Ionization–liquid‐crystalline polymer synergistically reinforced poly(ethylene terephthalate) due to interfacial compatibilization by ion–dipole interactions

Abstract

AbstractTo enhance the compatibility of poly(ethylene terephthalate) (PET)/liquid crystalline polymer (LCP) composite, thereby mechanically strengthening the PET matrix, an optimally compatibilized composite of chain‐extended and ‐carboxylated PET ionomer and poly(4‐hydroxybenzoic acid–ran–6‐hydroxy‐2‐naphthoic acid) (HBA–HNA) was successfully prepared. Upon PET carboxylated chain extension with pyromellitic dianhydride and subsequent ionization with Zn(OH)2, the compatibility of the composite was distinctly improved, as verified by the refined dispersed‐phase morphology, increased number of refined HBA–HNA fibrils, reduced crystallinity, and improved complex viscosity. Compared with PET, the optimally compatibilized composite displayed a 70.1 and 148.7% increase in Young's modulus and tensile strength, respectively. Tentatively mechanistically, the interfacial interaction may change from weak hydrogen bonding to strong ion–dipole interactions due to the introduction of ionic groups, which remarkably boosts the interfacial compatibility, thereby achieving synergistic effects of the ionization and HBA–HNA inclusion to maximally strengthen PET. It seems that the synergistic ionization/LCP inclusion by a one‐pot method establishes a promising preparation approach to commercial PET engineering resins.