Improvement in mechanical properties of poly(p-phenylene sulfide) fibers by high-tension multiannealing method

High-tension multiannealing (HTMA) was applied to improve the tensile properties of poly(p-phenylene sulfide) fibers, which was furthermore applied to the fibers produced and improved with the zone-drawing and zone-annealing treatments. The HTMA treatment was repeatedly applied to the fibers under the conditions of a 250 degrees C temperature and an applied tension of between 201.0 and 188.0 MPa. As a result, at the 13th treatment the degree of crystallinity increased to 40%. On the other hand, the orientation factor of crystallites increased dramatically to 0.982 during the zone-drawing treatment, but increased only slightly during the subsequent treatments of zone annealing and HTMA. The finally obtained fiber had a tensile modulus of 10.4 GPa and a tensile strength of 0.73 GPa. (C) 2000 John Wiley & Sons, Inc.