Study On Dielectric Properties Of LDPE Added Nano-SiC

With the rapid development of modern society, polymer materials, especiallypolymer materials due to its good electrical properties, is widely used in high voltageinsulation and electronic products. Doped with nonlinear conductivity inorganicadditives, polymer materials can inhibit the producing of the space charge as well as thedevelopment of electrical tree and improve the insulation performance of polymericmaterials, among which, adding nano inorganic additives to the low densitypolyethylene (LDPE) to prepare nanocomposites has become a hot topic of research athome and abroad.In this paper, We used coupling agents in the surface modification of nano-SiC,then the blending surface modified nano-SiC particles, unmodified nano-SiC particlesand LDPE are mixed in the molten state, prepared a variety of composite materials ofdifferent mass fractions, and conducted relational electrical performance test, thefollowing conclusions:①Respectively use the different coupling agent A-171and KH-560in surfacemodification of nano-SiC particles, use the twin-screw plasticizing machine torespectively mix the modified nano-SiC particles and unmodified nano-SiC particleswith LDPE in molten state, prepared from1%,3%,5%in three different mass fractioncontent of composite materials;②According to the observation and testing of the microstructure of the material byscanning electron microscopy (SEM) and differential thermal scanner (DS(C) on theprepared composite materials style that the prepared composite material is relativelycomplete, when the nano-SiC comes excessive, agglomeration is fairly severe, thusaffecting the crystal structure of the composites;③Use the pulse method of electro-acoustic to conducting the space chargeobservation experiment on varies material styles: polyethylene, adding nano particles toLDPE can improve the distribution of space charge, and has certain block function inthe electrode polarity charge injection; A-171SiC/LDPE space charge transfer anddissipation of the fastest, and tend to the positive polarity; KH-560SiC/LDPE inhibit theeffect of space charge, and has a negative affinity;④Prepared various materials styles dielectric performance testing: Addingnanoparticles can improve the relative permittivity of the composite materials. to change the microscopic structure of the polyethylene surface modification of nano-SiCparticles in LDPE, may lead to composite dielectric constant abnormal; the dielectricloss of the composites increased with the content of nano-additives and increased loss ismainly from the electronic displacement polarization and atomic displacementpolarization; with the content of the composite nano-additives increase its conductivitywill also rise;⑤Use the needle plate electrode to do the plus piezoelectric tree growthexperiments of the different composite material1%mass fraction content, and collectinternal partial discharge signal pattern and analysis the statistical parameters: ThePartial discharge behavior of LDPE, SiC/LDPE and KH-560SiC/LDPE andA-171SiC/LDPE composite material all have polarity bias, the first three electrical treeresistance performance order decline, A-171SiC/LDPE has the best resistance toelectrical tree performance.