Mechanical and thermal properties of mesogen-jacketed liquid crystalline polymer/epoxy resin composites

The effects of mesogen-jacketed liquid crystalline polymer poly(dipropyl vinylterephthalate) (PDPVT) on the mechanical and thermal properties of diglycidyl ether of bisphenol-A (DGEBA) epoxy resin were investigated by impact test, tensile test and thermogravimetric analysis (TGA). The mechanism underlying the enhancement of mechanical properties of epoxy resin was studied using 1D wide-angle X-ray diffraction (WAXD) and scanning electron microscope (SEM). It was found that the mechanical properties of 1 wt%–5 wt% PDPVT/DGEBA composites were significantly improved compared to neat epoxy resin. Especially, the epoxy resin with 3 wt% PDPVT had the greatest increase in mechanical properties, with the impact strength, tensile strength and elongation while breaking increased by 87%, 59% and 174%, respectively. The increased mechanical strength was due to the fact that PDPVT maintained liquid crystalline phase in cured PDPVT/DGEBA composites, which would blunt the crack tip and prevent crack propagation. Moreover, PDPVT had slight effect on the thermal stability properties of epoxy resin.