Improvements in or relating to the preparation of spinnable solutions of poly acrylonitrile or copolymers having a high acrylonitrile content

摘要

A spinnable solution of polyacrylonitrile or a copolymer having an acrylonitrile content higher than 85% by weight and a molecular weight of from 60,000 to 65,000 is produced by a process comprising direct preparation of the polymer or copolymer solution starting from a mass comprising acrylonitrile in dimethyl formamide, preferably in association with other monomers, e.g. methyl methacrylate and sodium allyl sulphonate, characterized by starting, at a temperature of from 60 DEG to 65 DEG C. the polymerization of a mass containing at least 50% monomer(s) and stopping said process when from 30 to 40% of said monomer(s) has been converted. Terpolymers of acrylonitrile, sodium allyl sulphonate and methyl methacrylate, ethyl acrylate or methyl acrylate are prepared in the examples, using lauroyl peroxide as catalyst and thiourea dioxide as modifier.