CLAS Chem 109C Chapter 27 Answer Key – – 1. What are the 2 major classes of synthetic polymers? 1) made by addition reactions using alkenes, conjugated dienes or epoxides as monomers Chain growth to make alkanes, polyalkenes or polyethers respectively these chains are built form one end to the other – 2) Step growth made by condensation reactions to make polyamides, polyesters or polyurethanes these – chains are built in random directions 2. What are the 3 subclasses (or mechanisms) of chain-growth polymers? 1) anionic 2) cationic 3) radical 3. Describe the 3 phases of chain-growth polymerization. Initiation, propagation and termination 4. What is an ideal initiator monomer for each of the 3 subclasses of chain-growth polymerization? and super strong base initiators (ex RLi) and monomers with electron withdrawing groups 1) anionic 2) cationic strong Lewis acid initiators (ex BF3) and monomers with electron donating groups 3) radical peroxide (R-O-O-R) or azo (R-N=N-R) initiators and monomers that can have resonance or hyperconjugation with the radical 5. Draw a short segment of polymer that would form from the following monomers: a. styrene b. methyl methacrylate c. 2-ethyloxirane a. n b. n 5. What monomer would you use to synthesize the following polymers? a. b. n c.
CLAS – Chem 109C – Chapter 27 Answer Key 1. What are the 2 major classes of synthetic polymers? 1) Chain growth made by addition reactions using alkenes, conjugated dienes or epoxides as monomers to make alkanes, polyalkenes or polyethers respectively – these chains are built form one end to the other 2) Step growth made by condensation reactions to make polyamides, polyesters or polyurethanes – these chains are built in random directions 2. What are the 3 subclasses (or mechanisms) of chain-growth polymers? 1) anionic 2) cationic 3) radical 3. Describe the 3 phases of chain-growth polymerization. Initiation, propagation and termination 4. What is an ideal initiator and monomer for each of the 3 subclasses of chain-growth polymerization? 1) anionic super strong base initiators (ex RLi) and monomers with electron withdrawing groups 2) cationic strong Lewis acid initiators (ex BF3) and monomers with electron donating groups 3) radical peroxide (R-O-O-R) or azo (R-N=N-R) initiators and monomers that can have resonance or hyperconjugation with the radical 5. Draw a short segment of polymer that would form from the following monomers: a. styrene b. methyl methacrylate c. 2-ethyloxirane a. n b. n 5. What monomer would you use to synthesize the following polymers? a. b. n c.
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