GB751926A - Improvements in the production of copolymers - Google Patents

Abstract

Terpolymers are made by copolymerizing a mixture of which each 100 parts contains (1) 70 to 95 parts of acrylonitrile; (2) 3 to 15 parts of an ethylenically unsaturated amide such as acrylamide and methacrylamide and their mono-N-alkyl derivatives, acrylic acid anilide and monoethyl anilide, and the corresponding amides of crotonic, maleic and fumaric acids; and (3) an ethylenically unsaturated ketone such as vinyl methyl ketone, vinyl phenyl ketone, and methyl isopropenyl ketone. Polymerization may be carried out batchwise or continuously, preferably in an aqueous medium having a weakly basic reaction, e.g. pH 7.5-8.5, and in the presence of a catalyst such as a mixture of sodium bisulphite, triethanolamine and potassium persulphate, or azo-isobutyronitrile; polymerization may be terminated by the addition of an excess of sodium bisulphite. All three monomers may be present at the beginning of the reaction, or one or two monomers may be present and the remainder added subsequently; during polymerization monomers may be added at the rate at which they polymerize. The terpolymers are soluble in dimethyl formamide and from such solutions may be produced fibres which are dyeable with acid, vat, acetate, and basic dyestuffs.