摘要 |
Fibers with enhanced tenacity are prepared by heat treating oriented fibers from anisotropic-melt-forming linear aromatic and cycloaliphatic polymers, especially polyesters (including copolyesters), while said fibers are essentially relaxed, at temperatures near the flow temperature but sufficiently below to prevent substantial interfilament fusion, for a period of from five seconds to several hours until the fiber tenacity is increased by at least 50% and to at least 10 grams per denier.
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