Natural Cellulose Fiber-Reinforced Biopolymer Composites: Extraction Methods, Properties, and Applications

The growing demand for sustainable and eco-friendly materials has intensified interest in natural fibers as renewable biopolymer-based alternatives. Among these, cellulose fibers are widely recognized for their biodegradability, cost-effectiveness, and versatility across applications, including textiles, packaging, food preservation, wastewater treatment, medicine, and cosmetics. Optimizing the intrinsic properties of natural fibers is critical to expanding their utility in advanced and high-performance applications. Chemical, physical, and biological treatments have been employed to enhance mechanical strength, thermal stability, moisture resistance, flame retardancy, UV protection, and antimicrobial activity. For instance, alkaline treatment can improve tensile strength by up to 40%, while hybrid surface modifications can enhance thermal and moisture resistance by 25–35%. Characterization techniques such as FTIR, SEM, and XRD provide insights into the correlation between processing conditions and fiber performance. Future research should focus on green, cost-effective modification strategies, incorporation of nanocellulose, and hybrid polymer approaches to further elevate fiber functionality and enable scalable industrial adoption. Strengthening these strategies will facilitate large-scale production of high-performance natural fiber composites, promoting sustainable innovation in packaging, construction, and automotive sectors. This review critically evaluates current advancements, identifies research gaps, and offers perspectives for developing environmentally responsible and industrially translatable fiber modification technologies.