THE THERMAL AND MECHANICAL-BEHAVIOR OF POLY(ETHYLENE-TEREPHTHALATE) FIBERS INCORPORATING NOVEL THERMOTROPIC LIQUID-CRYSTALLINE COPOLYMERS

This investigation explores the potential of improving the performance of poly(ethylene terephthalate) fibers by incorporating novel thermot ropic liquid crystalline copolymers. Fibers were obtained by melt extr usion and the effect of processing conditions, i.e., spinning temperat ure, stretch ratio, and post treatment evaluated. The fibers were test ed for mechanical performance, dimensional instability (shrinkage), an d the development of shrinkage stresses. A segmented block copolymer c onsisting of rigid-rod, diad, and flexible coil segments was found to improve the performance of poly (ethylene terephthalate) (PET) fibers. At a concentration of 20 wt%, the alternating block copolymer increas ed the tensile modulus of the fibers by 40% and decreased free shrinka ge by 20% compared to neat PET. (C) 1994 John Wiley & Sons, Inc.