The thermal decomposition kinetics of the N,N'-bis(5,5-dimethyl-2-phospha-2-thio-1,3-di- oxan-2-yl) ethylene diamine (DPTDEDA) in N₂ were studied by TG-DTG techniques. The kinetic parameters, including the activation energy and frequency factor of the decomposition process for the title compound were calculated through the Kissinger and Flynn-Wall-Ozawa(FWO) method and the thermal decomposition mechanism of DPTDEDA was also studied with the Satava-Sestak method. The results show that the activation energy and pre-exponential factor are 137.37 kJ•mol^－1 and 1.45×1012 s^－1 with the Kissinger method and 139.83 kJ•mol^－1 with the Flynn-Wall-Ozawa method respectively. The thermal decomposition mechanism of DPTDEDA is phase boundary reaction and the kinetic equation can be expressed as G(α)＝1－(1－α)⁴, and the reaction order is n＝4.

Key words: N,N'-bis(5,5-dimethyl-2-phospha-2-thio-1,3-dioxan-2-yl)ethylene diamine, thermal decomposition kinetics, activation energy, mechanism