Evaluating the Effect of Biosilica on the Properties of Rosin‐Based Eco‐Friendly Flame Retardants

Abstract Improving the fire resistance of polymeric matrices frequently requires incorporating specialized additives. Nevertheless, conventional solutions present significant challenges, including high costs, limited availability, the release of toxic gases, the emission of carcinogenic substances, and limited effectiveness in flame suppression. Silica compounds from rice husks demonstrate excellent thermal stability without the usual disadvantages of conventional flame retardants, positioning them as a eco‐friendly alternative. This study evaluates the incorporation of biosilica into a rosin matrix at various weight percentages (wt%) to develop composites with enhanced flame resistance. The visual analysis indicated that composites up to 20 wt% biosilica exhibited homogeneous structures. Scanning electron microscopy (SEM) analyses revealed uniform biosilica distribution at 10 wt%, transitioning micro‐aggregation and increasing surface roughness at higher concentrations. Fourier Transform Infrared Spectroscopy (FTIR) showed increased biosilica concentration and enhanced rosin‐biosilica interactions, shore hardness, and density. The water absorption and contact angle experienced a more severe reduction between 10 and 15 wt% biosilica. By adding biosilica, the composites' flame retardancy increased, and their burning rates decreased, more markedly at 15 and 20 wt% biosilica. The results indicate biosilica exhibits potential as an effective flame retardant agent for polymers, thereby presenting a sustainable alternative that aligns with environmentally friendly practices.