EFFECT OF CHAIN-LENGTH DEPENDENCE OF TERMINATION RATE-CONSTANT ON THE KINETICS OF FREE-RADICAL POLYMERIZATION .2. EVALUATION OF AN ANALYTICAL EXPRESSION FOR THE RATE OF POLYMERIZATION

The nonclassical kinetics of low-conversion, free-radical polymerization have been studied. The model adopted assumes a termination rate constant for radicals of size m and n given by kappa-t(n,m) = kappa-t0(nm)-a. When this chain-length dependency for the termination rate constant was used, a simple analytical expression for the rate of nonclassical free-radical polymerization, R(p), is found to be R(p) = (Constant)[M][I]0.5(X(n))a-eta-0.5, where [M] and [I] are monomer and initiator concentrations, X(n) is the number-average degree of polymerization, and eta is the viscosity of medium. This expression was compared and found to be in good agreement with experimental data obtained in the polymerization of several monomers.