Electrical properties of biodegradable polylactic acid film

Recently, much importance has been attached to the problem of environmental pollution by industrial waste products. Recently, biodegradable polymers have attracted interest in that they open the way to an unexplored processing method for the disposal of industrial wastes Polylactic acid (PLA) is the polymer material on which biodegradability research has been the most advanced. Making the most of this advantage, in the future, we plan to apply PLA as an insulating material, for example, in electric wires and cables. For this reason, we measured the basic electrical insulation characteristic of PLA, and the following results were obtained. The measurement results of volume resistivity, dielectric constant and dielectric loss tangent, at room temperature, were almost the same as those of crosslinked polyethylene (XLPE) currently used as the insulating material for cables and electric wire, respectively. The mean value of the impulse breakdown strength of PLA was about 1.3 times that of XLPE. Thus, the possibility of the insulation thickness reduction of electric wire and cable is demonstrated. Also, the space charge accumulation of the PLA and XLPE was measured. The value of the space charge accumulation of the PLL A is half of that of XLPE, when the DC voltage was applied for a short time.