Real-Time Cure Monitoring via Carbon Nanotube Networks Enables Mechanical Property Optimization in Post-Cured Epoxy Resins

Abstract

This research presents a single-walled carbon nanotube (SWCNT)-enabled real-time monitoring system to optimize post-curing conditions (temperature and duration) for epoxy resin. This method can serve as an alternative to traditional methods like Differential Scanning Calorimetry (DSC), which is effective in measuring the degree of cure in polymers during industrial curing (manufacturer-recommended cure cycle). Two different programs using SWCNTs were employed to design the cure cycles for investigating the development of mechanical properties: Program A as the comparison of effects of varied duration of high-temperature curing and Program B as high-temperature curing followed by the varied duration of low-temperature post-curing. By correlating variation in the electrical resistance of SWCNT with curing stages, we illustrate that extending post-curing at 100{\deg}C for 24 hours after an initial 3-hour cure at 130{\deg}C increases tensile strength by 60% and elongation by 164% compared to industry standards. This approach not only improves mechanical performance but also enables precise, non-destructive cure-state detection, offering a scalable solution for high-performance composites in the aerospace and automotive sectors.