Measuring thermal conductivity enhancement of polymer composites: Application to embedded electronics thermal design

The effect of volume fraction and type of conductive filler on the thermal conductivity enhancement of polymer composites is determined from a simplified experimental technique using both specimen measurements and numerical simulations. Two conductive fillers, boron nitride powder and fine-mesh aluminum fibers, are blended with two different polymers in volume percentages of up to 30 percent. The volume fraction and the particle distribution of the filler are found to be more critical than polymer selection for thermal conductivity enhancement. Inferences into the filler dispersion of the polymer composites is made by using analogies from thermal resistance networks. Using numerical simulations of an embedded electronic artifact, it is also shown that embedding heat-generating electronics within a thermally conductive polymer composite can significantly enhance its transient and steady-state thermal performance.