Pyrolysis characteristics and reaction mechanism of intumescent fire-retardant coating with thermogravimetry/Fourier transform infrared analysis

A research of intumescent fire-retardant coating (IFRC) pyrolysis characteristics and reaction mechanism was conducted by thermogravimetric analysis coupled with Fourier transform infrared spectrometry analysis at various heating rates. The results demonstrate that the pyrolysis process of IFRC could be separated into two stages. In stage I, which occurs within the temperature range of 300-800 K, there is a mass loss of 8.5%. The main gases released during this stage are NH3 and CH4. Moving on to stage II, which takes place within the temperature range of 800-1200 K, there is a significant mass loss of 42.9%. The main gases released during this stage are CO2 and H2O. Through the use of FTIR spectra, the production amount of main four components ranked as follows: CO2 > H2O > CH4 > NH3. Especially, the reaction expressions were further speculated and proposed. Subsequently, the two aforementioned stages were utilized based on both model-free and model-fitting methods to ascertain the possible reaction mechanism.