Bio-based flame-retardant textiles: Materials, functionalization, thermal performance, and applications

The growing demand for safer and more sustainable fire protection has increased interest in bio-based Flame-Retardant (FR) materials for textiles. Unlike conventional halogenated chemicals, which raise issues of toxicity and long-term environmental impact, bio-based flame-retardant materials provide renewable and eco-friendly alternatives. This review provides an in-depth overview of recent eco-innovations in bio-based FRs, focusing on their natural sources, functional properties, and the mechanisms responsible for flame retardancy. Plant extracts, animal-based, and agricultural by-products are more generally preferred for their ability to provide effective fire protection while maintaining sustainability. Developments in processing methods, including layer-by-layer assembly, sol–gel treatments, and hybrid coatings, are highlighted as key strategies to improve durability, scalability, and multifunctional performance. Applications include protective clothing, industrial textiles, and emerging smart fabrics, where added functions such as antimicrobial activity, water repellency, and UV protection are increasingly important. The review also highlights key challenges, including high cost, limited durability, and regulatory limitations, and points to future research directions toward biodegradable, multifunctional, and circular-economy-based FR systems. By bridging materials innovation with environmental priorities, it highlights pathways to safer, greener, and more durable fire-protective textiles.