Process for preparing copolymers comprising alpha -alkyl styrene and unsaturated nitrile

摘要

In the emulsion polymerization of an alpha -alkylstyrene and an unsaturated nitrile copolymerizable therewith in a weight proportion of 70:30 to 80:20 in the presence of a radical initiator, an improved process wherein the monomers are introduced into the reaction system in such a manner that the concentration of the unreacted unsaturated nitrile in the reaction system is not less than 31% by weight to the entire amount of the unreacted monomers in the reaction system at the completion of the introduction of the monomers, whereby a copolymer of the alpha -alkylstyrene and the unsaturated nitrile having an excellent thermal resistance is produced with marked decrease in the amount of unreacted monomers.