| 摘要 |
Solutions and gels of polyacrylonitrile and copolymers of acrylonitrile and another monomer containing in the copolymer molecule at least 85 per cent of acrylonitrile are made by dissolving or swelling the polymer or copolymer in a mixture comprising nitromethane and water. The nitromethane may be in part replaced by nitroethane, 1-nitropropane or 2-nitropropane and the solvent mixtures may include the solvents used in U.S.A. Specifications 2,404,714-2,404,727. The other monomer may be 2-vinyl pyridine, styrene, dimethylitaconate, methyl vinyl ketone, methacrylic acid, ethyl vinyl sulphone, methacrylonitrile, isobutylene, vinyl acetate, vinyl chloride or butadiene. In an example, polyacrylonitrile of M.W. 60,000 is made by slowly adding acrylonitrile to a heated mixture of water, ammonium persulphate and sodium bisulphite. The solutions or gels of the polymer or copolymer may be extruded into filaments or fibres by dry or wet spinning techniques, using coagulating baths containing water, glycerine, alcohol, ether or aqueous solutions of salts, alkalis or acids, or cast into films or tubes, or made into artificial horsehair, bristles, ribbons, covers for rayon spinning bobbins, liners, battery separators, protective clothing, carpeting, upholstery, tents, awnings, tarpaulins, flags and sails. The fibres may be hot or cold-drawn. Specifications 459,596 and 461,675 are referred to. |
