Physical and Spectrometric Analysis of Electron-Damaged LDPE

Low-density polyethylene (LDPE) is a nonpolar polymer commonly used as an insulating material. Although its applications in the spacecraft industry are limited, LDPE is widely utilized as a model system to study electron transport through disordered insulating materials under simulated space weather conditions. The charge transport models developed using this system may then be extended to more commonly used spacecraft materials such as polyimides. Several proposed charge transport models share high complexity and many free fitting parameters. For better estimation of initial values of these free parameters, the correlation between charge transport and its chemical origins should be made. Whenever possible, experimental measurements should be used as initial values for each of the free fitting parameters to improve model accuracy. In this paper, we studied alterations of the chemical properties of LDPE after irradiation by high-energy (100 keV) electrons using Fourier transform infrared spectroscopy (FTIR) and bulk conductivity measurements. Moreover, we utilized a quadrupole mass spectrometer (QMS) to identify the ablated species released from the solid during irradiation. These measurements offer insight into the structural and chemical damages of the material. Results of the performed analysis are correlated with the underlying chemical changes that occur in LDPE during irradiation.