Highly Transparent Fire-resistant Coatings with Intumescent Three-source Integration

Abstract

Wood, a readily available and sustainable natural resource, has found widespread use in construction and furniture. However, its inherent flammability poses a potential fire risk. Although intumescent fire-retardant coatings effectively mitigate this risk, achieving high transparency in such coatings presents a significant challenge. In our approach, we employed a cross-linked network of phytic acid anion and N-[3-(trimethoxysilyl) propyl]-N,N,N-trimethylammonium cation to create a transparent “three-in-one” intumescent coating. The collaborative P/N/Si flame-retardant effect markedly improved the intumescent char-forming capability, preventing the wood from rapid decomposition. This resulted in a substantial reduction in heat release (13.9% decrease in THR) and an increased limiting oxygen index (LOI) value of 35.5%. Crucially, the high transparency of the coating ensured minimal impact on the wood’s appearance, allowing the natural wood grains to remain clearly visible. This innovative approach provides a straightforward method for developing transparent intumescent flame-retardant coatings suitable for wooden substrates. The potential applications extend to preserving ancient buildings and heritage conservation efforts.