Preparation And Characterization Of Thermotropic Liquid Crystal/carbon Nanotube Composites

Due to their unique structure, excellent mechanical and photo-electronic properties, carbon nanotubes (CNTs) have been envisioned as promising fillers for nanocomposites. And so many researchers have done much work on the preparation and the study of the properties. In this paper, we prepared two liquid crystal/carbon nanotubes composites through doping, and characterized them.(1) In present work, the MPPB nanocomposites with various concentration MWNTs were prepared by melt mixing to investigate the effect of MWNT doping, via polarized optical microscopy (POM), thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), Raman spectroscopy and surface resistance respectively. From the results, the MWNTs were well dispersed in host matrix at low concentration. The LC director field was influenced by the MWNT aggregates which probably acted as the nucleation centres. The sample presented a highly performance in electrical conductivity, expressed as the decrease in surface resistance. For the nanocomposites, no improvement in thermal stability was seen at the initial state of degradation.(2) We synthesized a TLCP via high-temperature solution polycondensation and prepared various concentrations of TLCP/MWNTs by in situ polymerization. Differential scanning calorimetry (DSC), TGA, X-ray diffraction (XRD) and POM were used to investigate the thermal behavior, crystalline structure and liquid crystalline properties of the pure TLCP and TLCP/MWNTs nanocomposites. SEM images showed that the MWNTs were well separated in the TLCP matrix. The X-ray diffraction results suggested that the addition of MWNTs to TLCP did not significantly change the crystal structure of TLCP matrix. The TGA indicated that a small amount of MWNTs could improve the thermal stability of TLCP domains.