Radical-Assisted Photochemical Stripping of Aircraft Coatings

We propose to demonstrate proof-of-concept of a novel two-stage chemical-electrochemical approach for the stripping of paint. This approach will result in the creation of paint flakes which are dispersed in the aqueous medium to be used for the stripping process. Thus, unlike chemical stripping procedures, collection and disposal of the process liquid will be considerable simpler and less expensive. Furthermore, unlike the plastic media blasting technology, airborne particulates are not generated thus making this procedure more enviornmentally friendly. In the first stage of the process, the paint is chemically degraded by hydroxyl radical attack. These hydroxyl radicals will be generated by Fenton's chemistry or by the photolysis of hydrogen peroxide. The first stage establisheds electrical connectivity between the aqueous (salt_ electrolyte, substrate/primer interface. The second stage dislodges the degraded top layers of the coatings via the generation of hydrogen gas. We propose a Phase I work plan comprising five tasks to demonstrate this new concept and to pave the way for subsequent tests with larger substrates and surfaces other than aluminum.