The objective of the project is to refine a new method for the synthesis of epoxy functional alternative crosslinking polyurethane resins and provide an extensive study of structure-property relationships for applications in coatings and sealant formulations, optimize the synthesis and resin compositions. The systems eliminate the use of isocyanates by the end user and do not include any other chemicals of concern. 

The program involves the systematic exploration of epoxy-functional polyurethane resins having varying backbone structures and numbers of epoxy functional groups. The resins are synthesized using low-cost reagents and an epoxidation process that has the potential to have improved life cycle benefits. These resins will then be crosslinked at ambient conditions with amine curing agents to form coatings. The coatings will be extensively evaluated for their state of cure, physical, thermal, and mechanical properties. Coatings systems that have performance properties matching that of several specific Department of Defense (DoD) coating systems will be further formulated into pigmented systems and subjected to more extensive corrosion and durability testing. Experiments will also be carried out to further optimize the synthesis process in order to make it more amenable to commercial production and to study the curing kinetics of these novel epoxy functional polyurethane systems. The Naval Research Laboratory will also carry out evaluations of resin and coating candidates. Both Techno-Economic Analysis and Lifecycle Assessment will be used to assess the new coatings systems in comparison to conventional polyurethane systems in use by the DoD. 

This program will provide the DoD with new coatings that reduce personal protective equipmentburden and engineering control costs associated with the use of isocyanatesand can be potential replacement systems for current DoD coatings systems used on ground vehicles and aviation assets. The coatings technology developed in this project may improve asset operational performance, readiness, and application/removal production and field throughput characteristics that would reduce life cycle costs for these coatings.