Evaluation of the mechanical properties of carbon fiber/polymer resin interfaces by molecular simulation

Herein, we evaluate the mechanical properties of carbon fiber/polymer interfaces using three types of specimens: carbon fiber/vinyl ester resin, carbon fiber/epoxy resin, and carbon fiber/polyimide resin. Microbonding tests were performed and the fiber load at interfacial debonding was obtained. By performing finite element analysis, the true interfacial strengths were determined. The strength values followed the order: polyimide > epoxy > vinyl ester for the specimens tested. Molecular modeling was also performed for these specimens. Three stacked graphene layers were used to represent the carbon fiber surface and the interfacial energy was determined. The interfacial energy of the three systems followed the same order as the strength values. The molecular simulations allowed for a qualitative discussion of the material properties. In addition, an interfacial debonding simulation was performed, however the resin part failed instead of the interface, indicating that we evaluated the resin strength but not the interfacial strength. For the quantitative evaluation of interfacial debonding strength, further studies are necessary.