Boron Nitride Nanotube Novel Thermal Management Materials Technologies for High Power Naval Systems

Increased performance requirements of high-power or high-frequency electronics require novel thermal management materials. Boron nitride nanotubes (BNNTs) enhance performance of polymer-based electrically-insulating thermal interface materials (TIMs). This work will incorporate BNNTs into common micro-particle polymer composites to increase thermal transport between particles. Thermal impedance within TIMs is dominated by resistivity of the polymer which holds the thermally-conductive particles together in the matrix. Typically, inter-particulate space is 20% of interfaces’ volume. A multi-scale, bottoms-up approach to fabricating the filler material is expected to increase the thermal conductivity of many TIMs to above 10 W/m·K. TIMs based on epoxy, cyanoacrylate, silicone, silicone oil, nylon multipolymer thermoplastic, and polytetrafluoroethylene matrices will be explored. Preliminary in-house work already dramatically increased thermal conductivity to nearly 6 W/m·K in thermoplastics doped with BNNTs, implying an increase in inter-particle conductivity of ~20X. The TIMs produced in this study will be characterized for in- and through-plane thermal conductivity, and filler material development will be aided by scanning electron microscope imaging and surface area analysis of the densified powders to determine optimal ratios of components. The TIMs fabricated will be applicable within components, and as adhesives, pastes, top-side coatings, substrates, underfills, gap fillers, gap pads, and laminates.