High Field Electrical Conduction in the Nanocomposite of Low-density Polyethylene and Nano-SiOX

Molecular structure and morphology of a nanocomposite of low-density polyethylene (LDPE) and nano-SiOx were studied by dynamic mechanical analysis (DMA). The storage modulus (E/) and the glass transition temperature (Tg) of the nanocomposite are higher than those of pure LDPE and vary with nano-SiOx contents in U-shapes. High field electrical conduction in the nanocomposite was investigated in the range of 293K˜353K, which is consistent with a theory based on the conventional thermally activated ionic hopping conduction. The average hopping distance for the nanocomposite containing 1wt % nano-SiOx shifts from 4.3 to 4.7 nm as the temperature increases from 293K to 353K. Space charge distribution was taken to confirm ionic hopping conduction being the dominant one in the nanocompostie. It is interesting that the relationship between nano-SiOx content and DC conduction was similar to a percolation conduction existing in a composite of conductive particles (or semi conductive particles) and a polymer. At last, high field electrical conduction mechanism in the composite was discussed on the basis of microscopic structure of the nanocomposite.