Mechanical, physical and thermal properties of natural fibre reinforced epoxy composites

Abstract

There has been expanded effort to offer eco-friendly and biodegradable materials for the next generation of automotive applications due to global environmental concerns and increased awareness of renewable green resources. Currently, polystyrene foam has been used as one of the core insulation material in refrigerated vehicle body which is non-biodegradable and highly polluting resource. There were limited study on utilizing natural fibre in refrigerated vehicle application. Thus, to fill this research gap, current efforts are being made to produce biodegradable and renewable resource composites with the use of palm oil fibre and kenaf fibre in the epoxy resin as a matrix constituent. The objectives of this study were to fabricate palm oil fibre and kenaf fibre reinforced epoxy resin via vacuum infusion techniques based on volume fraction of fibres and alkaline treatment. Then, tensile, water absorption, thermal conductivity and morphologies properties were evaluated and compared with the existing core insulation material (polystyrene foam). As such, the natural fibre composite was fabricated based on two parameters, namely fibre content (20, 30, and 40 vol.%) and 5 w/v% of NaOH solution using vacuum infusion method. The mechanical, physical and thermal properties of fabricated untreated and treated palm oil fibre (UPOF and TPOF) as well as kenaf fibre (UKF and TKF) composites were investigated. From the viewpoint of mechanical performance, 40TPOF showed the highest tensile strength and tensile modulus with the values of 35.89 MPa and 6.39 GPa, respectively. Alkaline treated fibre composite is indeed has increased the values of tensile strength and tensile modulus. It has been proven by the good interfacial adhesion between fibres and matrix detected by SEM morphology. Meanwhile, from the physical perspective, 20TPOF was found to have the lowest water absorption with the values of 1.43%. The use of treated composites increases the number of possible reaction sites on the surface of the fibre and promotes better interfacial bonding within the composite. Fibre adhesion is improved, resulting in dimensionally stable structures. As a result, no voids were observed by using the optical microscope. Besides, the lowest thermal conductivity was 40UPOF with value of 0.079 W/mK. The study of these materials leads to the conclusion that increasing the fibre loading reduces the thermal conductivity of a composite material. The fabrication of the suggested parameters was performed where the obtained values are compared with values of the polystyrene foam. 20TPOF was found to be the most suitable core insulation material with the tensile strength, tensile modulus, water absorption, thermal conductivity values of 25.37 MPa, 3.88 GPa, 1.43% and 0.098 W/mK, respectively. The tensile strength, tensile modulus, and water absorption values have been improved by 97.64%, 99.38%, and 4.67%, respectively compared to the polystyrene foam. Meanwhile, the thermal values obtained for 20TPOF was considered as one of the insulator material. Therefore, this study offers the great potential of the utilization of palm oil fibre and kenaf fibre composites in automotive applications, specifically the core insulation material of refrigerated vehicle body.