Evaluation of structural changes in epoxy systems by moisture sorption‐desorption and dynamic mechanical studies

Abstract
This work forms a basis for relating moisture solubilities and dynamic mechanical properties to the hygrothermal history of epoxy systems. Two different classes of epoxy systems were investigated; a low‐performance epoxy (DGEBA‐TETA) and a high‐performance system (TGDDM‐DDS) commonly used in carbon fiber composites. An increase in the equilibrium moisture content from TGDDM‐DDS epoxy samples having various DDS compositions was observed as a result of thermal cycling in a liquid environment. Interpretation of the experimental results suggest that hygrothermal interactions produce changes in the epoxy network structure and result in the observed moisture sorption behavior.