Compatibility of eco-friendly insulating medium C6F12O and sealing material NBR

Abstract

The eco-friendly insulating medium C6F12O has good insulation properties, and it has the prospect to be used in medium and low voltage switchgear. The compatibility between C6F12O and the sealing material commonly used in gas-insulated equipment [nitrile butadiene rubber (NBR)] needs to be studied before C6F12O could be put into practical use. In this paper, the compatibility test between NBR and C6F12O is carried out. Scanning electron microscopy and x-ray photoelectron spectroscopy are used to detect the surface morphology and element changes in NBR before and after the test. At the same time, the interaction between C6F12O and NBR is simulated based on molecular dynamics, and the solubility parameters, diffusion coefficient, and radial distribution function are calculated. The test results show that the NBR surface is damaged by C6F12O for a long time and a large number of raised cracks and F elements appear on the NBR surface. At the same time, the calculation results show that the solubility parameter of SF6 and C6F12O is 18.730 and 14.267 (J/cm3)1/2, respectively. The diffusion coefficient of C6F12O in NBR (13.500 × 10−7 cm2/s) is higher than that of SF6 (10.333 × 10−7 cm2/s), which reveals that C6F12O is easier to diffuse in NBR. Both C6F12O/NBR and SF6/NBR have hydrogen bonding force, but the interaction between C6F12O and NBR is stronger than that of SF6. These results can provide theoretical and technical reference for the material selection and design of C6F12O gas insulated equipment.