Cure kinetics characterization and monitoring of an epoxy resin using DSC, Raman spectroscopy, and DEA

The use of thick sections of fiber-reinforced polymers (FRPs) is increasing for numerous industrial applications such as wind turbine blades. In situ cure monitoring is very important to directly observe the cure process of FRPs during the manufacturing process. In this work, Raman spectroscopy and dielectric analysis (DEA) are investigated for in situ cure monitoring of an epoxy resin. The cure behavior is first characterized using differential scanning calorimetry (DSC) as a baseline comparison, and the best-fit phenomenological reaction model is determined to describe the cure behavior of the epoxy resin as well as the kinetic parameters. The relationship between Tg and degree of cure is also established. The degree of cure obtained from Raman spectroscopy and DEA under isothermal conditions is compared to that obtained from DSC. A good agreement is observed among the three methods, supporting the potential of these in situ cure monitoring methods during manufacturing. An implementation plan for in-plant monitoring is also discussed.