Kinetics of the free-radical copolymerization of isobornyl methacrylate and diethylene glycol dimethacrylate in the entire composition range

Abstract

The aim of the present study is to provide a quantitative description of the significant changes observed in the rate of a free-radical crosslinking polymerization when varying the crosslinker concentration from 0 to 100%. The kinetics of the free-radical copolymerization of isobornyl methacrylate and diethylene glycol dimethacrylate, in the entire composition range, was determined by differential scanning calorimetry at 80°C, using benzoyl peroxide as initiator. A simple kinetic model describing initiation, propagation, and termination steps by relevant mechanisms was used to fit the experimental curves of rate of polymerization vs. time up to conversions close to the maximum in the polymerization rate. In this range, the initiator efficiency could be considered constant and radical trapping negligible, a fact that enabled to keep a minimum number of adjustable parameters. The simple kinetic model provided an explanation of the significant changes observed in the polymerization rate when changing the blend composition. POLYM. ENG. SCI. 46:1641–1648, 2006. © 2006 Society of Plastics Engineers.