Thermo-oxidative degradation behavior of poly(vinyl chloride) insulation for new and overloaded wires via TG-FTIR

When a poly(vinyl chloride) (PVC) wire experiences overload failure, the internal structure of the insulation changes to become overloaded insulation and the fire hazard changes. In this study, the thermo-oxidative degradation behavior of new and overloaded PVC insulation materials was analyzed using coupled thermogravimetric-Fourier transform infrared spectroscopy (TG-FTIR). The thermo-oxidative degradation results show that the first two stages of thermo-oxidative degradation of PVC insulation are important stages for measuring fire hazard. In addition, the onset temperature of thermo-oxidative degradation of overloaded PVC insulation was increased. The activation energies of the first two stages of the overloaded PVC insulation increased by 7.7% and 27.0%, respectively, compared to the new PVC insulation. And the reaction mechanism is changed. The FTIR results indicate that the increased amount of volatile organic compounds and CO2 generated during the pyrolysis of the overloaded PVC insulation may result in the generation of more heat and smoke during combustion, thus increasing the fire hazard.