Improvements in thermal, mechanical, and dielectric properties of epoxy resin by chemical modification with a novel amino-terminated liquid-crystalline copoly(ester amide)

We used a novel amino end-capped aromatic liquid crystalline copoly(ester amide) (LCP) to improve the thermal and mechanical properties of glycidyl end-caped poly(bisphenol A-co-epichlorohydrin) (DGEBA) cured with 4,4′-diaminodiphenylsulfone (DDS). The thermal and mechanical properties of the blends were investigated as a function of LCP loading. Upon addition of 10 phr of LCP, the impact strength of the modified epoxy was dramatically increased from 35.8 J/m to 51.8 J/m, which is an approximately 30% improvement compared to the un-modified system. In addition, an increase in the fracture toughness and decreases in the dielectric constant and the dielectric loss were found with increases in LCP loading in the blend. These improvements were achieved even when LCP was dispersed in an epoxy network within a homophase structure.