Research On The Preparation And Properties Of Organic Electrical Modifier And Polyethylene Composite Materials

Polyolefin nano composite materials have become a hot research topic in the field of electrical insulation due to its excellent dielectric properties, and have made great progress. However, due to nano particles in the composite material is easy to agglomeration. Therefore, to prepare the polyolefin nano composite material with good dispersion and stability is still very difficult. Based on this, in order to overcome the agglomeration phenomenon in polyolefin nano composites, using organic electrical modifier to prepare polyethylene composite was studied in this paper. This work can lay the foundation for preparation of polyolefin composites with high dielectric properties in industrial production.This paper studies the synthesis of acetophenone derivatives. Using Friedel-Crafts reaction studies the synthesis conditions of acetophenone derivatives. The results show that:the optimum conditions for the synthesis of methyl acetophenone, molar ratio of acetic anhydride and toluene is1:3, reaction temperature is60℃, reaction time is3h. The optimal synthesis conditions for amyl acetophenone, molar ratio of acetic anhydride and n-amyl benzene is1:2, the reaction temperature is60℃, reaction time is4h. The optimal synthesis conditions for dodecyl acetophenone, molar ratio of acetic anhydride and dodecyl benzene is1:2, reaction temperature is70℃, reaction time is4h.This paper uses acetophenone derivatives and polyethylene to prepare composites by melt blending method. Through the volume resistivity, breakdown field strength, space charge analysis and the mechanical properties test, study the impact of the length of carbon chain and content of acetophenone derivatives on the properties of composite material. The results show that:With the length of carbon chain increasing, the volume resistivity and breakdown strength of the composite material was gradually increased. And also the effect of space charge suppression was enhanced. When adding2wt%dodecyl acetophenone in the polyethylene, the breakdown field strength is36.2%higher than that without added. And volume resistivity is10times higher than that without added. And the additions of2wt%dodecyl acetophenone can effectively suppress the space charge in the composites. The largest charge density in composites is decreased to about1.8C/m3. The electrical and mechanical properties of composite materials have been greatly improved.This paper also uses conductive polyaniline and polyethylene to prepare conductive polyaniline/polyethylene composites by melt blending method. The effects of different amounts of conductive polyaniline on electrical and mechanical properties of composite materials were investigated. The results show that:when the content of conductive polyaniline is lwt%, the composite material has good electrical properties. The volume resistivity is7.16×1014Ω·m and the breakdown field strength of the composite material is28.8kV/mm. It also can effectively suppress the accumulation of space charge in the composite material. In this case, the maximum charge density decreased to about2.2C/m3. It has little effect on the mechanical properties of the composites.