Electrical breakdown properties of blend polymers with low density polyethylene and polypropylene

In order to improve the breakdown properties of low density polyethylene (LDPE), the electrical properties of blend polymers of LDPE and Polypropylene (random copolymer of propylene and ethylene: R-EP) have been investigated at 30/spl deg/C, 60/spl deg/C and 90/spl deg/C. In the case of LDPE with 0.917 g/cm/sup 3/ and R-EP with 0.897 g/cm/sup 3/, the specimen with a higher R-EP content had a higher impulse breakdown strength at 90/spl deg/C than the specimen with a lower R-EP content, but there was no clear difference at 30/spl deg/C and 60/spl deg/C. However, in the case of LDPE with 0.924 g/cm/sup 3/ and the same R-EP, any improvement was not recognized for both impulse and dc breakdown strength of blend polymers throughout the temperature range from 30/spl deg/C to 90/spl deg/C. The increase in impulse breakdown strength may be related with the striated structure of specimen observed with the polarizing microscope.