| Abstract: | Chemical reactions leading to crosslinking were followed by rheometrical studies during curing at different temperatures and compositions of compatible species. The condensation reactions between two copolymers of styrene and maleic anhydride, and several α,ω-dihydroxyoligostyrenes, lead to an experimental variation of the elastic modulus (G′)t. A kinetic scheme is proposed, selecting the most reliable reactions, which describes the experimental behaviour adequately. According to this scheme, the rate constants of interpolymeric condensation reactions were evaluated. It appears that the values obtained for grafting and crosslinking are quite the same. They depend mainly, in absence of a catalyst, on the molecular weight of the oligomer and on the local viscosity, which is a function of composition. In presence of a catalyst, there is a large increase of the constant, indicating that the chemical step is dominating the diffusion process. |
