Hybridization effect of cellulose paper and postcuring conditions on the mechanical properties of flax fiber reinforced epoxy biocomposite

An ever-increasing rise in demand for sustainable materials has received significant attention in developing biocomposites for structural applications. In this regard, natural fibers replacing synthetic fibers as reinforcement in epoxy composite could be a significant gain toward sustainability, especially in automobile and structural applications. Herein, flax fiber/cellulose paper-reinforced epoxy biocomposite (FREC-X) was fabricated via a vacuum infusion process. The influence of postcuring conditions (time and temperature) and cellulose paper density on the mechanical properties of FREC-X was studied. The tensile strength and modulus of FREC-X increased by 37% and 64%, respectively, upon the integration of paper. Postcuring FREC-X further augmented the tensile and flexural properties of the composite, which could be attributed to the increase in cross-linking of the epoxy and yields a strong polymer network. Fractography analysis confirmed that the composites integrated with paper showed fewer defects with improved interfacial adhesion. In addition, the water absorption and thickness swelling results revealed that the presence of cellulose paper marginally increased the water uptake and thickness swelling of FREC-X. Furthermore, there was no significant change in the tensile and flexural properties of FREC-X observed even after immersing in water for >200 h. Such properties of FREC-X seen as a fascinating alternative to synthetic fibers and petroleum-based epoxy and are promising material for sustainable development.