Abstract: Epoxy resin is widely used in coatings, electronic packaging materials and adhesives because of its strong adhesive strength and good thermal stability, but its high cross-linking density also brings the problem of brittleness and poor toughness, which has become the main factor restricting its development and application. A high performance epoxy resin (TDE-85) was modified by biphenyl epoxy resin 3,3′,5,5′ -tetramethylbiphenyl bisphenol diglycidyl ether (TMBP) with 3,3′ -diaminodiphenyl sulfone (3,3′-DDS) as curing agent by melt blending method. The mechanical properties of the modified resin system were studied. The results of polarizing microscope and SEM showed that the liquid crystal structure could be well dispersed in the epoxy resin matrix and strengthened and toughened. The results show that when the TMBP content is 6wt%, the mechanical properties of the cured material are obviously improved, the impact strength and flexural strength are increased by 30% and 27% respectively, and the strength and toughness is obviously improved. When the TMBP content is 4wt%, the tensile strength and tensile modulus reach the maximum of 93.69 MPa and 5.39 GPa.

Key words: epoxy resin, thermal properties, mechanical properties, blending modification, liquid crystal structure, composites