Thermal stability of flexible polyurethane foams containing modified layered double hydroxides and zinc borate

Flexible polyurethane foams (FPUFs) have been modified to contain layered double hydroxides (LDHs) by dihydrogen phosphate (H2PO4-). The thermal stability of the prepared foams has been characterized using thermogravimetric analysis (TGA) at 5, 10, 20, 30, and 40 degrees C/min heating rates. The experimental data indicate that the temperature range for the two pyrolysis stages of FPUF is about 212-350 degrees C and 350-565 degrees C, respectively. Integral programmed decomposition temperature (IPDT) has been calculated according to the measured data, which was found that the IPDT of the modified FPUF was increased to 526 degrees C. Additionally, the thermal stability of FPUF composite has been also evaluated by the activation energy (E) on the basis of the pyrolysis kinetics of FPUF composites during thermal decomposition using Coats-Redfern integral method. These results manifest that the presence of intercalated LDHs enhances the thermal stability of FPUF.