NPD, a research and development business, focuses on self-repairing, self-sensing, and self-forming composites. primary focus to date has been on development of self-repairing aircraft wings for the Air Force. Other technologies under development include self-sensing composites and self-repairing polymer materials for use in boats, automobiles and bridges. Self-repairing, fiber reinforced matrix materials consist of a matrix material, which includes inorganic as well as organic matrices, as well as reinforcements disposed within the matrix, hollow fibers having a selectively releasable modifying agent contained therein. The hollow fibers may be inorganic or organic and of any desired length, wall thickness or cross-sectional configuration. The modifying agent is selected from materials capable of beneficially modifying the matrix fiber composite after curing. The modifying agents are selectively released into the surrounding matrix in response to a predetermined stimulus, be it internal or externally applied. The hollow fibers may be closed off or even coated to provide a way to keep the modifying agent in the fibers until the appropriate time for selective release occurs. Self-repair, reinforced matrix materials capable of repairing microcracks, and/or releasing corrosion inhibitors or permeability modifiers are described as preferred embodiments in concrete and polymer based materials or products.
