reducing costs Plasticizers - to make the plastic less hard or brittle Stabilisers: to prevent degradation due to moisture or UV light Lubricants: to make the polymer easier to form and self lubricating in use (sulphides and waxes) Flame retardants: to prevent combustion in materials such as domestic foams Blowing agents: to permit foams to be blown Anti-static agents: to prevent the build up of electrical charge.

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22 Thank you!!