ABSTRACT
A mixture of acrylonitrile and butyl acrylate was polymerized starting from a concentrated emulsion in water. The polymerization was initiated at room temperature by a redox system, consisting of reductants dissolved in the water phase and an oxidant dissolved in the dispersed phase. The initial polymerization was carried out adiabatically with self-heating until a temperature of about 70°C was reached; this was followed by additional heating in a water bath at a higher temperature, for a total polymerization time up to 30 min. The conversion thus achieved was higher than that obtained via the adiabatic process alone. An optimum temperature during the additional heating was observed. Because of the gel effect, the molecular weight of the 307product increased with time and the reaction rate became affected by diffusion. The additional heating enhanced the mobility of the species in the system, thus ensuring a final product with a composition near that of the feed.
