Miscibility in blends of liquid crystalline poly(p-oxybenzoate-co-p-phenyleneisophthalate) and polyarylate

Abstract

The miscibility of liquid crystalline poly(p-oxybenzoate-co-p-phenyleneisophthalate) (HIQ35) and polyarylate (PAr) coprecipitated from a mixed solvent of phenol/tetrachloroethane was investigated with differential scanning calorimetry. It was found that the amorphous phase of HIQ35 and PAr formed a partially miscible blend at low concentration of HIQ35. No measurable interaction between HIQ35 and PAr occurred when the weight fraction of HIQ35 was close to or less than that of polyarylate, as evidenced by wide-angle X-ray diffraction results. Upon annealing at 315 degrees C for several minutes, the apparent miscibility of HIQ35 with polyarylate appeared as a result of an initial reaction between the polymers. For longer annealing time, the thermal degradation of HIQ35 joined in the reaction. This reaction or degradation in the blend was confirmed by nuclear magnetic resonance analysis and the intrinsic viscosity measurement of the blend. (C) 1998 John Wiley & Sons, Inc.