Study of the percolation phenomenon of high field volt-ampere characteristic in the composite of low-density polyethylene/nano-SiOx

The composite of low-density polyethylene (LDPE)/nano SiO_x was prepared by the method of double-solution mixture, and its high field volt-ampere characteristic (HFVAC) was studied The HFVAC of the composite significantly differs to that of pure LDPE. More interesting is that, at the contents of 0.5%-3% of nano SiOx, the percolation phenomena exits in the HFVAC of the composite. At the same time, morphology of the composite was investigated with transmission electron microscope (TEM) and dynamic mechanical analyser (DMA), respectively. It is shown by DMA that the glass transition temperature (T_g), the mechanical loss (tanδ), and the storage modulus E´ of the composite are not linear with the contents of nano SiO_x. At last, on the basis of morphology of the composite, the mechanism of the percolation phenomena of HFVAC was discussed.