COMPATIBILIZING EFFECT OF A THERMOTROPIC LIQUID-CRYSTALLINE COMPATIBILIZER ON LIQUID-CRYSTALLINE POLYCARBONATE POLY(P-PHENYLENE OXIDE) BLENDS

The compatibilizing effect of a thermotropic block-graft copolymer (LC BG) as a compatibilizer on thermotropic liquid-crystalline (LC) polyca rbonate (LCPC)/poly(p-phenylene oxide) (PPO) blends was studied. Compa tibility, morphology and mechanical properties of the blend systems we re investigated by differential scanning calorimetry (DSC), thermal me chanical analysis (TMA) and scanning electron microscopy (SEM). The bl end without the compatibilizer formed thermotropic LC phases, based on LCPC domains, and had a phase-separated structure. The LC temperature ranges of the blends with LCBG were wider than that of the blend with out the compatibilizer. DSC, SEM and TMA data showed that in the blend s containing the compatibilizer the compatibility and the viscoelastic ity were improved, because LCBG segments penetrate into both the PPO m atrices and the LCPC domains in the blends. These results suggest that LCBG acts as a good compatibilizer for blends.