The efficacy of nanoclay loading in the medium velocity impact resistance of kenaf/PLA biocomposites

Abstract

This work focused on investigating the efficacy of clay nanoparticles loading in the medium velocity impact resistance of kenaf/polylactic acid (PLA) biocomposites. Kenaf/PLA biocomposites with different nanoclay loadings of 0, 3, 5 and 7% by weight were fabricated and their medium velocity impact resistance tested on a gas gun. Results indicate that the addition of nanoclay in the biocomposites improved the medium velocity impact resistance of the biocomposites, specifically the perforation threshold limit, energy absorbed, crack and damage resistance. Improvements on these properties were thought to be due to enhancements brought about by the nanoclays on interfacial bonding and microstructural properties of the biocomposites revealed through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The nanoclays reduced the micro-voids thereby improving bonding between PLA and kenaf fibres. SEM–EDX analysis detected silicon and aluminium elements which were from the nanoclays and the elemental maps showed that all the elements were uniformly distributed in all cases with good dispersion of the nanoclays. However, incidences of nanoclay agglomeration were observed at 7 wt% nanoclay content which had adverse effects on the biocomposites properties. Optimum results were achieved with 5 wt% nanoclay content, beyond which a reduction in the medium velocity impact resistance was observed. The perforation threshold, energy absorption capacity, resistance to damage and prevention of crack propagation increased by 41.9, 109, 26.5 and 28.9%, respectively, at the 5 wt% nanoclay content level. The study shows that the addition of nanoclay improves the impact properties of kenaf/PLA biocomposites within the medium velocity range. The novel nanoclay impregnated biocomposite material developed is suitable for applications where good impact properties are required.