Flame-retardant properties of sodium silicate/polyisocyanate organic–inorganic hybrid material

To improve the flame-retardant properties of polymer materials, an organic–inorganic hybrid material was obtained by various mixed ratios of sodium silicate solution and polyisocyanate. The chemical structure of materials was characterized by Fourier transform infrared spectroscopy, and the microstructures were observed by scanning electron microscope. The influence of various ratios of polyisocyanate and sodium silicate on the flame-retardant properties of hybrid materials was emphatically investigated. The results showed that Si–O and Si–O–Si bonds were introduced into the hybrid materials and the surfaces were rougher than that of rigid polyurethane. The hybrid materials had better flame-retardant properties than the rigid polyurethane with an obvious decrease in heat release rate, spread rate of fire, decomposition rate and increase in residue and LOI value. When the hybrid materials were burning, less carbon dioxide and carbon monoxide were produced. In addition, the TG curve showed that the mass of hybrid materials decreased more slowly than the mass of the rigid polyurethane. So the hybrid materials showed excellent flame-retardant properties.