The Use of Kenaf Fibre as a Natural Anti-Degradant in Recycled High-Density Polyethylene and Natural Rubber-Based Thermoplastic Elastomers

As most plastic materials disintegrate without being properly reused after they are discarded, this present study developed a novel thermoplastic elastomer (TPE) using recycled high-density polyethylene (rHDPE) and natural rubber (NR) with kenaf fibre as a sustainable filler. Apart from being used as filler, this present study aimed to examine the use of kenaf fibre as a natural anti-degradant as well. The results indicated that the tensile strength of the samples was found to have significantly decreased after 6 months of natural weathering and had decreased by a further 30% after 12 months due to the chain scission of the polymeric backbones and the degradation of the kenaf fibre. However, the composites that contained kenaf fibre significantly retained their properties post-natural weathering. In terms of tensile strength and elongation at the break, the addition of only 10 phr of kenaf increased the retention properties by 25% and 5%, respectively. This is noteworthy as kenaf fibre also contains a certain amount of natural anti-degradants. Therefore, as the kenaf fibre improves the weather resistance of composites, plastic manufacturers could use it as either a filler or a natural anti-degradant.