| 摘要 |
Polymers containing at least 60% by weight of polymerized acrylonitrile (calculated on the total weight of the polymers) are made by subjecting acrylonitrile, alone or with a copolymerizable ethylenically unsaturated compound, to free-radical initiated polymerization in an aqueous emulsion or solution which is a nonsolvent for polyacrylonitrile in the presence of at least one polymer containing sulphonic acid groups or salts thereof or acidic sulphuric acid ester groups or salts thereof, e.g. polyvinyl, polyallyl, polymethallyl and polyallyl methoxy sulphonic acids, polystyrene, polymethylstyrene, polyhydroxystyrene and polymethoxystyrene sulphonic acids, sulphonated polystyrene and rubber, acid sulphuric esters of polyvinyl alcohol and cellulose, polymers of the monomers obtained by reacting acrylic, methacrylic or crotonic acids or chlorides, with hydroxyalkyl or hydroxyaryl sulphonic acids, monomers obtained by reacting the aforesaid acid chlorides with aminoalkyl sulphonic acids, e.g. taurine, addition products of acrolein and methacrolein polymers with bisulphites and copolymers of sulpho-group containing monomers with monomers such as styrene, acrylic and methacrylic esters, acrylonitrile and vinyl and vinylidene chlorides. Monomers which may be copolymerized with the acrylonitrile are acrylic and methacrylic esters, styrene, vinyl and vinylidene chlorides and vinyl acetate. Freeradical catalysts specified are hydrogen peroxide, persulphates, azo catalysts and redox systems, e.g. a persulphate-pyrosulphite combination. The polymerization medium preferably has an acid pH value. The products are soluble in solvents such as dimethyl formamide and from such solutions may be prepared films and filaments possessing resistance to discolouring influences, and good dyeability. Specification 807,241 is referred to. |
