Thermal degradation of poly(phenylene sulfide ether) (PPSE) was investigated by using thermogravimetry (TG) under air and nitrogen atmosphere. It was found that the existence of oxygen depressed the thermal stability of PPSE and changed the mechanism of thermal degradation. The influences of molecular weight and heating rate on the decomposition of PPSE were also investigated under N-2 atmosphere. The results showed that the thermal stability of PPSE was excellent and can be further enhanced by increasing molecular weight. A simple kinetic model concerning two parallel reactions in overall temperature range was proposed to describe the thermal degradation process of PPSE in nitrogen. Kinetic analysis of the dynamic TG curves for PPSE was carried Out by using Kissinger, Flynn-Wall-Ozawa, and Coats-Redfem methods. The kinetics of PPSE degradation displayed that the two parallel reactions were in accordance with the first-order equation. The kinetic model was further validated by comparing the experimental and calculated results. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 911-918, 2009