Recent advances in sustainable natural fiber composites: Environmental benefits, applications, and future prospects

Natural fiber composites refer to the blends of plant and animal fibers that are renewable as well as biodegradable and require low energy in their manufacturing, unlike man-made plastics. In this review, five large categories of natural fibers, jute, flax, hemp, wool, and silk, are addressed in terms of environmental production and functionality as well as industrial preparedness on the basis of carbon reduction targets and the strategies of the circular economy. NFCs are contrasted based on their cleanliness of production, robustness, and usability with a new triple-pronged analytical framework. Some of the more recent innovations are the hybrid composites, green processing, as well as using agricultural waste as raw materials. Up to 80 % carbon reduction can be achieved with NFCs, as well as reduced energy required in manufacturing and competitive performance through surface treatments, hybridization, or AI-driven design tools. Nevertheless, the deficiency in the use on a high scale is property variability and moisture sensitivity. It has potential in car interiors, panel systems in buildings, packages, and consumer products. The new technology, like the Digital Twin systems and predictive models, is promising in improved management of lifecycles. This study helps to transition the world toward green materials and less reliance on non-renewable resources by informing about the research gaps and presenting the future direction on the subject. Unlike previous reviews, this work integrates both plant- and animal-based fibers, systematically compares their mechanical and environmental performance, and highlights recent developments such as hybrid composites, waste valorization, and digital tools (AI and Digital Twin). This comprehensive scope offers a unique framework to understand current challenges, emerging solutions, and prospects of NFCs.