Electric Charge Accumulation in Polar and Non-Polar Polymers under Electron Beam Irradiation

Abstract

The electric charge accumulation in the dielectric insulation materials under an electron beam irradiation (40 keV and 60 keV) was measured by using the pressure wave propagation (PWP) method. These insulation materials were polar polymeric films such as polycarbonate (PC), polyethylene-naphthalate (PEN), polyimide (PI) and polyethylene-terephthalate (PET), and non-polar polymeric films such as polystyrene (PS), polypropylene (PP), polyethylene (PE) and polytetra-fluoroethylene (PTFE).The PE and PTFE (non-polar polymers) showed the properties of large amount of electric charge accumulation more than 50 C/m 3 and took the time of arrival to saturation of charge accumulation over 80 minutes. On the other hand, it was found the peculiar effect that the charge accumulatuin in PTFE did not observe for the period of 20 minutes after starting electron beam irradiation, as shown Fig. 1 (PTFE). After the period of 20 minutes, the irradiated electric charge was gardually accumulated in PTFE.The PC, PEN, PI and PET (polar polymers) showed properties that smaller amount of charge accumulation about -6 to -14C/m 3 were saturated within the short time about 1.0 minutes after starting beam irradiation as shown Fig. 1 (PC, PI). The PP and PS (non-polar polymer) showed the properties of middle amount of charge accumulation about 20 C/m 3 and took the middle saturation time about 1 to 20 minutes. The PC, PEN, PI and PET (polar polymers) have the benzene ring in principal chain, and have the functional groups of carbonyl group, ester bond, ketone group. These functional groups possess the electrical dipole moment field for trapping an excess electron carrier by irradiation.The PE and PTFE (non-polar polymers) have a carbon-carbon principal chain. And the hydrogen atom was attached to a side chain of PE, the fluorine atom was attached to a side chain of PTFE. There is basically not a trapp site for the excess electron carrier by electron beam irradiation, because these polymers are not a functional group.This paper summarizes the relationship between the properties of irradiated electron charge accumulation and chemical structural formula. Futher more, this paper compares between the electro static potential distribution with negative charged polymer and its chemical structural formula.

Space charges remaining in polymers after electron beam irradiation and the role of conductivity in their decay profiles

“…Although the ionization‐induced electrons and holes would not be observed experimentally because their numbers should be the same, the backscattered electrons can be observed by the pulsed electroacoustic (PEA) method. It has been shown recently that the clarification of the relation between the insulating property and space charge distribution was difficult using electron injection into polymers . In that work , electrons were injected with an energy of 40 or 60 keV into sample sheets with thicknesses >100 μ m. We expected that a clear correlation could be found if the projected range was longer than the sample thickness .…”

“…It has been shown recently that the clarification of the relation between the insulating property and space charge distribution was difficult using electron injection into polymers . In that work , electrons were injected with an energy of 40 or 60 keV into sample sheets with thicknesses >100 μ m. We expected that a clear correlation could be found if the projected range was longer than the sample thickness . From this viewpoint, in our research, the acceleration energy was set at 200 keV, aiming at passing most injected electrons through the sample, leaving backscattered electrons behind with a relatively uniform distribution.…”

“…It has been shown recently that the clarification of the relation between the insulating property and space charge distribution was difficult using electron injection into polymers [11]. In that work [11], electrons were injected with an energy of 40 or 60 keV into sample sheets with thicknesses >100 μm. We expected that a clear correlation could be found if the projected range was longer than the sample thickness [12,13].…”

Space charge accumulation characteristics in fluorinated insulating material under dc high stress

“…One effective method for evaluating the internally stored charge of irradiated polymeric material is space charge distribution measuring, and there are studies [4][5][6] in which charge distributions accumulated during electron beam irradiation and after electron beam irradiation were measured. However, there are few studies 7 in which changes to insulation properties caused by electron beam irradiation were evaluated on the basis of space charge distribution.…”

Electro-adhesive gripper component selection for pick and place of commonly used materials

“…Polycarbonate is a polar polymer (Nagasawa, Honjoh, Takada, Miyake, & Tanaka, 2010) which is widely used in many industrial applications and also on 48 products which are part of our daily life. It is similar to other polar materials showed a small amount of charge accumulation about 5 to 20C/m3 and long saturation time about 1 to 20 minutes (Nagasawa, Honjoh, Takada, Miyake, & Tanaka, 2010) Polyethylene unlike Polycarbonate is a non-polar polymer (Nagasawa, Honjoh, Takada, Miyake, & Tanaka, 2010) (Juan P. Diaz Tellez, 2011) Different experiments were conducted by (Juan P. Diaz Tellez, 2011) the results represent that the adhesion force generated is dependent on the configuration of the electrode. The experimental results were limited to 4KV, as the materials were not able to handle very high voltages due to break down of the dielectric between the electrodes and the substrate thus Force…”