Aging and filler effects on the creep model parameters of thermoset composites

The effect of marble mineral filler on the creep response of polyester thermoset matrix before and after physical aging has been investigated. A number of composites with different filler content (0.29, 0.38, 0.45, 0.55) have been studied in order to understand the role of the filler for the creep response. A mathematical model has been chosen for interpreting the experimental results, its parameters having a definite physical sense and being related with the single components of deformation under creep conditions. This model represents the generalized equation of Maxwell for relaxing isotropic medium in the form presented by G.I. Gourevich (Maxwell–Gourevich equation). The influence of the filler and physical aging on the parameter values of the model has been discussed, respectively on the elastic and rubberlike elastic (inelastic) deformation. The possibilities of the proposed model to describe the creep response of the matrix and the composites before and after physical aging are shown.