The effects of γ-ray on charging behaviour using polyimide

Abstract

Insulation material is a key component of electrical equipment in satellites; its electrical properties determine the reliability and lifetime of the whole satellite. High-energy radioactive rays in space affect the molecular structure of the polymeric insulating materials. Under the action of plasma, high energy particles, along with the magnetic fields experienced in orbits, electric charges get injected into and trapped by the insulating material creating distortions in the electric field and even electrostatic discharges. Polyimides have been widely used for insulation in spacecraft. Choosing Co-60 gamma ray with irradiation doses of 1 MGy and 5 MGy to simulate the radiation environment of space, we investigated the effect of radiation on charging behaviour. The thermal stimulated current (TSC) from a high electric field over a wide range of temperatures was measured from which the activation energy was calculated. These results for the two sources show that the percentage increase in total charge was 133.3% and 119.4%. The γ, β 3 , and α charge peaks of specimens after an irradiation dose of 1 MGy rose. In comparison, the β 2 peak of the 5 MGy-dosed specimens was enhanced. Also, there is almost no change in the γ, β 3 , and α peaks. To understand the mechanism behind the TSC changes, the resulting physicochemical characteristics of an irradiated specimen were observed employing various analyses of chemical characteristics (x-ray photoelectron spectroscopy, differential scanning calorimetry and x-ray diffraction). Compared with the non-dosed specimen, the relative content of C-N and the glass transition temperature of the 1 MGy sample decreased, and the crystallinity increased, thus increasing the γ and α peak intensities. Compared with the 1 MGy sample, only the glass transition temperature had risen, thereby enhancing the β peak intensity. With the foregoing, a theoretical base for the selection and modification of insulation materials for spacecraft is provided.

Self-Healing of Electrical Damage in Microphase-Separated Polyurethane Elastomers with Robust Dielectric Strength Utilizing Dynamic Hydrogen Bonding Networks

“…The thermal stimulation depolarization current (TSDC) method has been widely used to evaluate various relaxation behaviors and reveal its microparameters in solid dielectrics. , During the heating measurement process, the frozen charges in the material are excited to form depolarization current at different temperatures according to their different activation energy . However, since the measured TSDC curve is often coupled with multiple current peaks, it is necessary to define and analyze different relaxation behaviors by using reasonable peak fitting methods . Based on the DSC results (Figure S2), Peak 1 comes from the α relaxation process near the glass-transition temperature of PUs.…”

Study of a Mixed Conductive Layer Fabricated by Ion Implantation and Distribution Theory

“…A distribution model of carbon black particles in PDMS after ion implantation is also presented. More importantly, these methods can support the development of electrodes in other areas of dielectrics [ 33 , 34 , 35 ] and research [ 36 , 37 , 38 ]. This work has potential value for the design of new flexible electrodes and composite conductive functional materials.…”

Comparative study on microstructure, mechanical, and tribological property of gamma‐irradiated polytetrafluoroethylene, polyetheretherketone, and polyimide polymers

“…materials, [9][10][11][12][13][14][15][16] which can play the role of insulation protection, 9,10 seal, 13 and lubrication 16 in a nuclear reactor. The interaction of highenergy radiation particles with polymers may damage the structure of polymers, resulting in chain scission, crosslinking, formation of double bonds, and molecular emission.…”