BLENDS OF A PPO-PS ALLOY WITH A LIQUID-CRYSTALLINE POLYMER

Blends of a PPO-PS alloy with a liquid crystalline polymer have been studied for their dynamic properties, rheology, mechanical properties, and morphology. This work is an extension of our previous work on PPO/LCP blends. The addition of the LCP to the PPO-PS alloy resulted in a marked reduction in the viscosity of the blends and increased processibility. The dynamic studies showed that the alloy is immiscible and incompatible with the LCP at all concentrations. The tensile properties of the blends showed a drastic increase with the increase in LCP concentration, thus indicating that the LCP acted as a reinforcing agent. The tensile strength, secant modulus, and impact strength of the PPO-PS/LCP blends were significantly higher than that of PPO/LCP blends. Morphology of the injection molded samples of the PPO-PS/LCP blends showed that the in situ formed fibrous LCP phase was preserved in the solidified form. A distinct skin-core morphology was also seen for the blends, particularly with low LCP concentrations. The improvement of the mechanical properties of the blends is attributed to these in situ fibers of LCP embedded in the PPO-PS matrix. The improvement in the properties of PPO-PS/LCP over PPO/LCP is also attributed to the addition of the PS which consolidates the matrix. (C) 1995 John Wiley and Sons, Inc.