THE EFFECTS OF TEMPERATURE AND LIQUID-CRYSTALLINE POLYMER (LCP) ON MECHANICAL-PROPERTIES OF A BLEND OF POLYPHENYLENE SULFIDE AND LCP

The mechanical properties of polyphenylene sulphide (PPS) and liquid c rystalline polymer (LCP) blends were investigated over a range of temp eratures. The effect of blend composition on the brittle-ductile trans ition temperature (B-D) was also studied by differential scanning calo rimetry and scanning electron microscopy. Blends of various compositio ns (PPS/LCP; 90/10, 75/25, 50/50 and 25/75) were prepared and injectio n moulded. The bending test temperature was varied between -40 and 150 degrees C. The results showed a rapid load drop at the B-D transition region. The B-D transition temperature occurred in unannealed pure PP S, 90/10, 25/75 and 50/50 blends around 75 degrees C whilst in the ann ealed sample it was observed around 100 degrees C. In pure LCP and 25/ 75, no transition occurred. Partial miscibility of PPS and LCP was con firmed by SEM observations, bending modulus and thermal properties. Th e use of LCP, as a good reinforcing agent which can improve processabi lity and modulus, is discussed.