Viscoelastic properties of an epoxy resin during cure

The cure dependent relaxation modulus of an epoxy resin was investigated ov er the entire range of cure extent. Parallel plate rheometry was used to me asure the material behavior below the gel point of the epoxy network. Creep testing in three-point bend was used for specimens cured past gelation. Al l data were converted to the stress relaxation modulus for comparison of th e material behavior among the various cure states and between the two exper imental techniques. The data were used to develop a practical model for pre dicting the cure dependence of the relaxation modulus throughout cure under varying processing conditions.