Functionalization of Multiwalled Carbon Nanotubes with Thermotropic Liquid-Crystalline Polymer and Thermal Properties of Composites

A novel high-performance multiwalled carbon nanotube (MWCNT) nanocomposite (MWCNT-TLCP) was prepared using an in situ polycondensation approach by grafting a thermotropic liquid-crystalline polymer (TLCP) onto the sidewalls of MWCNTs functionalized with hydroxyphenyl groups. FTIR spectroscopy revealed that TLCP was covalently attached to the MWCNTs, and Raman signals corresponding to the D- and G-bands of MWCNTs were attenuated after functionalization. TEM and TGA results showed that the average thicknesses of grafted TLCP layers on the MWCNT surface were 5-7 nm, and the amount of grafted TLCP was about 56 wt %. The morphology of MWCNT-TLCP/TLCP composite containing 3 wt liquid-crystalline polymer-modified MWCNTs was examined by SEM. SEM images of the composite fracture surfaces showed a homogeneous dispersion of the MWCNT-TLCP nanocomposite in the TLCP matrix. The mesophase temperature region of the composite was obviously increased because of the presence of functionalized MWCNTs.