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

Blends of thermotropic liquid crystalline polymer (TLCP) with poly(butylene terephthale) (PBT) were prepared by coprecipitation from a common solvent. The blends (5%, 10%, and 20% LCP/PBT) were processed for fiber spinning to examine tensile properties in various draw ratios. To find optimized processing conditions, such as retention time and temperature in capillary rheometer, thermal treatment of the fibers was carried out in DSC at 250 degrees C and 290 degrees C, respectively. There were no significant chemical changes at 250 degrees C. The fibers were extruded through a capillary die at 245 degrees C to produce a monofilament. In all blends, LCP domains in PBT matrix were very well dispersed and showed fine spherical particles. The values of ultimate strength were maximum at the 5 wt% level of LCP in the blends, and then decreased when LCP content was increased up to 20%. lnitial modulus monotonically increased with LCP content in all cases.