Surface treatment of natural fibers for enhancing interfacial adhesion and mechanical properties in biocomposites - a comprehensive review
Midhun Varma, Sharan Chandran M
Abstract
Natural fiber-reinforced composites are receiving enormous attention as sustainable replacements for conventional synthetic composites. Natural fibers are, however, hydrophilic in nature and tend to experience weak interface bonding with hydrophobic matrices, influencing the mechanical performance of composites. Numerous surface treatments have been applied to improve the fiber–matrix interface adhesion. This review aims to examine various natural fiber surface treatment techniques developed to enhance the interface bond between fiber and matrix in composite materials. Recent advances in chemical, physical, and biological treatments are discussed with a focus on their mechanisms, effects on fiber surface properties, and influence on composite interface bonding and mechanical properties. Chemical treatments, including alkali, silane, acetylation, and benzoylation, removes impurities and increase the surface roughness of natural fibers. Plasma and other physical treatments modify the surface energy without impacting the bulk fiber properties. Plasma treatment is effective in improving fiber crystallinity, wettability, and mechanical properties. Future work may be focused on hybrid treatment, nanocoatings, and environmentally friendly processes to achieve high fiber performance and sustain environmental advantage. This paper presents current trends, potential for improvements in various surface treatments, and prospects of natural fiber surface treatments for composite applications in various sectors.