The effects of carbon fiber surface treatment by oxidation process for enhanced mechanical properties of carbon fiber/epoxy composites for biomedical application

In this research, the production of carbon fiber composite (CFC) with epoxy resin was carried out for biomedical application. The surface of the carbon fibers was previously oxidized with concentrated nitric acid at a temperature of 100 °C for 30–120 min to create a rough surface impression on the carbon fibers to enhance interfacial bonding in the composite, increase surface area, and reduce surface tension. The carbon fiber/epoxy composite was fabricated using the vacuum assisted resin infusion method. Characterization of the oxidized carbon fibers and the composite products was performed using a digital microscope, scanning electron microscope, and Fourier Transform Infrared (FTIR) analysis. FTIR analysis results indicated that the carbon fiber oxidation process introduced new chemical functional groups, such as –CN and –CO groups. Mechanical characterizations included tensile testing of non-oxidized and oxidized carbon fiber and tensile testing of carbon fiber/epoxy composite. The results showed that the composite formed from oxidized carbon fibers/epoxy resin exhibited higher tensile strength compared to non-oxidized CFC. The longer the carbon fiber oxidation process, the higher the tensile strength values obtained.