Kinetics of Thermal Decomposition of Polymethylmethacrylate in a Carbon Dioxide Environment

A thermogravimetric analysis of the thermal decomposition of polymethylmethacrylate (PMMA) in a carbon dioxide flow is carried out. The kinetic constants of the process are determined. The heating rate of the sample varies over in wide range and amounts to 2, 5, 8, 20, 35, and 50 K/min. The values of the kinetic constants of PMMA decomposition are determined using the isoconversional method. For the degree of conversion of the substance ranging from 10 to 90%, the values of activation energy for the thermal decomposition of PMMA vary in the range from 213.5 to 194.3 kJ/mol, and the values of the preexponential coefficient change in the range from 1.62 × 10¹⁶ to 6.85 × 10¹² 1/s. The average activation energy for the thermal decomposition of PMMA in a carbon dioxide flow is 206 kJ/mol.