The effect of hybridization on thermal and mechanical properties of glass/oxidized PAN fibers-polymer composites

Fibers hybridization is one of the most effective ways to facilitate the use of the new fibers as reinforcement in composite materials. In this study, oxidized polyacrylonitrile fibers (OPFs) and glass fibers were hybridized in a polymer matrix through hand lay-up method by arranging the fibers in different layering sequences. The hybridization effects of fibers on thermal and mechanical properties of the polymer matrix composites were investigated by thermal analysis, horizontal burning, tensile and flexural testes. It was found that by increasing the OPFs to glass fibers ratio, tensile strength, elastic and flexural modulus and flexural stress were decreased, whereas failure strain followed a different trend. Also, hybridization of OPFs and glass fibers in composites led to decreasing the burning rate and consequently, increasing fire retardancy. The obtained thermogravimetric analysis results also demonstrated that maximum and minimum amounts of char residue at 900 °C were related to the composites reinforced with four layers of glass fibers and OPFs, respectively. Based on the results of derivative thermogravimetric (DTG), by increasing the OPFs to glass fibers ratio, DTG curves were shifted to higher temperatures.