Mechanical, thermal and morphological studies of epoxidized palm oil / unsaturated polyester / montmorillonite composites

Abstract

Nanocomposite consisting of natural fibre reinforced thermoset/vegetable oil/montmorillonite (MMT) nanofiller resin is among the latest technologies in nanocomposites production. It has contributed to better environment and increase the sustainability of the composite materials. To tap the abundance of palm oil in Malaysia, this study was conducted to produce a novel composite of kenaf fibre reinforced unsaturated polyester (UPE)/epoxidized palm oil (EPO)/MMT by resin transfer moulding (RTM) followed by oven curing. Benzoyl peroxide was used as an initiator and the composition was kept constant at 1.5 phr. The compositions of UPE/EPO resin were varied at 90/10, 80/20, 70/30 wt % and the MMT nanoclay were varied at 1, 1.5 and 2 phr for each formulation. The effects of different loading ratios of EPO and MMT in UPE/EPO/MMT and the different RTM mould angles in kenaf fibre reinforced UPE/EPO/MMT composite were studied in particular mechanical, morphology, thermal, and water absorption properties of the resin and composite. Pre-characterisations of UPE/EPO resin were carried out using Fourier transform infrared spectroscopy and differential scanning calorimetry. The results revealed that the oxirane rings of EPO were successfully opened and the resin successfully crosslinked at applied curing temperature. The addition of EPO has caused a decrease in glass transition temperature, tensile, flexural properties and an increase in elongation at break and impact strength, which indicated an increase in mobility and toughness of UPE chain. UPE/EPO blends also exhibited higher thermal stability than neat UPE. The addition of MMT nanoclay enhanced the mechanical and thermal properties of the resin. The optimum balance properties were obtained for UPE at 10 wt % EPO and 1.5 phr MMT nanoclay loadings. The best formulation was then carried out at 0º, 30º and 45º RTM mould angle with kenaf fibre reinforcement. 30º RTM mould angle gave the highest mechanical and thermal properties of the resulted kenaf fibre reinforced UPE/EPO/MMT composite.