Cure-volume-temperature relationships of epoxy resin and graphite/epoxy composites

Abstract

Taking the material thermal expansion and curing shrinkage in polymer composites into account, this work aims to quantitatively obtain the relationships among the degree of cure, the volumetric change rate and the temperature (CVT) at the atmospheric pressure. According to reaction kinetics and nonlinear deformation theory, the mathematical models are established to implicitly describe the CVT relationships of epoxy resin as well as its unidirectional graphite fiber composites, and then the volumetric change rates of the two types of materials during curing process are obtained via the finite element method. On the basis of the numerical analysis and data fitting, two new explicit CVT expressions are constructed. The numerical analysis of the cure-volume-temperature relationships is helpful not only for the prediction of material warpage and internal stress, but also for the process optimization, such as the shrinkage compensation of polymer composites. By comparing the present results with the results in published articles, the validity of the present results is proven indirectly.