Synergistic enhancement of arc ablation resistance and mechanical properties of epoxy resin insulation

Arc ablation is one of the important inducements leading to the surface insulation failure of epoxy resin (EP) break insulation in a HVDC circuit breaker. As a promising method to enhance the arc ablation resistance of EP insulation, the use of heat-conducting nano-fillers has always been confronted with the contradiction between the enhancement of thermal properties and that of mechanical strength. Up to now, the ablation characteristics of EP nanocomposite under short-time partial arc ablation is still poorly understood, and the synergistical enhancement of arc ablation resistance and mechanical strength of EP insulation is not realized as yet. Focused on these uncharted areas, in this work, we prepared a novel EP nanocomposite by blending method using dopamine-modified h-BN flakes and rigid α-Al ₂ O ₃ microsphere as binary modifiers. The results indicate that, though the arc ablation resistance of EP insulation can be improved to some extent after introducing functionalized h-BN, however, the tensile strength decreases significantly. In comparison, the h-BN&α-Al ₂ O ₃ binary nanofillers may not only improve the apparent activation energy of EP insulation in thermal decomposition, but also regulate the interfacial interaction between particle swarms and EP matrix. This is beneficial to relieve the partial carbonization on the insulation surface thereby improving the toughness of the composite, which provides a feasible method to synergistically enhance the multiple properties of EP insulation.