Influence of the physical and chemical properties of particles on the thermal conductivity of polymer composite materials

The dependences between thermal conductivity and the maximum volume fraction of the filler in heat sink compound on the size, morphology, specific surface area, and particle porosity, as well as the contact angle with silicone, of various materials such as aluminum oxides, silicon, magnesium, aluminum and boron nitrides, silicon carbide, metals (aluminum, copper, nickel), and carbon materials (graphite and diamond) is presented. The quality of the produced heat sink compound is not governed by any single property listed, but rather by the combination of properties such as morphology and specific surface area (or porosity) of the particles. For each type of filler particle shape, an inversely proportional relationship exists between the specific surface area and the maximum volume fraction of the polymer. Specific aspects were discussed regarding the effect of the material's phase and chemical composition on the angle of wettability by polydimethylsiloxane.