Enhanced thermal stability and long-term mechanical durability at elevated temperatures of thermotropic liquid crystal polyester/glass fiber composites

We herein report the influences of glass fibers (GFs) on the thermal stability and long-term mechanical performance at elevated temperatures of thermotropic liquid crystal polyester (TLCP) composites for advanced applications in the industrial sectors of automotive, electric/electronics, aerospace, and construction. For this purpose, TLCP-based composites with 10–40 wt% GF loadings are fabricated by facile melt-mixing and injection-molding. The scanning electron microscopy (SEM) images and X-ray diffraction patterns demonstrate that the GFs are dispersed in the TLCP matrix with a microfibrillar structure. The specific interactions between TLCP and GFs in the composites are identified by ATR FT-IR spectroscopic analyses. The thermal degradation temperatures of the composites increase slightly with the increment of GFs with high thermal stability and heat capacity. The long-term mechanical durability of TLCP/GF composites at 150 °C is analyzed by obtaining time-dependent storage modulus master curves based on the stepped isothermal method and time–temperature superposition principle. The dynamic mechanical moduli, activation energy, and long-term mechanical durability are found to be highly enhanced for TLCP composites with higher GF loadings, which is owing to the efficient stress transfer from the TLCP matrix to reinforcing GF fillers via specific interactions at the composite interface.