Improvements in processes for preparing polymers from acrylonitrile

摘要

A process for preparing acrylonitrile polymers comprises introducing continuously into a polymerization system a mixture comprising from 5 to 95 parts by weight of (1) acrylonitrile alone, or together with not more than 15 per cent, based on total weight of monomers, of at least one other different monoethylenically unsaturated monomer containing a -CH = C< group and from 95 to 5 parts of (2) a preformed polymer of a monomer or monomers represented by the following formul : wherein R and R1 each represents hydrogen or an alkyl group containing from 1 to 4 carbon atoms, R2 represents an alkyl group containing from 1 to 4 carbon atoms, R3 represents hydrogen or a methyl group and R4 represents an alkyl group containing from 1 to 3 carbon atoms, subjecting the mixture to polymerizing conditions until from 70 per cent to 100 per cent of the monomers have been converted to graft polymer and withdrawing reacted mixture from the system either continuously at about the same rate as the mixture of monomer and polymer is introduced into the system or after the continuous introduction. The polymers of the monomers of the above formul may be used either before or after they have been separated from their polymerization media and may be prepared by polymerizing them alone or together with other monomers of the above general formul , acrylonitrile or other monomers containing a -CH = C< group such as styrene, alpha-methyl styrene, p-acetamino-styrene, alpha-acetoxy styrene, ethyl and isopropyl vinyl ethers, methyl and ethyl vinyl and isopropenyl ketones, dimethyl, diethyl and diisopropyl maleates and fumarates, fumaronitrile, methacrylonitrile, acrylic and methacrylic acids, ethylene, isobutylene, vinyl and vinylidene chlorides, vinyl sulphonamide, N-vinyl phthalimide; 2-vinyl pyridine, 4-vinyl pyridine, 2-methyl-5-vinyl pyridine, and 2-vinyl-6-methyl pyridine. Polymerization may be carried out in solvents such as acetonitrile, benzene, toluene, n-heptane, aliphatic ethers, acetone and mixtures of acetone and water or, and preferably, in aqueous media which may contain emulsifiers such as sodium lauryl sulphate, sodium isobutyl naphthalene sulphonate, alkali metal or amine addition salts of sulphosuccinic esters, alkali metal salts of fatty acids, sulphonated fatty acid amides, alkali metal salts of alkane sulphonic acids, sulphonated ethers and aryloxy polyalkylene ether sulphonates; also present may be chain regulators such as hexyl, octyl, lauryl, dodecyl and myristyl mercaptans. Polymerization may be accelerated by heat, actinic light and catalysts such as benzoyl, acetyl, acetyl benzoyl, oleoyl, triacetone, urea and hydrogen peroxides, t-butyl hydroperoxide, alkyl percarbonates, sodium, potassium and ammonium persulphates and perborates, azines and ketazines, and catalyst activators such as alkali metal sulphites, bisulphites and metabisulphites. Specifications 764,296, 764,297, 764,298, 764,299, 764,300, 764,301, 781,434, 781,435 and 781,436 are referred to.