Simultaneous Space Charge and Current Density Assessment in Additive-free LDPE under HVDC Condition

This paper presents the investigation into the electrical conduction properties of LDPE with electrode materials effect. Space charge and current measurement were monitored at two different applied electric fields. It was achieved using the Pulsed Electro-acoustic (PEA) technique on a newly constructed system, which is capable of quantifying space charge and current simultaneously in a planar sample. Tests were carried out with additive-free Low Density Polyethylene (LDPE) films under dc electric field at 30°C in a temperature-controlled environment. Aluminum (Al) and Semicon (Sc) were used for the electrode materials. The homocharges observed is alleged to be initiated from charge injection across the electrode/LDPE interfaces; this is ascribed to Schottky injection. Here, heterocharges spotted are developed when one of the electrodes partly blocks the extraction of charges injected by the other. The amount of charges injected into the bulk depends on the barrier height between the electrode/ LDPE interface, when the same material is exposed to different polarities, the barrier height also differ, therefore a contrasting feature of charges was exhibited