Long‐term behavior of partially cured epoxy prepreg systems under tensile loading

Abstract For the determination of the influence of processing conditions on the long‐term behavior of high performance thermoset composites, two different glass fiber laminate systems with varying degrees of cure were examined. The laminates were conditioned in both moist and dry environments, and characterized via thermoanalytical and mechanical investigations. During the progression of moisture conditioning, both systems exhibited a reduction in the measured glass transition temperature as a result of the plasticization of the matrix. Tensile tests revealed that a direct correlation exists between the processing conditions and the long‐term performance. Employing a linear model, the long‐term mechanical behavior as a function of processing and moisture absorption can be described. Thus, the manufacturer has access to a tool for calculating the mechanical and thermomechanical properties depending on the processing and environmental conditions. Polym. Compos. 25:289–297, 2004. © 2004 Society of Plastics Engineers.