Functionalization strategies for sustainable plant fiber composites: A comprehensive review of techniques, performance and future directions
Hassan Tawsif Tazwar, Maisha Farzana Antora, Md Zillur Rahman
Abstract
Plant fiber-reinforced polymer composites (PFRCs) have emerged as promising, sustainable alternatives to synthetic fiber composites due to their biodegradability, low environmental impact, and renewable nature. However, their widespread adoption is hindered by intrinsic challenges such as poor fiber-matrix interfacial bonding, hydrophilicity, and variability in fiber quality. This review comprehensively evaluates recent advancements in functionalization strategies, including chemical, physical, biological, and hybrid approaches, to improve the structural and environmental performance of PFRCs. The review emphasizes how these modifications influence mechanical strength, thermal stability, and moisture resistance. It also assesses their environmental compatibility, scalability, and industrial relevance. Currently, chemical treatments are the most effective for enhancing interfacial adhesion, yet often involve trade-offs in toxicity and sustainability. In contrast, biological and hybrid methods are gaining prominence for offering multifunctionality with reduced ecological impact. The review further highlights the need for regionally adaptable, low-cost, and circular functionalization techniques to meet industrial processing demands. Future research directions are proposed to integrate green functionalization methods into scalable manufacturing platforms, enabling PFRCs to serve as viable materials across high-performance sectors such as construction, automotive, biomedical, and packaging. By addressing these critical gaps, this review offers a strategic framework for advancing PFRCs as next-generation bio-based composites aligned with global sustainability goals.