高能电子辐照对双向拉伸聚丙烯薄膜的微观结构及介电性能影响

Exploring the change law of microstructure and dielectric properties of dielectric materials under irradiation environment has an important application value for the development of dielectric materials under irradiation environment. In this paper, biaxially oriented polypropylene (BOPP) films were irradiated under different high-energy electron beam (5MeV, 10MeV, 15MeV and 20MeV). The microstructure of BOPP was characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC), Fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Meanwhile, the dielectric properties of BOPP were obtained by broadband dielectric spectrometer and precision DC power supply. The results show that the main chain of BOPP was broken by high-energy electron irradiation, and oxygen containing functional groups (C-O) and carbonyl groups were generated. With the increase of electron beam energy, the number of molecules per unit volume in polar groups decreased, which reduced the dielectric constant. Moreover, BOPP underwent an oxidative cracking reaction after irradiation. The generation of a large number of conductive ions led to the increase of conductivity loss, which caused an increase in the dielectric loss, and the dissociation of increase of surface defects reduced the breakdown field internal structure and the strength. This paper not only explored the microstructure changes and dielectric properties of BOPP under high-energy electron irradiation, but also provided a research basis for the development of dielectric materials under irradiation environment.