Microflow system for controlled synthesis of ethylene-vinyl acetate copolymers: Continuous copolymerization and kinetic study

Ethylene content in ethylene–vinyl acetate copolymers (EVA) is a key factor that determines its further usage. While conventional batch reactor for EVA synthesis faces the problem of heterogeneous reaction environment and temperature control. A microflow system was designed to avoid these problems and facilitate the synthesis of EVA with controlled ethylene content. Continuous flow synthesis of EVA by solution free radical copolymerization was realized homogeneously based on this microflow system. 13 C NMR spectra indicate that EVA obtained in microflow system has less ethylene concentrated sequence than EVA obtained in batch reactor. By operating the microflow system in a stop-flow method, we developed a simple kinetic model of copolymerization and measured the reactivity ratios of ethylene and vinyl acetate copolymerization in tert -butyl alcohol and dimethyl carbonate. The microflow system is demonstrated to be a powerful tool in kinetic and mechanism study and engineering application of copolymerization processes involving monomers which are gas phase under conventional condition.