Gamma irradiation effects on cyanate ester/epoxy insulation materials for superconducting magnets

• Irradiation resistance of glass fiber reinforced cyanate ester/epoxy composite was investigated.
• The cyanate ester/epoxy resin system has a low viscosity and long pot life.
• The Tg of the matrix resin decreased slightly with the increase of irradiation dose.
• The ILSS of GFRP composite increased slightly when exposed to 10 MGy of gamma irradiation.

Cyanate ester/epoxy resin was used as a cryogenic-grade polymer matrix and glass fiber reinforced polymer (GFRP) composite was manufactured. The processing properties of matrix resin in terms of the isothermal viscosity at 45 °C were investigated. The specimens were exposed with gamma irradiation of 1 MGy, 5 MGy and 10 MGy, respectively. The effect of gamma irradiation on thermal properties and structure of cyanate ester/epoxy matrix was investigated. The interlaminar shear strength (ILSS) of the composites before and after irradiation were investigated at room temperature, 77 K and 4.2 K. Results showed that cyanate ester/epoxy system had a low viscosity and a long pot life at 45 °C. The glass transition temperature of the matrix resin decreased with the increasing irradiation dose. Moreover, the ILSS of GFRP composite slightly increases after irradiation and toughening mechanism was also discussed.