Space charge behavior in low-density polyethylene

Abstract

The space charge distribution in low-density polyethylene (LDPE) was measured with the pulsed electroacoustic (PEA) method. We used three types of LDPE: LDPE-L and LDPE-H were prepared by the high pressure process, and m-LDPE was polymerized with a metallocene catalyst. Space charge in LDPE strongly depended upon the electrode material. Semiconductive electrodes enhanced carrier injection into LDPE and, as a result, space charge. The density, polymerization process, applied field, temperature and so on also affected the space charge behavior. This space charge behavior was compared with the results of dc current measurements.

Effect of diffusion on space charge formation in dielectrics under steady-state DC conditions

“…In conclusion the results obtained using author's formulae are found to match well, qualitatively, with the experimental results published in the literature [19,20]. Due to page limit many other results are omitted.…”

“…2 & 3 there is remarkable qualitative matching with generally observed space charge and electric field profiles measured using Pulsed Electro-Acoustic method (PEA) [19,20]. Only that the sharp peaks near electrodes, Fig.…”

“…Fig. 8 shows hetero space charge profiles in a certain range of values for boundary charge, calculated using equation (19). Corresponding electric field profi les are shown in the Fig.…”

“…Referring to Fig. 6, homo space charge at different boundary conditions, calculated using equation (19), indicates that even with highest possible space charge at electrodes the charge penetration into the sample is limited to a few microns, that depends on internal volume resistivity, permittivity and diffusion constant of the charges. This depth of penetration is found to be almost independent of the thickness, as long as the physical properties remain same.…”

Effects of electrodes on space charge in low-density polyethylene

“…The space charge sometimes affects the breakdown of an insulating material because it enhances a local electric field [l]. However, space charge behaviors are complicated and they depend upon physical / chemical structures of an insulating material, impurities, additives, temperature, applied electric field and so on [2]. There are many obscure tbings such as types of charge carriers, origins of carrier traps, and effects of electrode on space charge [3].…”