SBIR Phase I: Dual-Capsule Epoxy Self-Healing Additives for Corrosion Protection

The broader impact/commercial potential of this project is significant due to the number of critical challenges in the design of protective materials the proposed technology could address. The proposed R&D activity will facilitate the development of a dual-capsule epoxy self-healing system for epoxy protective coatings. The incorporation of such a system into the design of protective and marine epoxy coatings will improve the corrosion resistance of these coatings leading to longer maintenance cycles for these assets along with a decrease in the loss of productivity, energy consumed and volatile organic compounds associated with maintenance, repair and overhaul activities. The product developed will also find utility as a specialty additive for adhesives and sealants spanning multiple consumer and industrial applications. Finally, successful development of this technology will enable the development of novel one-pack epoxy coating and adhesives curable at ambient conditions, curing agents for powder coatings and novel corrosion inhibiting formulations. This Small Business Innovation Research (SBIR) Phase I project will result in the development of an approach for the microencapsulation of amine curing agents for epoxy resins en route to the development of a dual capsule epoxy-based self-healing system. Due to their amphiphilic properties, curing agents for epoxies, (typically amines and amides) are difficult to encapsulate since they tend to reside at the interface between the oil and the water phases in oil-in-water emulsions that are a prerequisite for most encapsulation procedures. As such, self-healing systems demonstrated even at an academic level have been based other chemistries even in cases in which the matrix is an epoxy. We will approach this problem on two fronts. The first will be the systematic evaluation and selection of an amine curing agent with a degree of hydrophobicity that will permit its encapsulation. Upon successful encapsulation of the amine, the second front will identify an appropriate process for reinforcing the properties of the shell wall to improve its robustness. Following the achievement of adequately stable amine microcapsules, the efficacy of the dual capsule self-healing system combining these capsules with complementary microcapsules containing an epoxy resin, will be assessed in prototype coating and adhesive formulations.