Coefficient of thermal and moisture expansion and moisture absorption for dimensionally stable quasi-isotropic high-modulus graphite fiber/epoxy composites

In order to develop dimensionally space stable laminate composite structures a detailed understanding of moisture absorption of composite laminates and the effect of"dryout" on the shrinkage oflaminate structures in the space environment is required. Several new epoxy resins have recently been introduced which are reported to absorb less moisture than the baseline epoxy resins currently used for fabrication of space structures. These are 3M's SP-500, Hexcel F-584 and Toray 3631and are all modified structural epoxy resins. This study describes the mechanical properties and moisture absorption ofthese laminates as well as detailing the coefficient ofthermal expansion and moisture expansion for quasi-isotropic graphite laminates made from these resin systems.