Breakthrough Silicone-Based Coating Enhances Fire Protection Performance
Intumescent flame-retardant (IFR) coatings play a vital role in reducing fire risks, but conventional systems often struggle with complex formulations, limited high-temperature durability, and poor substrate compatibility. A recent study presents an innovative IFR coating system built on runaway hydrosilylation polymerisation, offering a more efficient and robust solution.
The new approach uses tetravinylcyclotetrasiloxane (V4) and 1,3,5,7-tetramethylcyclotetrasiloxane (H4) to form a polymer known as polyH4V4. This material demonstrates exceptionally high cross-linking density and strong thermal stability, effectively overcoming key limitations of traditional flame-retardant coatings.
When exposed to heat, the polymer undergoes runaway polymerisation, generating gases that rapidly expand the coating into a porous and thermally stable protective layer. This expansion significantly improves heat shielding and protects underlying materials. The addition of vinyl-functionalised polymethylvinylsiloxane (PMVS) further enhances performance, enabling up to 3.7 times greater expansion compared to the base polymer. In fire tests, coated wood substrates showed more than double the charring time, highlighting the coating’s effectiveness.
Further analysis using advanced techniques such as XPS and TG-FTIR revealed that the material forms a ceramic-like silicon oxycarbide (SiOC) structure during thermal degradation. This process leaves over 80% residue at 800°C, contributing to its excellent fire resistance. Interactions between fumed silica and polysiloxanes also improve rheology, supporting better coating expansion and thermal insulation. However, PMVS-modified variants face some challenges in silica dispersion, which may affect spray application performance.
Overall, this scalable and innovative IFR coating technology offers significant potential for enhanced fire protection, particularly in urban infrastructure and high-risk environments where rapid response and thermal stability are critical.