Radical copolymerisation propagation kinetics of methyl ethacrylate and styrene

Pulsed-laser polymerisation has been used to investigate the radical copoly merisation kinetics of styrene with methyl ethacrylate. Experiments were co nducted over the temperature range 30-80 degreesC. The results for copolyme r composition and the average propagation rate coefficients, [k(p)], can be interpreted using terminal model kinetics. It is argued that the primary f actor influencing the copolymerisation [k(p)] data is the sterically hinder ed methyl ethacrylate radicals and this steric effect swamps any enthalpic penultimate unit effect which may be expected to play a role in the copolym erisation reaction. The terminal model reactivity ratios are a strong funct ion of temperature and this reflects the importance of depropagation reacti ons at higher temperatures and lower concentrations of methyl ethacrylate. (C) 2000 Elsevier Science Ltd. All rights reserved.