Cure kinetics behavior of a functionalized graphitic nanofiber modified epoxy resin

Understanding curing behavior of nano-modified thermoset resin is critical for many applications. An appropriate incorporation of nanoparticles can stimulate improvements to many properties of epoxy resins when used as matrices in fiber reinforced composites. In this study, the curing behavior of an epoxy resin modified by a type of reactive graphitic nanofibers (r-GNFs), that were previously developed, was characterized using a dynamic differential scanning calorimetry (DSC) method. The activation energy of pure epoxy resin and the r-GNF modified epoxy resin during the cure reaction was determined based on a model-free method. The results from DSC kinetic analysis indicated that the addition of the r-GNFs offered a catalytic action for cure reaction of epoxy resin at high temperature range so that a larger extent of cure was obtained over pure epoxy. The faster curing behaviors of the r-GNF modified epoxy system will be essential for enabling future energy efficient infusion processing for manufacturing high quality and high performance structural composite applications.

Research highlights
► A model-free method without assumption of constant activation energy was used to determine the activation energy of epoxy system.
► It revealed that addition of the r-GNFs offered a slight retarding at the early curing stage and a catalytic action at high temperature range, which can lead to improved wetting on fiber reinforcement surface at the early curing stage.
► A more efficient cure cycle due to the catalytic curing behavior at high temperature range.