Preparation And Dielectric Properties Of Vinyloxyacetophenone Grafted XLPE Insulation Material

As an excellent insulation material,cross-linked polyethylene is widely used in power cables due to its good electrical and mechanical properties.Acetophenone is a by-product produced by the decomposition of cross-linking agents during peroxide cross-linking.A large number of studies have proved that the addition of acetophenone can improve the electrical resistance and breakdown performance of materials.However,due to the poor compatibility of acetophenone with PE,it is easy to migrate from the material.Therefore,by preparing a graftable voltage stabilizer,migration of the voltage stabilizer can be fundamentally suppressed.In this paper,by modifying the structure of acetophenone,a side chain containing a double bond group,namely vinyloxyacetophenone(VPE),is introduced at the para-position of acetophenone.Using DCP as a cross-linking agent,polyethylene cross-linking and acetophenone grafting were completed simultaneously.The grafts were characterized and tested for their electrical properties.It was confirmed through experiments that the one-step preparation of grafted XLPE can effectively inhibit the migration of acetophenone,but with the increase of the content of acetophenone,the gel content gradually decreased.Analysis of the thermal stability and grafting effect of the material after grafting acetophenone by thermal weight loss,the results show that a high grafting efficiency can be achieved by this process,and the acetophenone graft with a content of 0.6wt% is thermally stable The performance is better than XLPE,but when the acetophenone content is higher than 0.6wt%,the thermal stability decreases.By testing the AC and DC breakdown field strengths of the material at different temperatures,it was concluded that the grafted acetophenone grafts with different contents had different degrees of improvement compared to pure XLPE.At 30°C,the acetophenone graft with 0.8wt% content has the highest breakdown strength,and at high temperature,the acetophenone graft with 0.6wt% content has the highest breakdown strength.The ability of the XLPE material grafted with acetophenone to inhibit the dendrite was significantly better than that of XLPE using the electric tree observation platform.The space charge was studied at different temperatures,and the results show that grafted acetophenone can effectively inhibit the generation of space charge.Then the electrical current characteristics at room temperature in the range of 3 k V/mm to 30 k V/mm were measured.The experimental results show that the electrical current of the graft is significantly smaller than that of XLPE.