The energy criterion for breaking chemical bonds in electrical breakdown process of polymers

The energy required for electrons to break chemical bonds is traditionally referred to as the bonding energy. On the basis of chemical structure theory and the characteristics of electrical breakdown in polymers, the present paper suggests that the bonding energy is inadequate to express the energy required for breaking chemical bonds of polymers in electrical breakdown processes. Based on a comprehensive analysis of the breakdown strength and morphology parameters measured with X-ray photoelectron spectrometry (XPS), small-angle X-ray scattering (SAXS) and X-ray wide angle diffraction (XWAD) techniques, the calculated energy required for breaking chemical bonds causing breakdown of polypropylene is about 8.2 eV, which is approximately equal to the band gap energy (E_g). Both the theoretical analysis and the experimental results in the present study show clearly that the band gap (E_g), instead of the bonding energy, should be considered as the energy criterion for breaking chemical bonds in electrical breakdown processes of polymers