Interlaminar Toughening of CFRP Composites with Modified ZnO Cohesive Films

The influence of cohesive films toughened with modified nano-ZnO particles on the mechanical properties of thermoset-epoxy-based composite was investigated. Nano-ZnO is first modified by coupling agent to obtain modified nano-ZnO, which was added into epoxy resin as nanofiller. By blending modified nano-ZnO particles at different mass ratios from 0 to 4% in the presence of a curing agent, some cohesive films with different interlaminar properties were formed between the two interfacial surfaces in a composite specimen, which have been applied in end-notched flexure (ENF) tests and double cantilever beam (DCB) tests. A series of finite element (FE) models, together with the predetermined model parameters, were built to assess the influence of modified nano-ZnO and curing agent. The results show that, for the toughened beam (with 4 wt % modified nano-ZnO and 2 wt % GEL2-B2), the critical loads of ENF tests and DCB tests increases by 30.25 and 68.40%, respectively.