Conductive polymer composites have been developed for electrostatic discharge and electromagnetic interference shielding. Loadings of >10% conductive fillers are typically required, but such loading levels result in high melt viscosity, poor appearance, contamination by sloughed off fillers and high material cost. We have found that small amounts of graphene nanoplatelets, 0.06 wt%, if located at the interfaces in a cocontinuous polymer blend, can percolate resulting in useful conductive composites. We will show how wetting properties as well as the kinetics of graphene movement during melt mixing can help to explain graphene jamming in the interfaces.
Chris Macosko is Director of the Industrial Partnership for Research in Interfacial and Materials Engineering and Professor of Chemical Engineering and Materials Science at the University of Minnesota and a member of the National Academy of Engineering. He received his B.S. from Carnegie Mellon, M.Sc. from Imperial College, London and Ph.D. from Princeton. He has advised over 100 M.S. and Ph.D. students and postdoctoral researchers with whom he has published over 500 papers in rheology and polymer processing. This research has been recognized with numerous awards including the Bingham medal of the Society of Rheology and election to the National Academy of Engineers. He co-founded Rheometric Scientific, now part of TA Instruments, which is a leading producer of rheological instruments. His rheology textbook "Rheology: Principles, Measurements, and Applications” (Wiley, 1994) is widely used.