Nano-engineered Coatings Based on Functionalized Silsesquioxanes

Phase I studies comparing octaminophenylsilsesquioxane (OAPS, cube)/epoxy coating systems to diaminodi-phenylmethane/diglycidylether of bisphenol A DDM/DGEBA coatings used traditionally as undercoats on aircraft frames and skins reveal that OAPS/epoxy systems offer: (1) improved thermal stability (40-60°C higher); (2) photolytic stability 2-3x DDM/DGEBA systems; (3) lower water uptake (0.5 vs up to 7 wt %); (4) adhesion to alum-inum comparable to DDM/DGEBA (5) CTEs equivalent to aluminum alloys (20-30 ppm) compared to 50-80 ppm for the best current epoxy resins; (6) good shelf life without accelerators; (7) VOC free processability for repair applications; (8) the potential to include nanoalumina powder to improve scratch resistance, and (9) potential as barrier coatings for carbon fiber composites. In Phase II we will: (1) further scale syntheses of cubes found useful in Phase I, (2) develop on subcontract with the University of Michigan, new materials including [(NH2)2C6H5SiO1.5]8 and [NH2C6H5SiO1.5]12 cheaper and cleaner routes to OAPS; (3) optimize superior coating systems from Phase I and identify new ones particularly for barrier properties; (5) develop in-house skills for coatings processing and testing via cooperative studies with Boeing, (6) create a knowledge base for prospective customers; and (7) provide 1-10 liter samples of coating systems and/or coated panels.