HOCHORIENTIERTE KURZFASERN AUS AROMATISCHEN POLYAMIDEN.

摘要

High oriented poly(p-phenylenetetraphthalamide) short fibers having an inherent viscosity of at least 5.0 and a dimension of 2-12 mu m in diameter and 1000-5000 mu m in length are provided. Those fibers further have a physical form of irregular cross-sections and needle point-like ends similar to those of natural wood pulp fibers, a crystalline properties such as a crystallinity of more than 50%, an orientation angle of less than 25 DEG and an apparent crystallite size of more than 50 ANGSTROM as determined from an X-ray diffractogram scan, and a cross-section with four extinction positions through 360 DEG rotation when observed under a polarizing microscope. These fibers are prepared, without spinning steps, by subjecting the molecular chains of poly(p-phenyleneterephthalamide) to mechanical parallelization during the growth of the chains in a polymerization system therefor cotaining a pyridine/amide-based solvent.