A Review of Natural Fibers: Classification, Composition, Extraction, Treatments, and Applications

This review provides a comprehensive analysis of natural fibers, addressing their classification, chemical composition, extraction methods, treatments, and diverse applications. It categorizes natural fibers into plant-based (cellulose-rich), animal-based (protein-based), and mineral-based types, detailing their unique structural and chemical properties. The paper examines traditional and advanced extraction techniques—including dew, water, enzymatic, chemical retting, and mechanical decortication—highlighting their impact on fiber quality and environmental sustainability. Furthermore, it reviews various chemical and biopolymer treatments designed to enhance fiber performance, reduce hydrophilicity, and improve adhesion in composite materials. The discussion extends to the multifaceted applications of natural fibers across industries such as textiles, automotive, construction, and packaging, underscoring their role in reducing reliance on synthetic materials and promoting eco-friendly innovations. The review synthesizes recent market trends and emerging fiber classifications, emphasizing the potential of natural fibers to drive sustainable development and informing future research in extraction efficiency, treatment optimization, and lifecycle analysis.