THE ROLE OF PARTIAL MISCIBILITY ON THE PROPERTIES OF TERNARY BLENDS OF LIQUID-CRYSTALLINE COPOLYESTERS AND POLYETHERIMIDE

Binary blends of liquid crystalline copoly(oxybenzoate-p-ethylene tere phthalate) at molar ratio 60/40, POB-PET, and polyetherimide (PEI) wer e investigated with differential scanning calorimetry and polarised op tical microscopy. It was found that POB-PET and PEI were partially mis cible when PEI was the major component. Adding a small amount (5 phr) of POB-PET to the originally immiscible blends of liquid crystalline c opoly(oxybenzoate-naphthalate) (73/27), Vectra, and PEI resulted in be tter interfacial adhesions between Vectra and PEI as evidenced by the morphological observations with scanning electron microscopy. The enha ncement in the interfacial adhesions caused an increase in the ultimat e tensile strength and the impact strength of these ternary blends of Vectra, POB-PET and PEI as compared to that of the corresponding binar y blends of Vectra and PEI in an injection molding process. (C) 1998 E lsevier Science Ltd. All rights reserved.