The influence of oxygen on thermal decomposition characteristics of epoxy resins cured by anhydride

Anhydride cured epoxy resins are always used as pivotal solid insulation medium in many electrical equipment, which will decompose due to the high temperature caused by partial discharge and the presence of oxygen will aggravate this process. In order to explore the influence of oxygen on the thermal decomposition characteristics of epoxy resin cured by anhydride, simulation models are established in this paper. The ReaxFF force field is used to simulate the pyrolysis process of epoxy resin and the changes in production of small molecular gases (such as CO2, H2O, CO and CH2O), and C2, C3 are discussed. The results show that the oxygen will affect the main chain of the epoxy resin by introducing a carbon-oxygen double bond to the tertiary carbon atom attached to oxygen atom. Meanwhile, with the presence of oxygen, all the products' initial generation time will be earlier, the amount of CO2 will increase, the amount of H2O will go up dramatically while that of CH2O remain basically unchanged, the types and quantities of C2 and C3 products increase obviously, mainly reflected in the oxygenated products. •Oxygen will bring forward the initial fracture of epoxy main chain.•Presence of oxygen advance the initial generation time of gas products.•Presence of oxygen increases the production of CO2 and H2O.•Types and quantities of oxygenated C2 and C3 products increase obviously.