Closed-Cell Polymer Foams for Corrosion Control in Confined Metal Spaces

The use of closed-cell plastic polymer foams to control corrosion in hollow, irregular cavities of preexisting metallic structures or assemblages was explored. The method involved blocking the access of corrosive species to the interior surfaces by filling the empty spaces with an expanding, polymeric, rigid foam material. The fact that the foam could be injected from a remote location and then expanded to fill the void solved the problem of accessibility, which precluded the use of traditional corrosion preventive coatings in these areas. The approach differed from prior studies in that it focused on postdesign applications of corrosion inhibition within confined regions. Results of laboratory seawater exposure tests using structural steel tubular specimens with interior surfaces that were as-manufactured, precorroded, or protected with a paraffin-based corrosion preventative and filled with a one-part polyurethane foam were discussed in the context of the foam’s ability to prevent water penetration to the metal interface. Effectiveness of the method for corrosion control was demonstrated through visual comparisons of metal deterioration in treated and untreated specimens.