Tensile modulus modeling of carbon black/polycarbonate, carbon nanotube/polycarbonate, and exfoliated graphite nanoplatelet/polycarbonate composites

• Published in: Journal of applied polymer science Vol. 124; no. 3; pp. 2269 - 2277
• Main Authors: Via, Michael D., King, Julia A., Keith, Jason M., Miskioglu, Ibrahim, Cieslinski, Mark J., Anderson, Jonathan J., Bogucki, Gregg R.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05.05.2012; Wiley; Wiley Subscription Services, Inc
• Subjects: Applied sciences; carbon black; carbon nanotube; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Materials science; nanocomposites; polycarbonates; Polymer industry, paints, wood; Polymers; Technology of polymers; tension; carbon nanotube; tension; Electrical conductivity; Carbon black; Electrical properties; Carbon nanotubes; Dispersion reinforced material; Experimental study; Modeling; nanocomposites; Composite material; Multiwalled nanotube; Concentration effect; Graphite; Injection molding; Extrusion; Percolation; Nanocomposite; Polycarbonate; polycarbonates
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.35276

Conductive fillers are often added to thermoplastic polymers to increase the resulting composite's electrical conductivity (EC) which would enable them to be used in electrostatic dissipative and semiconductive applications. The resulting composite also exhibits increased tensile modulus. The filler aspect ratio plays an important role in modeling composite EC, and tensile modulus. It is difficult to measure the filler aspect ratio after the manufacturing process (often extrusion followed by injection molding) in the composite, especially when nanomaterials are used. The EC percolation threshold is a function of the filler aspect ratio; hence, knowledge of this percolation threshold provides a means to extract the filler aspect ratio. In this study, the percolation threshold of the composite was determined from EC measurements and modeling, which in turn was used to determine the filler aspect ratio for tensile modulus modeling. Per the authors' knowledge, this approach has not been previously reported in the open literature. The fillers; carbon black (CB: 2–10 wt %), multiwalled carbon nanotubes (CNT: 0.5–8 wt %), or exfoliated graphite nanoplatelets (GNP: 2–12 wt %); were added to polycarbonate (PC) and the resulting composites were tested for EC and tensile modulus. With the filler aspect ratio determined from EC values for CNT/PC and GNP/PC composites, the three‐dimensional randomly oriented fiber Halpin‐Tsai model accurately estimates the tensile modulus for the CNT/PC composites and the Nielsen model predicts the tensile modulus well for the CB/PC and GNP/PC composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012