Cure Modelling and Monitoring for Isothermal Processing of Fast-Curing Epoxy Resin

Area of Science:

• Materials Science
• Chemical Engineering
• Polymer Science

Background:

• Liquid composite molding (LCM) relies on precise control of thermoset curing for quality and efficiency.
• Inadequate monitoring leads to under-cured parts or reduced production speed.
• Optimizing LCM requires reliable cure kinetics modeling and real-time process monitoring.

Purpose of the Study:

• To model the cure kinetics of a fast-curing epoxy resin system using the Grindling model.
• To develop a sensor-based system for real-time degree of cure estimation during isothermal processing in LCM.
• To validate the model's predictions against experimental data and assess the impact of temperature measurement accuracy.

Main Methods:

• Utilized dynamic and isothermal differential scanning calorimetry (DSC) for model parameter identification.
• Employed the Grindling kinetic model and DiBenedetto relationship for cure kinetics and glass transition temperature description.
• Developed an experimental mold with temperature sensors for real-time cure monitoring and validated predictions with post-process DSC analysis.

Main Results:

• The Grindling model successfully described the cure kinetics, including diffusion control and vitrification.
• Real-time degree of cure estimation showed improved accuracy after implementing temperature correction for sensor deviations.
• Validated predictions demonstrated significant agreement with post-process DSC measurements, confirming model applicability.

Conclusions:

• Combining kinetic modeling with accurate temperature monitoring enables reliable real-time estimation of the curing state for fast-curing epoxy systems in LCM.
• Accurate temperature measurement is critical for successful curing monitoring in composite manufacturing.
• The study provides practical insights for implementing sensor-based monitoring in LCM processes.