HIGH-CONVERSION POLYMERIZATION - 1. THEORY APPLICATION TO METHYL METHACRYLATE.

Abstract

In the reported study, the concept of polymer entanglements has been applied in conjunction with classical free-radical kinetics to describe vinyl polymerizations carried to high conversion. A kinetic model has been developed on the assumption that two populations of radicals exist in a high-conversion polymerization system: those radicals whose chain lengths are long enough to become entangled with neighboring molecules and have, therefore, a restricted mobility; and those shorter radicals whose mobilities are not strongly affected by diffusional effects. The model contains only two parameters in addition to the kinetic rate constants required to describe low-conversion polymerizations. The model so developed has been tested against experimental data obtained from the literature on the bulk polymerization of methyl methacrylate. The agreement between predicted and experimental monomer conversions and mol. wt. averages is found to be satisfactory.