GB764297A - Improvements in the polymerisation of acrylonitrile - Google Patents

Abstract

Graft polymers are prepared by heating to a temperature of between 25 DEG and 75 DEG C. in the presence of a polymerization catalyst a solution or dispersion of a monomer falling within one of the following general formul <FORM:0764297/IV(a)/1> (acrylamides) <FORM:0764297/IV(a)/2> (acrylates) <FORM:0764297/IV(a)/3> (itaconamides) <FORM:0764297/IV(a)/4> (citraconamides) <FORM:0764297/IV(a)/5> (vinyl esters) wherein R and R1 each represents a hydrogen atom or an alkyl group containing from 1 to 4 carbon atoms, R2 represents a hydrogen atom or a methyl group, R3 represents an alkyl group containing from 1 to 4 carbon atoms, R4 represents a hydrogen atom, a methyl group, an acylamino group wherein the acyl group is that of a saturated aliphatic carboxylic acid containing from 2 to 4 carbon atoms, or a carbalkoxylamino group wherein the alkoxyl group contains from 1 to 4 carbon atoms, R5, R6, R7, and R8 each represents a hydrogen atom, a methyl group, or an ethyl group, and R9 represents a hydrogen atom or an alkyl group containing from 1 to 3 carbon atoms, until the monomer has homopolymerized, then, without separating the homopolymer from its polymerization medium, adding 5 to 95 per cent of acrylonitrile, based on combined weight of acrylonitrile and other monomer, and continuing polymerization by heating the reaction mixture to a temperature between 25 DEG and 75 DEG C. until the acrylonitrile has been polymerized. Numerous monomers of the above general formul are specified, those employed in the examples being vinylacetate, N - methylacrylamide, N - methylmethacrylamide, N - isopropylmethacrylamide, methyl acrylate, methyl methacrylate, methyl acetaminoacrylate, methyl carbethoxyaminoacrylate, itaconamide, and citraconamide. Catalysts specified are benzoyl, acetyl benzoyl, lauryl, oleoyl, triacetone, urea and hydrogen peroxides, tert.-butyl hydroperoxide, alkyl percarbonates, sodium and potassium perborates, alkali metal and ammonium persulphates, ketazines, and azines; if desired a reducing agent such as an alkali metal bisulphite may also be present. Also present may be chain regulators such as hexyl, octyl, lauryl, dodecyl, and myristyl mercaptans. Polymerization may be carried out in aqueous medium, if desired with the aid of emulsifiers such as sodium lauryl sulphate, sodium isobutyl naphthalenesulphonate, sodium 7 - ethyl - 2 - methylundecan - 4 - sulphonate, alkali metal or amine addition salts of sulpho-succinic acid esters, alkali metal soaps, sulphonated fatty acid amides, alkali metal salts of alkane sulphonic acids, and sulphonated ethers; alternatively polymerisation is effected in solution in solvents such as acetone, aqueous acetone, acetonitrile, benzene, toluene, n-heptane, and aliphatic ethers. The resulting graft polymers, either alone or blended with polyacrylonitrile, may be formed into dyeable films and fibres from solution in solvents such as dimethyl formamide, dimethyl acetamide, dimethyl methoxyacetamide, dimethyl cyanamide, dimethyl cyanoacetamide, dimethylbeta-cyanopropionamide, ethylene carbonate, ethylene carbamate, gamma-butyrolactone, N-methyl-2-pyrrolidone, glycolonitrile, malononitrile, ethylene cyanohydrin, N-formyl morpholine, N-formyl pyrrolidine, dimethyl sulphone, dimethyl sulphoxide, tetramethylene sulphone, tetramethylene sulphoxide, and tetramethylmethanephosphonamide. Specifications 358,534, [Group IV], and 715,194 are referred to.