Recent advances on improving the mechanical and thermal properties of kenaf fibers/engineering thermoplastic composites using novel coating techniques: a review

Natural fiber-reinforced polymer composites are presently receiving the attention of scholars and industrialists due to their specific properties, such as being naturally eco-friendly, biodegradable, economical, viable, available, and sustainable. The key problems associated with natural fiber polymer composites, including fiber/matrix compatibility, high moisture absorption, and, especially, thermal degradation in engineering plastics (high-temperature plastics), constitute the most critical thrust of this review. It is noted that at high temperatures, natural fibers degrade and this has adversely restricted their usage with only commodity thermoplastics having relatively low melting temperatures, such as polypropylene (PP) and polyethylene (PE). This review paper, therefore, provides valuable research highlights on utilizing and improving the mechanical and thermal properties of natural kenaf fibers as reinforcement in engineering polymer composites for high-temperature engineering applications using polymer matrices, such as polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), and polyphenylene ether (PPE). The initial and various chemical treatments of natural fibers, their effect on the thermal and performance properties of natural fiber engineering thermoplastic composites, and the advanced treatment of epoxy coatings are reviewed. Applications of natural fiber-reinforced thermoplastic composites in the construction and automotive industries, as well as in other applications, are outlined. It was established that the adhesion and thermal stabilities between polymer matrix and natural fibers are better improved by surface coating with diluted epoxy resin thermoset. This eventually improved the overall thermal and performance properties of the resultant composites and will serve as a data bank and guide for manufacturers and future research directions using high-end engineering polymers with higher processing temperatures.

Automated summary

Natural fiber-reinforced polymer composites have gained attention for their eco-friendly, biodegradable, economical properties. However, the thermal degradation of natural fibers limits their usage with high-temperature plastics. This review highlights the use of natural kenaf fibers as reinforcement in engineering polymer composites for high-temperature applications, focusing on the effects of chemical treatments and surface coatings.