The Effect Of Orientation On Electrically Conducting Polymer Composite Properties

Abstract

Conductive polymer matrix composites have been a focus of research for the past 30 years, due to applications such as electromagnetic shielding. The electrical resistance of these materials can be broken into three major categories: the intrinsic resistance of the filler and matrix, the particle‐particle contact resistance, and the tunneling resistance. Both the particle‐particle contact and tunneling resistance in nickel filled low density polyethylene (LDPE) composites can be reduced by the addition of an ultrathin polypyrrole (PPy) coating on the nickel surface. Coating the nickel particles with PPy leads to increases in conductivity as much as three order of magnitude at concentrations well above the percolation threshold without significantly changing the mechanical properties. We believe at concentrations above the critical region PPy forms “molecular wires” reducing the loss of conductivity associated with the uniaxial orientation of the polymer matrix.

Electrical Conductivity of Polymer Composites Filled with Carbon Black

“…This is the case when CB filler content is lower than 30 wt% in HDPE. [30][31][32][33]35) However, Ketjen Black could not be filled to 55 wt% in HDPE this time. So the L of the composite composed of Ketjen Black was high than 1 cm.…”

“…Until now, the resistivity of composites consisting of a polymer and CB has been larger than 1 cm. [30][31][32][33] It is desirable to develop composites with a low L and a high H. We decided that the optimum L of the composite is less than 0.2 cm. We aimed at the highest H possible with no NTC effect after polymer melting.…”

Electrical Conductivity of Polymer Composites Filled with Metal

“…Prior to this study, L of composites consisting of polymer and carbon black (CB) was higher than 1 cm. [30][31][32][33][34][35] We have reported the relationships between the PTC properties and the type of resin, the resin's crystallinity, the resin's melt viscosity, the type of CB, and the particle size of CB. Having optimized the characteristics of the resin and CB, we achieved the lowest L (0.17 cm) and the highest H (930 cm).…”