Permanently Tacky, Repositionable, Enduring Adhesives for Reduced Outer Mold Line Maintenance

NanoSonic specializes in the design and synthesis of non-commodity, wide service temperature range (-120C to > 350C), polar poly(organosiloxanes) pressure sensitive adhesives (PSAs). NanoSonic has demonstrated that the mole fraction of polar sidechain units dictates the adhesive peel strength; and the mole fraction of crosslink sites, or crosslink density, controls the adhesive failure mode. For this program, repositionable, permanently tacky PSAs with adhesive peel strength of ≥ 2 lbf/in. (per ASTM D 903) and adhesive failure (at the adhesive-substrate interface, rather than within the adhesive bondline) are offered. The advanced PSAs with in-situ ultra-hydrophobic nanostructured modifiers are expected to result in decreased outer mold line maintenance, leave no residue or damage upon removal, and significantly improve long-term durability in hot-wet environments (≥ 95% humidity). Together, the advanced PSA and primer are expected to significantly reduce the Direct Maintenance Man Hours per Flight Hour (DMMH/FH). TRLs of 5 and 7 would be achieved completion of the Phase I and Phase II programs via demonstration of joining extruded polymer parts to military aircraft panels in a wind tunnel alongside current-off-the-shelf PSAs. TRL 9 would be reached via successful flight testing and PSA integration onto legacy and future military and civil aircraft. BENEFIT: The PSAs with in-situ nanostructured hydrophobic primers shall be developed as long term durability adhesives for bonding polymer extruded parts to military aircraft panels. Additional applications for the ultra-hydrophobic, nanostructured, modifiers and high performance, halogenated, POSS-copolymers include moisture/corrosion mitigating structural aerospace adhesives, anti-ice conformal coatings and gamma radiation resistant composites. At the systems level, the moisture resistant, environmentally tunable adhesive systems would prevent the spontaneous bond dissociation associated with water wicking at the metal-epoxy interface of bonded joints. In humid environments, diffusion through the bulk epoxy adhesive on composite-composite bonded joints would be mitigated via a reduction in the free volume of the water permeable epoxy. The universal nanostructured modifiers could therefore support composite or metal aircraft substructures. Of importance to manufacturability and dual-use commercialization, the novel modifying agents are inert, inorganic-organic hybrid, halogenated copolymers, and can therefore be used with virtually any adhesive, paint or environmental aerospace materials systems.