Kinetic investigations of the free radical crosslinking copolymerization in the pre‐gel state, 2. Styrene/ethylene dimethacrylate and styrene/diisopropenylbenzene systems

A kinetic investigation of the free radical crosslinking copolymerization was carried out using the following monomer systems: styrene/ethylene dimethacrylate, styrene/m‐diisopropenyl‐benzene and styrene/p‐diisopropenylbenzene. The conversion curves of each individual monomer and the instantaneous composition of the copolymer formed were determined from vapor phase chromatography measurements. The rate of consumption of each monomer follows first order kinetics except for the system styrene/p‐diisopropenylbenzene in which strong deviations can be observed. The reactivity ratio of styrene, determined by VPC, is compared with the value obtained by the Kelen‐Tüdős linearization method. As for the system styrene/divinylbenzene, the fundamental role of the pendant bonds in the process has been established. Their ability to react with incoming radicals to form crosslinks determines the formation of interchain linkages and thus the gelation of the system.