Properties of thermotropic liquid crystalline polyester nanocomposites derived from multi-walled carbon nanotubes

A series of nanocomposites containing multi-walled carbon nanotubes (MWNTs) and terephthaloyl-di-p-oxybenzoyl chloride-triethylene glycol copolyester (T-T) were prepared by in-situ high-temperature solution polycondensation. The liquid crystalline properties and thermal stability of the resulted MWNTs/T-T nanocomposites were investigated by wide-angle X-ray diffraction (WAXD), polarized optical microscopy (POM), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TGA), respectively. The results showed that MWNT doping at a low concentration improved the thermal stability of T-T matrix and expanded the nematic temperature range without largely changing its conformation, making it more suitable for processing. The dispersion of MWNTs and interfacial interactions between the thermotropic liquid crystalline polymer (TLCP) molecules and the carbon nanotubes (CNTs) were investigated by scanning electron microscopy (SEM) and optical spectroscopies. The UV-vis spectroscopy and fluorescence spectra supported a strong pi-pi* interaction between the polymer and the nanotube.