Control of Filler Distribution in Polymer Composites

A fabrication method for polymer composites filled with particles or short-fibers was newly developed. The electrical conductivity of samples was investigated. Gradient polymer composites were prepared from epoxy resin and fillers by applying centrifugal force with a centrifuge machine. The gradient distributions of filler contents were varied by changing the filler shape and the rotation speed of the centrifuge machine. The majority of fibers aligned in the plane perpendicular to the direction of centrifugal force. The electrical conductivity of the polymer composites of epoxy resin filled with carbon-fibers or metal particles was measured. The electrical conductivity of epoxy resin filled with carbon-fibers, in the direction where centrifugal force was loaded, was almost constant. The value perpendicular to the centrifugal force direction was found to be correlated with the volume content of fillers. The electrical conductivity of epoxy resin filled with metal particles was also correlated with the volume fraction of particles. It was found that the electrical conductivity measurements can be used to evaluate the filler distribution of polymer composites.