Evaluation of electrical conductivity models for conductive polymer composites

Abstract

ABSTRACT:The electrical conductivity of polymeric materials can be increased by the addition of carbon fillers, such as carbon fibers and graphite. The resulting composites could be used in applications such as interference shielding and electrostatic dissipation. Electrical conductivity models are often proposed to predict the conductivity behavior of these materials in order to achieve more efficient material design that could reduce costly experimental work. The electrical conductivity of carbon-filled polymers was studied by adding four single fillers to nylon 6,6 and polycarbonate in increasing concentrations. The fillers used in this project include chopped and milled forms of polyacrylonitrile (PAN) carbon fiber, Thermocarb TM Specialty Graphite, and Ni-coated PAN carbon fiber. Material was extruded and injection-molded into test specimens, and then the electrical conductivity was measured. Data analysis included a comparison of the results to existing conductivity models. The results show that the model proposed by Mamunya, which takes into account the filler aspect ratio and the surface energy of the filler and polymer, most closely matched the conductivity data. This information will then be used in the development of improved conductivity models.

Electrical Conductivity Modeling of Polypropylene Composites Filled with Carbon Black and Acetylene Black

“…It takes into account the parameters previously neglected by other researchers. It gives a good agreement in the case of polymer composites filled with carbon black beyond the percolation threshold [14,15,[17][18][19][20][21][22]. Mamunya model cannot be used for filler concentrations lower than those of the percolation threshold and the term ((x − 2, 61)/27, 39) becomes negative in this area.…”

“…Several existing models were tested to find those that best describe the behavior of the composites studied. Among the models tested, that of Mamunya [13][14][15] seems to be more appropriate. It takes into account the parameters previously neglected by other researchers.…”

“…This is explained by the fact that Mamunya model was designed primarily to predict the behavior of polymers filled with carbon black beyond the percolation threshold [14,15,[17][18][19][20][21][22].…”

“…Among the models that predict the conductivity of the materials according to the interactions between the polymer and the filler, particularly those involving the surface tension and surface energy components are those proposed by Mamunya et al [13,14] and Clingerman et al [15].…”

Behavior of Conductive Particle Networks in Polymer Melts under Deformation

“…As the final morphology of the composites is usually formed during melt processing, it is important to understand the behavior of the particle networks under defined deformation in the molten state. The electrical properties of the composites with conductive fillers can be described by percolation theory and its numerous modifications [1,2]. It says that the conductivity increases steeply at a critical filler concentration called percolation threshold.…”