| 摘要 |
Acrylonitrile-vinyl alcohol copolymers are prepared by copolymerizing acrylonitrile with a vinyl trihaloacetate and subjecting the resulting copolymer to hydrolysis with a nitrogen base of pKb between 2.5 and 8. The copolymer may be dissolved in an organic solvent and extruded into a coagulating bath to form a fibre or cast into a film prior to hydrolysis. Specified trihaloacetates are vinyl trifluoro-, chlorodifluoro-, fluorodichloro-, trichloro-, bromodifluoro, and bromodichloro acetates. Specified bases are ammonium hydroxide, methanolic ammonia, methylamine, ethylamine, propylamine, butylamine, piperidine, dimethylamine, diethylamine, dipropylamine, dibutylamine, methylethylamine, trimethylamine, triethylamine and tributylamine. Specified solvents are N,N-dialkyl amides and dimethyl sulphoxide. Examples describe the copolymerization of acrylonitrile with (I, II and IV) vinyl trifluoroacetate, and (III) vinyl chlorodifluoroacetate, in the presence of azodiisobutyronitrile and solvents such as cyclohexane and heptane, and the hydrolysis of the products in the presence of (I-IV) aqueous ammonium hydroxide, and (II) aqueous piperidine and aqueous triethylamine. |
