Plant‐Derived Polyphenols for Sustainable Flame‐Retardant Coatings

Polyphenolic flame‐retardant (FR) systems have attracted growing attention as promising candidates that can simultaneously address environmental sustainability and fire safety requirements. This review comprehensively analyzes their operating mechanisms and application performance through a comparative assessment of the literature. Representative polyphenolic materials—including lignin, polydopamine, tannic acid, flavonoids, and related phenolics—are examined with respect to char formation, radical scavenging, metal‐ion coordination, surface protection mechanisms, and synergistic effects with inorganic or organic coadditives. Their FR efficacy, durability, and stability are compared across diverse substrates, including polymers, wood, fibers, and coatings, with emphasis on biodegradability, renewability, and environmental safety. Furthermore, life cycle assessment (LCA) and safe‐and‐sustainable‐by‐design (SSbD) frameworks are applied to evaluate their alignment with circular economy principles. Collectively, this review clarifies the opportunities and limitations of polyphenolic FR systems and highlights their potential as sustainable candidates for next‐generation fire mitigation technologies.