Effects of moisture and stoichiometry on the dynamic mechanical properties of a high-performance structural epoxy

Dynamic mechanical measurements have been made on a 4,4′‐diaminodiphenyl sulfone‐cured tetraglycidyl 4,4′‐diaminodiphenylmethane epoxy (TGDDM‐DDS). There are basically three transitions on the mechanical spectra that have been identified, and the effects of moisture uptake and amount of DDS on these transitions were examined. The dynamic mechanical behavior of the same epoxy with 60% carbon fiber loading was also studied, providing further elucidation on the nature of the transitions observed with this system.