THE MECHANICAL-PROPERTIES OF TERNARY LIQUID-CRYSTALLINE POLYMER BLENDS

The possibility of improving the compatibility of and the adhesion bet ween liquid-crystalline poly(oxybenzoate-co-oxynaphthoate) (Vectra) an d polycarbonate (PC) by adding a stable compatibilizer based upon the transesterification between liquid-crystalline poly(oxybenzoate-co-eth ylene terephthalate) (POB/PET) (60/40) and polycarbonate was investiga ted. The goal was to provide a physical interaction between the matrix polymer and the liquid-crystalline polymer through a third polymer th at contained similar chemical structural units to those in both polyme rs. It was found that at proper compositions the adhesion between Vect ra and PC was greatly improved by the presence of the compatibilizer, as indicated by the morphological evidence. These ternary liquid-cryst alline polymer blends displayed improved ultimate tensile stress (30% increase as compared to PC) and elongation at break (seven times as co mpared to binary blend) even under a nominal injection-moulding proces s. The impact property of the ternary liquid-crystalline polymer blend was also improved as compared to that of the binary liquid-crystallin e polymer blends. Copyright (C) 1996 Elsevier Science Ltd.