Development of graphene and boron nitrate-based polymeric systems for electrical applications

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The general topic of this research proposal is the development of polymer-based systems for electrical applications. Functional dielectric and semi-conductive polymer-based materials are indeed used since decades for electrical power applications. These applications extend from insulating materials for the insulation walls in power cables, high voltage capacitors, large rotating machines, to semiconducting materials for conductor and insulation screens and outer corona protection coatings, as well as for stress grading applications for which polymer-based composites have been found to be effective when used as resistive stress grading materials. This class of materials also features many advantages such as low cost, processability at the industrial scale and the possibility to tailor their electrical, mechanical and thermal properties with either molecular additives or reinforcing nanoparticles, usually inorganic. The development of next-generation electrotechnical apparatus, such as DC transmission infrastructures, relies in part on the development of new dielectric systems with specific properties. Resistance to space charge accumulation, which is not required for AC applications but critical for High Voltage DC (HVDC) applications, is an example of new requirement that was completely ignored in the past but will be relevant in the future. This research proposal will aim to investigate and optimize the properties of several types of polymeric nanocomposites (PNC) for dielectric and electrical applications. The first system that will be investigated in this research proposal is graphene-based polymeric systems that are now slowly becoming economically viable nanocomposites since mass produced graphene is now available (actually one of the biggest provider is a Canadian company) which makes this product readily available at the industrial scale at a reasonable cost. The application of these composites ranges from insulating systems for HVDC cables at very low concentration, to resistive stress grading systems at concentration in the vicinity of the percolation threshold up to semi-conductive systems for concentration above the percolation threshold. There are many advantages to these systems compared with conventional carbon black loaded polymers but there is still a lot of development and optimization needed before the appearance of widespread commercialized graphene-containing devices. The second system that will be investigated and optimized in this research program are epoxy Boron Nitrate NanoTubes (BNNT) systems that are promising material for many application where a balance of properties are needed such as good insulating properties and high thermal conductivity, which usually is contradictory. Machine insulation, energy storage capacitors and dry-type high voltage capacitors as well as aerospace applications are some potential niche for these material systems.