Effects of Blend of Polypropylene Copolymer on Electrical Breakdown of Low Density Polyethylene

Abstract

In order to improve the breakdown properties of low density polyethylene (LDPE), the electrical properties of blend polymers of LDPE and random copolymer of ethylene and propylene (EP) have been investigated at 30°C, 60°C and 90°C. The specimen with a higher. EP content had a higher impulse breakdown strength at 90°C than the specimen with a lower EP content, but there was no obvious difference at 30°C and 60°C However, in the case of DC breakdown, any improvement was not recognized for blend polymers throughout the temperature range from 30°C to 90°C, The morphology of blends was studied by a polarizing microscope and X-ray diffraction, The influences of morphology on breakdown properties were discussed. The morphological change by introduction of EP into LDPE was demonstrated by the decrease in the size of a spherulite, the existence of EP in the inter-spherulitic boundary region and the enhancement of orientation. The improvement of impulse breakdown strength at 90°C was explained on the basis of morphological change.