We examine the percolation threshold for composites made by dispersing anisometric, single-crystal graphite flakes in either an epoxy resin or a polyurethane polymer matrix. Analysis is based on empirical and excluded-volume approaches and the results are compared with a similar treatment using literature data of carbon-fiber based composites. © 1996 The American Physical Society.

• Received 17 July 1995

DOI:https://doi.org/10.1103/PhysRevB.53.6209