Miscibility and morphology of poly p-phenylene sulphide liquid crystal polymer blends

Blends of poly p-phenylene sulphide (PPS) and a liquid crystalline polymer (LCP) were made by two methods: (i) mixing and capillary extrusion (samples A), and (ii) injection moulding (samples B). To study miscibility in the m elt and solid states and the resulting morphology, techniques like polarize d light optical microscopy, capillary rheometry, dynamic mechanical thermal analysis and scanning electron microscopy with X-ray microanalysis were us ed. It was observed that the miscibility of the amorphous fractions of both polymers increased with increasing intensity (rates and stresses) of defor mational flow (shear and elongational). Samples A had a morphology composed of fibrils of both polymers, but a matrix made of only one polymer i.e. PP S. Samples B had a mainly fibrillar morphology, with no observable matrix, made of both polymers. Formation of pure LCP fibrils was not observed neith er in the extruded blends nor in the injection moulded samples. The additio n of LCP to PPS improved its mechanical properties. At a molecular level, t hese blends can be considered to be "molecular composites". (C) 1999 Kluwer Academic Publishers.