Modified Epoxy Resin Systems as Composite Insulation in Fusion Confinement Systems

78278S Superconducting magnet coils are a major component of plasma fusion experimental devices. The electrical insulation in these magnet coils is a polymer matrix composite, which must exhibit good mechanical strength and radiation resistance at cryogenic temperatures. Current resin systems for these composites do not combine good processing characteristics (i.e., the resin must be suitable for vacuum pressure impregnation of these very large magnet coils) with mechanical strength and radiation resistance (i.e., a major problem is the release of gases by the organic material during irradiation). This project will develop silsesquioxane-epoxy resins, which will be thermally cross-linked to generate end use materials. The formulation will be systematically optimized to enhance processing properties (viscosity and pot-life), radiation resistance, and cryogenic mechanical strength. In Phase I, the effects of silsesquioxane upon epoxy radiation resistance, as measured by gas evolution experiments after irradiation, will be determined. Short beam shear, flexural, and through-thickness compressive strength will be determined for glass fiber reinforced silsesquioxane-epoxy composite specimens. These results will be compared to a pure epoxy formulation in order to determine if performance goals have been achieved. In Phase II, the optimized formulation will be fully characterized in terms of mechanical and electrical properties and in terms of radiation induced degradation and outgassing. Commercial Applications and Other Benefits as described by the awardee: Applications of the resin systems include electrical insulation for cryogenic superconducting magnet systems, particularly those which will be subjected to irradiation. In addition, the high performance resin system should find use in cryogenic and high-temperature composite structural applications, which are fabricated by liquid impregnation methods such as Resin Transfer Molding. Other potential applications exist in automotive components and parts, aerospace equipment, industrial belts and hoses, and other applications where high-temperature resistance and weatherability are required.