| 摘要 |
A process for preparing acrylonitrile polymer plexifilamentary strands comprises dispersing in water 25 to 45% by weight of an acrylic polymer containing at least 91% by weight acrylonitrile units and up to 9% by weight of one or more copolymeric units and having an intrinsic viscosity of 0.6 to 2.0, 7 to 23 mu eq./g. enolizable groups after mild acid treatment, 15 to 70 mu eq./g. thioether ends derived from a water insoluble mercaptan and less than 3 mu eq./g. oxidizable hydrolysis fragments, heating the dispersion to a temperature of 200 DEG to 300 DEG C. while maintaining the dispersion under sufficient pressure to maintain the water in the liquid state, the time of heating not exceeding about 30 minutes, and promptly flash-extruding the dispersion through an orifice into a region of substantially lower temperature and pressure to form a continuous strand of filbrillated plexifilaments.
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