Advanced Materials for Electronics Insulation

Many researchers have attempted to use polymer-ceramic composites to improve the thermal and dielectric performance of polymer insulation for high voltage, high temperature electronics. However, using composite materials has been challenging due to manufacturing issues like incomplete mixing, inhomogeneous properties, and void formation. Here, NASA has developed a method of preparing and extruding polymer-ceramic composites that results in high-quality, flexible composite ribbons. To achieve this, pellets of a thermoplastic (e.g., polyphenylsulfone or PPSU) are coated with an additive then mixed with particles of a ceramic (e.g., boron nitride or BN) as shown in the image below. After mixing the coated polymer with the ceramic particles, the blended material was processed into ribbons or films by twin-screw extrusion. The resulting ribbons are highly flexible, well-mixed, and void free, enabled by the coated additive and by using a particle mixture of micronized BN and nanoparticles of hexagonal BN (hBN). The polymer-ceramic composite showed tunable dielectric and thermal properties depending on the exact processing method and composite makeup. Compared to the base polymer material, the composite ribbons showed comparable or improved dielectric properties and enhanced thermal conductivity, allowing the composite to be used as electrical insulation in high-power, high-temperature conditions. The related patent is now available to license. Please note that NASA does not manufacturer products itself for commercial sale. Electrical insulation materials for wires and other high-power electronics must have the additional property of high thermal conductivity to adequately dissipate heat from critical electrical components. The typical insulating materials are polymers, which are not sufficiently thermally conductive for heat management. Additives like ceramic nanoparticles may be mixed with polymers to improve the thermal properties, but the blended materials can be difficult to manufacture into appropriate shapes (e.g., ribbons) for insultation without introducing voids or agglomerates of the additives. Innovators at NASA’s Glenn Research Center have developed polymer composite formulations that have high thermal conductivity while maintaining the electrically insulating properties of the polymer. Additionally, NASA has developed manufacturing processes that produce high-quality, well-mixed, void-free materials. These electrically insulating and thermally conductive composites may be used as insulation for electrical components in electric motors, power generation, or in healthcare equipment.