Study on toughening modification of epoxy resin and its properties of T700 carbon fibre composites

The extremely cross-linked structure of the cured epoxy resin makes it fragile. This work toughened the N,N-diglycidyl-4-glycidyloxyaniline (AFG-90H)/methyl nadic anhydride (MNA)/2-ethyl-4-methylimi-dazole (2E4MZ) resin matrix with different curing agent and epoxy resin. The effects of the introduction of methyl hexahydrophthalic anhydride (MeHHPA) and bisphenol F-type epoxy resin (8220) on the curing kinetics, heat resistance, and mechanical properties of the casting body were investigated. The modified resin matrix was used to manufacture high-performance composites. The mechanical characteristics and interfacial behaviours of the composites were examined using the NOL ring test, laminate test, and fracture morphology observation. The results show that when the resin matrix possesses strength and toughness when the mass ratios of MNA to MeHHPA is 1:2 and AFG-90H to 8220 is 7:3, and the tensile strength of the resin casting body reached 87.2 MPa, the bending strength reached 129 MPa, the impact strength reached 21.8 KJ/m 2 ,the elongation at break was 3.76%. The laminate has a tensile strength of 1.84 GPa and a bending strength of 949 MPa. The NOL ring has a tensile strength of 2.53 GPa and an interlaminar shear strength of 80.2 MPa. Compared to other T700 carbon fibre composites, the composites in this paper have superior properties.