BLENDS OF PHENOLPHTHALEIN POLY(ETHER ETHER SULFONE) WITH A THERMOTROPIC LIQUID-CRYSTALLINE COPOLYESTER

Blends of phenolphthalein poly(ether ether sulfone) (PES-C) with a the rmotropic liquid crystalline copolyester (LCP) were prepared. Miscibil ity, morphology, thermal behavior, and mechanical properties of the PE S-C/LCP blends with various compositions were studied by using differe ntial scanning calorimetry (DSC), wide-angle x-ray diffraction (WAXD), dynamic mechanical analysis (DMA), tensile tests, and scanning electr on microscopy (SEM). Both DSC and DMA studies showed that the blends h ave two glass transition temperatures (T-g) corresponding to those of the PES-C-and LCP-rich phases, respectively. PES-C and LCP are partial ly miscible, the T-g's varying with composition. Young's modulus incre ases slightly with increasing LCP content owing to the high modulus of LCP, whereas the tensile strength greatly decreases with increase of LCP content. The interfaces between PES-C and LCP are weakly bonded, w ith rather poor interaction. SEM observations revealed that the blends have a two-phase structure and that the adhesion between the phases i s poor.