Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2008 · 13 citations · 1 references
EngineeringMaterials EngineeringMaterials ScienceMechanical Behavior Of MaterialsOptical MaterialsPolymer EngineeringMembrane EngineeringMembrane MaterialsPolymer MembranesPolymer Thin FilmsPolymeric MembranesRadiation-resistant MaterialsImage Distortion CorrectionMembrane Mechanical PropertiesPolyimidesThermal Expansion
Polyimides are attractive mirror candidate materials due to their low mass, solar radiation resistance, and cryogenic flexibility. However, polyimides exhibit high coefficients of thermal expansion (CTE) values (40-70 ppm/K), inducing image distortion from CTE mismatch. Additionally, the temperature of large aperture (10 m) membranes is not uniformly controlled in space, further increasing image distortion from anisotropic deformations. The CTE of the MSRS Novastrat polyimide line was adjusted to exhibit CTEs between -16 ppm/K and 53 ppm/K, including 0 ppm/K, 10 ppm/K, 17 ppm/K, and 25 ppm/K corresponding with CTE matches of graphite/epoxy, carbon steel, copper, and aluminum (respectively). The development of these CTE-matched membranes is presented, as well as the effect of the CTE adjustment on the mechanical properties.
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