Thermal decomposition behavior of carbon nanotube reinforced thermotropic liquid crystalline polymers

摘要

Thermotropic liquid crystalline polymers (TLCP), 4-hydroxybenzoic acid (HBA)/6-hydroxyl-2-naphthoic acid (HNA) copolyester, and HNA/hydroxylbenzoic acid (HAA)/terephthalic acid (TA) copolyester reinforced by carbon nanotube (CNT) were prepared by melt compounding using Hakke internal mixer. The thermal behavior and degradation of CNT reinforced HBA/HNA copolyester and HNA/HAA/TA copolyester have been investigated by dynamic thermogravimetric analysis under nitrogen atmosphere in the temperature range 30 to 800°C to study the effect of CNT on the thermal decomposition behavior of the TLCP/CNT nanocomposites. The thermal decomposition temperature at the maximum rate, residual yield, integral procedural decomposition temperature, and activation energy for thermal decomposition was studied to investigate thermal stability of TLCP/CNT nanocomposites. The thermal stability of CNT reinforced HBA/HNA copolyester was increased by addition of a very small quantity of CNT and the residual weight was 42.4 and increased until 50.8 as increasing CNT contents. However, the thermal stability of CNT reinforced HNA/HAA/TA copolyester was decreased initially when a very small quantity of CNT added. The residual weight was decreased from 50.4 to 45.1. After addition of CNTs in the TLCP matrix, the thermal stability of CNT reinforced HNA/HAA/TA copolyester increased as increasing content of CNT and the residual weight was increased until 53 as increasing CNT contents. The activation energy was calculated by multiple heating rate equations such as Friedman, Flynn-Wall-Ozawa, Kissinger, and Kim-Park methods to confirm the effect of CNT in two different TLCP matrices.