Still other useful polymers are those of vinyl chloride, vinylidene chloride, methacrylonitrile and hydrocarbon olefins and copolymers of such monomers and of acrylonitrile with each other or with other monomers such as butadiene, isobutylene and an acrylate, such as ethyl acrylate, and methacrylate esters in which the latter monomers are present in minor amounts.