Pyrolysis Characteristics and Reaction Mechanism of Cement Fiberboard with Thermogravimetry/Fourier Transform Infrared Analysis

In this study, thermogravimetric analysis (TGA) was coupled with Fourier-transform infrared (FTIR) spectroscopy to systematically investigate the pyrolysis characteristics and mechanisms of cement fiberboard across varying heating rates. Experimental findings demonstrated that the thermal degradation process occurs in four distinct phases. Overlapping decomposition peaks in DTG curves were successfully resolved using a double-Gaussian deconvolution algorithm. A comprehensive kinetic analysis was conducted by integrating model-free iso-conversional methods (Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose analysis) with a model-fitting technique (Coats–Redfern approximation) to determine the activation energies for each degradation stage. A subsequent FTIR spectroscopic analysis revealed that the evolution of gaseous products follows the sequence CO2 > H2O > CH4. The CO2 release was found to originate from multiple pathways, including the decomposition of organic components and high-temperature inorganic reactions. Notably, while the heating rate had a negligible impact on product speciation, it exhibited a statistically significant influence on CO2 emission intensities. Finally, mechanistic interpretations integrating Arrhenius parameters with time-resolved infrared spectral features were proposed for each thermal decomposition stage.