Radiation-Tolerant Thermal Interface Material with High Thermal Conductivity and Adhesion for LHC Applications

The Large Hadron Collider in Switzerland is the largest particle accelerator in the world. An upgrade bringing higher resolution (higher luminosity) is called HL-LHC and will require improved lightweight materials. Thermal interface materials having higher thermal conductivity (> 4 W/mK) with low atomic mass and excellent radiation-resistance are required to achieve tight tolerances on detectors. A nanostructured carbon system is combined with a polymer such that the composite is flexible and can provide efficient infrared heating. The electrical and thermal properties can be controlled by the size, shape, loading, and selection of nanostructured carbon. This compliant thermal interface material has room-temperature thermal conductivities in the x-y plane of 5-11 W/mK range and densities between 0.7-1.3 g/cc. Adhesion is presently possible through solvation of the polymer binder. The system is primarily composed of carbon and hydrogen, with limited amounts of oxygen and nitrogen. The objective of the Phase I effort is to make a microstructure with nearly isotropic thermal conduction in excess of 4 W/mK using a polymer system that retains flexibility while leading to improved adhesion and high radiation- resistance. Radiation exposure and subsequent testing will determine if this new material is superior in performance compared to epoxy-based thermal interface materials presently in use. The Phase II work will produce large-scale (up to one meter in diameter) thermal interface materials with adhesive strengths in excess of one MPa and thermal conductivity > 10 W/mK in the through-thickness direction to meet specific needs within the High-Luminostiy, Large Hadron Collider. Thermal interface materials with higher thermal conductivities can be used for dissipating heat from a wide range of electronic devices. These materials also have the ability to shield electromagnetic interference and can be used as infrared heaters for a variety of applications. Filled-polymers with enhanced thermal conductivities and electrically conductivity can be molded, extruded, or cast to produce new grades for more demanding applications.