The Pyrolysis Behavior of Modified Poly-m-phenylene Terephthalamide by 4, 4'-diamino Diphenyl Sulfone

The modified Poly-m-phenylene terephthalamide (co-PMTA3) was prepared by polycondensa-tion of m-Phenylenediamine, 4, 4'-diamino diphenyl sulfone and terephthaloyl dichloride with a mole ratio of 3:1:4 in N, N'-dimethylacetamide at low temperature. co-PMTA3 was soluble and expected to transform into fiber. The heat-resistance and thermal stability of co-PMTA3 were investigated by differential scanning calorimetry and thermogravi-metric analysis, respectively. The results indicate that the co-PMTA3 possesses excellent heat-resistance and thermal stability with a glass transition temperature of 318.4 °C, initial thermal decomposition temperatures of 404.0 °C in air and 445.5 °C in nitrogen. In addition, the active energy (Ea) of the decomposition process in air atmosphere was estimated by Ozawa-Flynn-Wall method which was between 116.2 and 315.6 kJ/mol. The results indicate that the decomposition of co-PMTA3 air atmosphere is an overall reaction of multi elementary reactions.