G.D. Liang

Electrical properties of percolative polystyrene/carbon nanofiber composites

Polystyrene/carbon nanofiber nanocomposites (PS/CNF) were prepared by melt compounding. The dielectric and electrical conducting properties of the PS/CNF nanocomposites were investigated. The conductivity and dielectric constant of the polymer composites were significantly enhanced by adding CNF at a very low loading level of 1.7 vol%. The dielectric constant also increased in the same way as a result of percolation. Furthermore, the resistivity of the PS/1.7 vol% CNF nanocomposite was greatly dependent on temperature. A sharp increase in resistivity of PS/1.7 vol% CNF nanocomposite was observed at 60-150degC, being related to the mobility of PS macromolecular chains near the glass transition temperature.

Fabrication and electrical conducting behavior of carbon nanofiber reinforced high-density polyethylene/ polystyrene nanocomposites with low percolation threshold

Abstract Ternary high-density polyethylene/polystyrene/carbon nanofiber nano composites were fabricated by melt-compounding. The effect of melt compounding sequences on electrical conducting behavior of such composites was examined. Two compounding sequences were adopted in this study. Route I consisted of an initial melt mixing of HDPE and PS, followed by blending with CNFs. Route II involved an initial formation of the PS/CNF master batch, followed by blending with HDPE. The results showed that CNFs were dispersed in HDPE phase of Route I prepared HDPE/PS/CNF nanocomposites whilst they resided in PS phase of Route II formed nanocomposites. Electrical measurement showed that Route II prepared nanocomposites had a low percolation concentration of 1.1 vol% CNF.

Electrical Behavior of High Density Polyethylene/ZnO Nano-composites

Abstract High density polyethylene (HDPE)/ZnO composites containing a wide range of ZnO content (1-60 vol%) were prepared by melt compounding. ZnO powders with sizes of ~ 200 nm and ~ 2 μm were employed as reinforcing fillers. The effects of the size and filler particle content as well as annealing treatment on the dielectric and conducting properties of the HDPE/ZnO composites were examined. The results showed that the dielectric constant of HDPE/ZnO composites increased gradually with an increase of the ZnO content. The resistivity of HDPE/ZnO composites can be described satisfactorily by the interparticle distance of filled particles. This behavior is interpreted in terms of tunneling of the electrons through the insulating layer of polymer separating two neighboring ZnO fillers. The correlation between the structure and electrical property of the composites is discussed.