The Mechanism of Copolymerization

Abstract

The mechanism of catalytic copolymerization of two monomers A and B is treated with the the aid of steady state approximation. Two initiation and two termination rates are assumed, one for each monomer. Four propagation rates are considered, corresponding to the four possibilities of addition, namely, addition of monomer A to a chain ending in A* or to a chain ending in B* and addition of monomer B to a chain ending in A* or to a chain ending in B*. Over-all rate and number average molecular weight are calculated. The composition of the polymer and the number distribution curves of groups of submolecules a and of submolecules b are calculated as functions of the monomer composition and two rate constant ratios. These last results are of general character and independent of the nature of the initiation and termination processes provided that the average degree of polymerization is ``high.''