Fire performance of piperazine phytate modified rigid polyurethane foam composites

Using phytic acid (PA) and piperazine (Pi) as raw materials, piperazine phytate (PA-Pi) was fabricated by simple ionic reaction. Furthermore, A series of rigid polyurethane foam/piperazine phytate (RPUF/PA-Pi) composites were prepared by one-step water-blown technology. Thermogravimetric (TG) results showed that the addition of PA-Pi improved the thermal stability of RPUF/PA-Pi composites at high temperature. At 700°C, RPUF/PA-Pi20 exhibited the highest carbon residue of 25.8 wt%. Cone calorimetry and smoke density tests suggested that PA-Pi could reduce the heat and smoke release during combustion process of the composites, thus reducing their fire hazard. Thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR) indicated that PA-Pi significantly inhibited the release of toxic gases (isocyanate compounds, aromatic compounds, CO and HCN) and flammable gases (hydrocarbons and esters) during the decomposition process of RPUF/PA-Pi composites, effectively improving fire performance of the composites. Scanning electron microscope (SEM), Raman and Fourier transform infrared spectroscopy (FTIR) were used to characterize the carbon residue of RPUF/PA-Pi composites. The results showed that PA-Pi could promote the formation of dense carbon layer of composites and effectively prevented heat and mass transfer in the combustion process.