Toughening epoxy resins by liquid crystalline co-polyester PET-PHB

The toughness of the epoxy resins is modified by liquid crystalline copolyester PET-PHB. The morphologies of the fracture surface were observed by scanning electron microscope (SEM). The relationships between the morphologies and mechanical properties were discussed. The results revealed that the moduli, tensile and impact strengths of the modified epoxy resins are much higher than those of the unmodified epoxy resin. The maximum values have been reached in the tensile and impact strength of the modified epoxy resins by adding PET-PHB copolyester of 10%. At the same time, an uniformly network microstructure emerged on the fracture surface of the toughened epoxy resins, which is obviously different from that of unmodified epoxy resin. It is believed that the formation of the uniformly network microstructure results in the significant improvement of impact and tensile strength of the epoxy resins.