| 摘要 |
1,229,427. Methacrylonitrile polymer films and filaments. MITSUBISHI RAYON CO. Ltd. 25 March, 1968 [3 April, 1967], No. 14197/68. Heading B5B. [Also in Division C3] Films and fibres of an oriented crystalline polymer of methacrylonitrile having a monoclinic crystal structure with a=13À9A‹, b= 7À1A‹, c=7À6A‹ and #=97‹ 40' are obtained by stretching a film or fibre of the polymer and then subjecting the stretched film or fibre to heat treatment under tension at 120‹ to 180‹ C. The stretching is suitably carried out at 80‹ to 150‹ C. in the presence of a solvent or at 140‹ to 180‹ C. in the absence of a solvent. In examples: (1) methacrylonitrile polymer is mixed with dimethylformamide and the mixture is cast on a glass plate to form a film. After drying, the film is stretched between rollers heated at 90‹ C., and further stretched at 100‹ C. to twice its original length, which also frees it from remaining solvent. The film is then heat set at 140‹ C. at constant length. (2) Methacrylonitrile polymer is dissolved in trifluoroacetic acid, and the solution cast on a glass plate to form a film. Solvent is removed by extraction with boiling water, and the film stretched between rollers at 140‹ C., and then heat set at 160‹ C. while permitting 5% shrinkage. (3) Film made as in (2) is biaxially stretched at 160‹ C. to 3: 1 longitudinally and to 2:1 transversely and is then heat-set at 160‹ C. under tension. (4) Methacrylonitrile polymer is dissolved in trifluoroacetic acid and the solution is dry-spun into an atmosphere heated to 80‹ C. to form filaments, which are stretched to 5:1 by the use of a heated roller at 140‹ C. freed from solvent and then heat-set at constant length at 180‹ C. (5) A spinning solution made by dissolving methacrylonitrile polymer in 70% nitric acid is wet-spun into a coagulating bath of 55% aqueous nitric acid to form filaments, which are washed with boiling water and stretched to 5:1 in ethylene glycol at 140‹ C. The stretched fibres are then heat-set at 160‹ C. (6) A methacrylonitrile-vinyl pyridine copolymer is dry spun as in (4), stretched to 8:1 on a heated plate at 140‹ C. and heat set at 170‹ C. while permitting 10% shrinkage. (7) A dry-spinning solution as in (4) is dry-spun using a column having a temperature of 100‹ C. at the top and 70‹ C. at the bottom. The filaments were washed with methanol and dried, and stretched to 7:1 at 160‹ C., followed by heat-setting at constant length at 180‹ C.
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