Research On The Electrical Property Of Ac-SEBS/LDPE Composites

Polyethylene(PE)is used in electrical equipment insulation widely,which can improve the insulation performance of PE by adding additives.As a voltage stabilizer,acetophenone can improve the electrical properties of the material effectively.But acetophenone is a small molecule,which can be precipitated out of the matrix in long working conditions,affecting the long working performance of the materials.In order to inhibit the migration of acetophenone in PE,the acetylation reaction was made in the molecular chain of styrene-ethyl-butadiene-styrene(SEBS)to prepare the acetylated SEBS(Ac-SEBS)containing phenyl ketone groups.The structure of Ac-SEBS was characterized by Fourier infrared spectroscopy,and its PS segment was proved to be produced.Ac-SEBS of different grafting rates were prepared by controlling the addition of acetyl chloride in acetylation,and the accurate graft rate was characterized by MRI.The Ac-SEBS/LDPE composites with different mass fractions and different grafting rates were prepared by mixing Ac-SEBS with LDPE,and the crystallinity changes were analyzed through DSC.And then break down the test piece,the results show that: As the addition of Ac-SEBS increased,the dc breakdown field of the complex was first promoted and then decreased,with the highest content of 2%,which was 17.2% higher than that of pure LDPE.The communication breakdown field of complex was decreasing,at 1%.With the increase of Ac-SEBS grafting,the intensity of dc and Ac breakdown of the complex was first raised.With different grafting rate of Ac-SEBS/LDPE composites electric spark test of branches,the results show that voltage electric branches of the tree with the increasing of grafting rate and at first and lowered later highest when compared to the pure LDPE,increased by 30.05%,compared with SEBS/LDPE composites increased by 14.73%.The growth experiments of the Ac-SEBS/LDPE complexes and the pure LDPE were carried out,and the results showed that the adding Ac-SEBS could inhibit the growth of the electric branches.Measured with different mass fraction and different grafting rate of AcSEBS/LDPE composite dielectric constant and loss factor,dielectric constant and loss factor are as the increase of mass fraction or grafting rate,and were higher than pure LDPE.The adding Ac-SEBS can effectively inhibit the space charge.