Cure kinetics and rheology characterisation and modelling of ambient temperature curing epoxy resins for resin infusion/VARTM and wet layup applications

Ambient temperature curing epoxy resins are widely used as the matrix material in fibre reinforced plastics in the marine and wind energy sectors, where they are popular due to their relatively high mechanical performance yet low processing and tooling costs. To date, the characterisation of ambient curing epoxy resins has been limited to relatively simple measures, not suitable for use in heat transfer and flow process models. A complete cure kinetics and rheology model allows the prediction of the progression of degree of cure and viscosity for any time-temperature history. The progression of degree of cure of two epoxy resin systems was measured by differential scanning calorimeter and fitted to an nth order model incorporating vitrification effects. Viscosity was measured using an oscillatory rheometer and fitted to a model from the literature. The resulting cure kinetics and rheology model enables the improvement of resin infusion and wet layup processes by providing a thorough understanding of the interlinked relationship between time, temperature, degree of cure and viscosity.