POLY(PHENYLENE SULFIDE) THERMOTROPIC LIQUID-CRYSTALLINE POLYMER BLENDS - A COMPARATIVE-STUDY OF THERMAL-PROPERTIES, PHASE-BEHAVIOR AND MORPHOLOGY OF BLENDS GENERATED BY DIFFERENT TECHNIQUES

Blends of poly(phenylene sulphide) and poly(ethylene terephthalate-co- oxybenzoate), an aliphatic-aromatic thermotropic liquid crystalline po lymer (TLCP), were prepared by different blending techniques and their thermal properties, phase behaviour and morphology were compared usin g differential scanning calorimetry (d.s.c.), polarized light optical microscopy (p.l.o.m.) and scanning electron microscopy (s.e.m.). Melti ng transitions and phase behaviour of the blends were dependent on the preparation method. While blends prepared by the precipitation method appeared monophasic, those prepared by melt-mixing were seen to be ph ase separated. The melt-mixed blends show macrophase-separated morphol ogy indicating poor phase mixing whereas the co-precipitated blends of the same composition exhibit a disperse-type morphology, as observed by p.l.o.m. In comparison to melt-mixed blends, co-precipitated blends were seen to be uniform and continuous. (C) 1998 Elsevier Science Ltd . All rights reserved.