BLENDS OF THERMOTROPIC LIQUID-CRYSTALLINE POLYMER WITH A FLEXIBLE SIDE-GROUP AND POLY(BUTYLENE TEREPHTHALATE)

Blends of thermotropic liquid crystalline polymer (TLCP) with poly(but ylene terephthale) (PBT) were prepared by coprecipitation from a commo n solvent. The blends (5%, 10%, and 20% LCP/PBT) were processed for fi ber spinning to examine tensile properties in various draw ratios. To find optimized processing conditions, such as retention time and tempe rature in capillary rheometer, thermal treatment of the fibers was car ried out in DSC at 250 degrees C and 290 degrees C, respectively. Ther e were no significant chemical changes at 250 degrees C. The fibers we re extruded through a capillary die at 245 degrees C to produce a mono filament. In all blends, LCP domains in PBT matrix were very well disp ersed and showed fine spherical particles. The values of ultimate stre ngth were maximum at the 5 wt% level of LCP in the blends, and then de creased when LCP content was increased up to 20%. lnitial modulus mono tonically increased with LCP content in all cases.