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Properties of impregnation resin added to multifunctional epoxy at cryogenic temperature



A multifunctional epoxy tetraglycidyl dibenzmethyldiamine and triglycidyl benzylamine were blended, respectively, into impregnation resin, which mainly consists of diglycidyl ether of bisphenol A (DGEBA) and acid anhydride hardener. This resin is expected to impregnate HT-7U superconducting Tokamak toroidal field coils and improve the fracture toughness of DGEBA–acid anhydride resin at cryogenic temperature. However, the experimental results reveal that resin lap shear strengths decrease remarkably both at ambient and liquid nitrogen temperatures. After blending multifunctional epoxy for several hours, its viscosity increased quickly at room temperature. The usable potting life is too short to impregnate large coils such as those used in fusion reaction. By FTIR the possible reason was investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1385–1389, 2003