GB764298A - Improvements in the polymerisation of acrylonitrile - Google Patents

Abstract

Graft polymers are prepared by polymerizing acrylonitrile as the sole monomeric material in the presence of a preformed interpolymer of monomers containing ethenoid unsaturation which has not been separated from its polymerization medium before the addition of acrylonitrile. Preferred monomers from which the interpolymers are formed are acrylamide and methacrylamide and their N-methyl, -ethyl, -n-propyl, -isopropyl, -n-butyl and -isobutyl substitution products, the methyl, ethyl, n-propyl and isopropyl esters of acrylic, methacrylic, acylaminoacrylic and carbalkoxyaminoacrylic acids, itaconamide and citraconamide and their N-methyl or -ethyl substitution products, vinyl acetate, propionate and butyrates, isopropenyl acetate, styrene, alpha-methylstyrene, para-acetaminostyrene, alpha-acetoxystyrene, ethylene, vinyl and vinylidene chlorides, ethyl and isopropyl vinyl ethers, methyl and ethy isopropenyl ketones, methyl and ethyl vinyl ketones, dimethyl, diethyl and diisopropyl maleates and fumarates, acrylic and methacrylic acids, fumaronitrile, acrylonitrile, methacrylonitrile, N-vinylphthalimide, and butadiene. Polymerization may be carried out in an aqueous medium or in solution in a solvent such as acetonitrile or aqueous acetone in the presence of catalysts such as organic peroxides, e.g. benzoyl, acetyl, acetyl benzoyl, lauryl, oleoyl, triacetone and urea peroxides, tert.-butyl hydroperoxide, alkyl percarbonates, sodium and potassium perborates, alkali metal and ammonium persulphates, ketazines and azines; the oxidizing catalysts may be used together with reducing agents such as potassium and sodium bisulphites. Aqueous media may contain emulsifiers such as sodium lauryl sulphate, sodium isobutyl naphthalene sulphonate, sodium 7-ethyl-2-methylundecan-4-sulphonate, sulphonated ethers, alkali metal or amine addition salts of sulphosuccinic acid esters, alkali metal salts of fatty acids containing from 12 to 20 carbon atoms, sulphonated fatty acid amides and sulphonated esters. Polymerization may also be carried out in the presence of hexyl, octyl, lauryl, dodecyl, and myristyl mercaptans as chain regulators. The graft polymers produced may be used in the preparation of dyeable fibres from solution in dimethyl formamide, either alone or in admixture with polyacrylonitrile. Specifications 358,534, [Group IV], 690,937 and 764,297 are referred to.