Thermal degradation study of rigid polyurethane foams containing tris(1-chloro-2-propyl)phosphate and modified aramid fiber

The rigid polyurethane foams (RPUF) were prepared using tris(1-chloro-2-propyl)phosphate(TCPP) and modified aramid fiber(MAF) as flame retardants. The thermal degradation behaviors of RPUF and flame retardant RPUF were investigated by thermogravimetric analysis/infrared spectrometry (TG-IR), gas chromatography-mass spectrometry (GC-MS). Char residue for PU composites at different temperatures was analyzed by fourier transform infrared spectra (FTIR). The TGA curves suggested that aramid fiber(AF) has good ability of char formation. In TG-IR measurement, simultaneously use of TCPP and MAF in the RPUF exhibited lower smoke and toxicant production and increased char residue compared to RPUF containing TCPP. Production of toxic gases such as hydrogen cyanide (HCN) was significantly decreased, nonflammable gases carbon dioxide (CO2) and water were increased. GC-MS illustrated that TCPP and MAF exerted barrier effect in the condensed phase and the quench effect in the gaseous phase. Based on these facts, a potential thermal degradation mechanism was primarily proposed.