Cryogenic Durability of a Carbon Fiber Reinforced Cyanate Ester Composite: Degree-of-Cure Effect

The James Webb Space Telescope (JWST) will be located approximately 1.5 million kilometers from Earth, producing extremely cold temperatures on the optical portion of the observatory. Specifically, the Optical Telescope Element (OTE) and Integrated Science Instrument Module (ISIM) will operate at approximately -240 C. Construction of the structural components of the OTE and ISIM require bonding dissimilar materials together, e.g. Invar-36 (an iron-nickel alloy) to a carbon fiber reinforced cyanate ester composite (CFRCE) with an epoxy adhesive. While these materials enable the cryogenic stability required for optical performance, their joint strength at these extreme conditions presents a unique design challenge. Therefore, the current study presents a detailed investigation into the optimization of cryogenic composite durability. It is demonstrated that by controlling the degree-of-cure of a laminate, one can achieve an enhanced resistance to microcracking and an improved residual strength following cryogenic cycling to -253 C.