Abstract
Abstract
Nano-sized hexagonal boron nitride (nano-hBN) was incorporated into an ethylene propylene diene monomer (EPDM)/micro-sized silicon carbide (micro-SiC) composite in order to prepare an electrical insulation material for high voltage direct current (HVDC). The surface of nano-hBN and micro-SiC was organized with 1,3-divinyl-1,1,3,3-tetramethyldisilazane, and the effects of nano-hBN content on HVDC and HVAC electrical breakdown strength, thermal conductivity and tensile characteristics were studied. EPDM/micro-SiC/nano-hBN composite was prepared by a two-roll mill in the weight ratio of EPDM : micro-SiC : nano-hBN = 100g : 25g : 0-30g. As nano-hBN content increased, thermal conductivity of EPDM/micro-SiC/nano-hBN composite increased, thereby effectively dissipating heat and preventing the thermal degradation of polymer chain. When 20g of nano-hBN particle was incorporated into EPDM(100g)/micro-SiC(25g) composite, HVDC breakdown strength and HVAC breakdown strength were maximum. (+)HVDC breakdown strength for the composite without nano-hBN was 87.3 kV/mm and that for the composite with nano-hBN(20 phr) was 95.4 kV/mm, which was 9.3% higher. (-)HVDC breakdown strength for the composite without nano-hBN was 89.3 kV/mm and that for the composite with nano-hBN(20 phr (parts per hundred epoxy resin)) was 98.2 kV/mm, which was 10.0% higher.