Fiber property and structure development of polyester blend fibers reinforced with a thermotropic liquid-crystal polymer

Ternary blend fibers (TBFs), based on melt blends of poly(ethylene 2,6-naphthalate), poly(ethylene terephthalate), and a thermotropic liquid-crystal polymer (TLCP), were prepared by a process of melt blending and spinning to achieve high-performance fibers. The reinforcement effect of the polymer matrix by the TLCP component, the fibrillar structure with TLCP fibrils of high aspect ratios, and the development of more ordered and perfect crystalline structures by an annealing process resulted in the improvement of the tensile strength and modulus for the TBFs. An increase in the apparent crystallite size with the spinning speed was attributed to the development of larger crystallites and more ordered crystalline structures in the annealed TBFs. The birefringence and density of the TBFs increased with increasing spinning speed, the TBFs becoming more oriented and the crystal packing becoming more enhanced. The molecular orientation was an important factor in determining the tensile strength and modulus of the TBFs. (C) 2003 Wiley Periodicals, Inc.