Hexamethoxycyclotriphosphazene as a flame retardant for polyurethane foams

Polyurethane (PU) foams were protected by phosphorous and nitrogen-based molecular flame retardant hexamethoxycyclotriphosphazene c-[N = P(OMe)(2)](3) (HMCPT). This compound was synthesized, analyzed, and investigated with respect to its thermal behavior, compatibility, and efficiency as a flame retardant (FR) for PU foams. The decomposition of HMCPT starts at 186 degrees C in air and under argon, as indicated by TG/DSC measurements. It was possible to introduce 5 per hundred parts polyol (phpp) of HMCPT into the PU foams. The mechanical and morphological characteristics of the protected foams-compression load deflection, tenacity, tensile elongation, air perviousness, and raw density-were investigated indicating that the FR has an impact on all of these properties. The flame retardancy was evaluated with the FM VSS 302 test, where an self-extinguishing classification was reached with 5 phpp of HMCPT. Cone calorimeter measurements provide evidence for a flame poisoning mechanism. Copyright (c) 2013 John Wiley & Sons, Ltd.