Synthesis and characterization of thermotropic liquid crystalline polyester/multi-walled carbon nanotube nanocomposites

Abstract

A thermotropic liquid crystalline polymer (TLCP) was synthesized from 4,4'-Oxobisbenzoic acid and methylhydroquinone by low-temperature solution polycondensation. Nanocomposites of TLCP with the content of MWNTs from 0 wt% to 10 wt% were prepared by in situ polymerization. Scanning electron microscopy images showed that the MWNTs were well-separated in the TLCP matrix. Differential scanning calorimetry, thermogravimetric analyzer, X-ray diffraction, and polarized optical microscopy were used to investigate the thermal behavior, crystalline structure and liquid crystalline properties of the pure TLCP and TLCP/MWNT nanocomposites. The thermogravimetric analyses indicated that a small amount of MWNTs could improve the thermal stability of TLCP matrix. Furthermore, the result of differential scanning calorimetry demonstrated that both melt transition temperatures and isotropic transition temperatures of the hybrids were enhanced. Our study provided a design guide for CNT-filled TLCP composites which could be favorable for industrial use.