Improved process for the preparation of spinnable solutions of polymers or copolymers of acrylonitrile with a high content of acrylonitrile, adapted to form of the spun yarns of a high degree of whiteness

摘要

Spinnable solutions of acrylonitrile polymers or copolymers having an acrylonitrile content higher than 85% by weight are prepared by polymerizing acrylonitrile, with or without an appropriate amount of one or more comonomers, in dimethylformamide in the presence of an organic peroxide catalyst and in the presence of from 0.02 to 0.04%, based on the weight of monomer(s), of thiourea dioxide (formamidine-sulphinic acid). Lauroyl peroxide is exemplified as catalyst and in examples the acrylonitrile is copolymerized with (a) sodium allyl sulphate and methyl methacrylate and (b) sodium allyl sulphate and ethyl acrylate, polymerization being terminated at incomplete conversion of monomers. Yarns having a good whiteness rating can be spun from the polymer solutions obtained.