Dielectric Properties Of Nano SiC And Plasma Treatment Nano Particles LDPE Composites

Nano-SiC/LDPE composites with different mass fractions（0.5wt%, 2wt%, 3wt%） were prepared by meltblending method. Dispersion character of nanoparticles has been identified by SEM, the result indicated that nanoparcticlesdispersed homogeneously in nano-SiC/LDPE composites. The space charge distribution character wereobtained by using pulse electro-acousitc method, the results show that the amount of injected charge density of eachmaterial with nano particle 0.5wt%, 2wt% and 3wt% loaded are much lower than LDPE material（1.49 C/m3）. Theamount of injected space charge and DC conductivity both reduce with the increasing of nano-SiC particle in nanocomposties.The nonlinear coefficient of current density-electric field（j-E） character fitting curves of 3wt% nano-SiC/LDPE is 2.6, which is much smaller than that of LDPE sample（4.3）. It could be deduced that the density of thetrap levels increased with additional of nano-SiC particles,which could hinder the transportation of carriers and themigration and accumulation of space charge. Thermal simulated current（TSC） was also employed to identify thetraps density directly. Results showed the trap density increased in LDPE nanocomposites material which is coincidentwith above discussion.In order to explore the influence of the nanocomposite dielectric interface elements on space chargeinhibition ability, nano SiC, MgO and SiO₂ particles processed by plasma were prepared. Nano-SiC/LDPE,nano-MgO/LDPE and nono-SiO₂/LDPE composites with mass fraction 1wt% were prepared by melt blending method.The results of X-ray photoelectron spectroscopy and pulsed electro acoustic experiment showed thatthe content of C-O bond of nano-SiC/LDPE processed by oxygen plasma and Si-O bond of nano-SiC/LDPE processed by water plasma increased 22% and 19.4% respectively, which lead to the phenomenon of nano-SiC reuniting so that space charge inhibition ability reduced too. The content of O-H bond of nano-MgO/LDPE processed by oxygen and water plasma incressted 14.8% and 15.96% respectively, which made the density of deep trap forming on the surface of nanopartticles and the repulsion between nanopartticles bigger so that nano particles dispersion becamed better and space charge inhibition ability was enhanced. The content of Si-O bond of SiO₂/LDPE nanocomposite processed by plasma increased slightly, and the space charge inhibition ability improve obviously.