Thermal and mechanical properties of hybrid carbon/oxidized polyacrylonitrile fibers‐epoxy composites

Nowadays, hybrid composites are one of the important materials in industry due to their special properties. In this research, hybrid oxidized polyacrylonitrile (PAN) and carbon fibers reinforcement were used in epoxy matrix. The hybrid composites were fabricated using the hand lay-up technique by placing the reinforcements in different layering sequences. Thermal and mechanical properties of these hybrid composites were investigated by thermal analysis, horizontal burning, tensile and bending tests. The tensile test results indicated that increasing oxidized polyacrylonitrile fibers (OPFs) to carbon fibers ratio decreased tensile strength and elastic modulus, but increased failure strain. Hybrid oxidized PAN and carbon fibers reinforcement in composites led to decreasing flexural stress and modulus, and increasing flame retardancy. Thermal analysis results also showed that the maximum rate of mass loss in all composites was 370.6˚C. It was also found that the maximum and minimum amounts of char residue at 900°C were related to the composites with four layers of carbon and OPFs, respectively.