Rheology of Bulk Molding Compounds

Bulk molding compound (BMC) 940, composed of graphite powder and thermoset resin, can not be tested through standard rheology equipment. To determine its surface slip properties, a tracer material that does not disturb the BMC natural properties needs to be discovered and manual compression test must be performed. Teflon was first chosen as a tracer due to its unreactive properties and, after several test, proved to work ideally. Numerous experiments were performed with Teflon as a tracer to determine is slip occurred, the intensity of slip, if slip was a function of height, if slip was a function of pressure, and how surface roughness affected slip. After analyzing the results, it was found that BMC 940 has almost perfect slip at the surface. When altering the height and pressure of the samples, it was concluded that slip is unaffected by either. Lastly, when placing the BMC sample on a stainless steel plate with vertical grooves and compressing, the horizontal slip had decreased but did not disappear while the vertical slip increased to become larger then perfect slip.