Recent advances in fiber pretreatment for plant fiber-reinforced PLA biocomposites: Interfacial tailoring, properties, and applications

Plant fiber-reinforced biocomposites have emerged as promising sustainable materials for industrial and biomedical applications. However, the intrinsic incompatibility between hydrophilic plant fibers and hydrophobic polymer matrices (e.g., PLA) remains a major challenge limiting their composite performance. Recent advances in fiber pretreatment technologies have shown significant potential in enhancing interfacial adhesion and improving mechanical, thermal, and tribological properties of PLA-based composites. This review critically assesses both physical (e.g., steam explosion, plasma treatment) and chemical (e.g., alkali treatment, silane coupling, acetylation) strategies for fiber modification. The effectiveness of these methods is discussed in terms of interface chemistry, composite morphology, and long-term performance. Remaining challenges, including moisture sensitivity, limited durability, and cost constraints, are highlighted, along with prospects for scalable, multifunctional biocomposites tailored for high-performance applications.