CHEMBIO 3BM3 Lecture Notes - Lecture 8: Pi Bond, Polymerization
21 Apr 2019
School
Department
Course
Professor
Document Summary
Often have more polar functional groups: higher melting point in these cases. Condensation polymerizations: degree of polymerization (dp) grows slowly. Hard to get 100% dp, (like hard to get 100% on the exam) Chain growth polymerization (look back to radical chains: initiation. A reactive initiator molecule (ion, radical) is formed and reacts with a monomer to produce a new reactive species: propagation. The active species reacts with further monomers, which add to the end of the growing chain sequentially. Sigma bonds are stronger than pi bonds: breaking a pi bond creates a more stable bond (sigma)+heat. Mother nature doesn"t like radicals so the radicals will try to find other radicals to become more stable, when concentration is low: at high conc, radicals will be killed, termination. Polymerization continues to propagate until: a termination reaction converts the chain end to an inactive form or, monomer is completely consumed. Each step (initiation, propagation and termination) are all distinct, with different rate constants.
