Aerofoam

This technology uses a layered architecture that couples two complementary mechanisms. Polymer aerogels, with extremely small pores and high surface area, create tortuous pathways that dissipate structure-borne vibration (damping). Open-cell melamine foam captures airborne sound through viscous and elastic losses in the cellular network (absorption). By varying layer order, thickness, and chemistry, the composite becomes a tunable gradient system and can be designed for specific vibro-acoustic signatures, such as targeted frequency bands and mixed noise/vibration environments. Configurations can include melamine foam, compressed melamine, and melamine/aerogel sub-layers to balance absorption and damping in a single, thin envelope. Beyond acoustic performance, the aerogel component contributes low thermal conductivity. This enables insulation that reduces mass and volume while improving thermal management in panels, liners, and enclosure inserts and it integrates readily with existing structures as bonded or mechanically fastened layers. The layers can range from small samples to large panels for system-level installations. The technology has been validated from small test pieces to 8-foot panels where the layered composite can be tuned via stack order, thickness, and compression (melamine, compressed melamine, melamine/aerogel) to target specific frequency bands while retaining low thermal conductivity and low mass. This technology is assessed at TRL 6 and is available for patent licensing.

The approach in developing the LCX system was to provide a combination of advantages in thermal performance, structural capability, and operations. The system is particularly suited for the complex piping, tanks, and apparatus subjected to the ambient environment common in the aerospace industry. The low-cost approach also lends the same technology to industrial applications such as building construction and chilled-water piping. The system can increase reliability and reduce life cycle costs by mitigating moisture intrusion and preventing the resulting corrosion that plagues subambient-temperature insulation systems operating in the ambient (humidity and rain) environment. Accumulated internal water is allowed to drain and release naturally over the systems normal thermal cycles. The thermal insulation system has a long life expectancy because all layer materials are hydrophobic or otherwise waterproof. LCX systems do not need to be perfectly sealed to handle rain, moisture accumulation, or condensation. Mechanically, the LCX system not only withstands impact, vibration, and the stresses of thermal expansion and contraction, but can help support pipes and other structures, all while maintaining its thermal insulation effectiveness. Conventional insulation systems are notoriously difficult to manage around pipe supports because of the cracking and damage that can occur. Used alone or inside another structure or panel, the LCX layering approach can be tailored to provide additional acoustic or vibration damping as a dual function with the thermal insulating benefits. Because LCX systems do not require complete sealing from the weather, it costs less to install. The materials are generally removable, reusable, and recyclable, a feature not possible with other insulation systems. This feature allows removable insulation covers for valves, flanges, and other components (invaluable benefits for servicing or inspection) to be part of original designs. Thermal performance of the LCX system has been shown to equal or exceed that of the best polyurethane foam systems, which can degrade significantly during the first two years of operation. With its inherent springiness, the system allows for simpler installation and, more importantly, better thermal insulation because of its consistency and full contact with the cold surface. Improved contact with the cold surface and better closure of gaps and seams are the keys to superior thermal performance in real systems. Eliminating the requirement for glues, sealants, mastics, expansion joints, and vapor barriers provides dramatic savings in material and labor costs of the installed system.

This technology (AERoBOND) enables the assembly of large-scale, complex composite structures while maintaining predictable mechanical and material properties. It does so by using a novel barrier-ply technology consisting of an epoxy resin/prepreg material with optimal efficiency, reliability, and performance. The barrier-ply materials prevent excessive mixing between conventional composite precursors and stoichiometrically-offset epoxy precursors during the cure process by forming a gel early in the cure cycle before extensive mixing can occur. The barrier ply is placed between the conventional laminate preform and the stoichiometrically-offset ply or plies placed on the preform surface, thus preventing excessive mass transfer between the three layers during the cure process. In practice, the barrier ply could be combined with the offset ply to be applied as a single, multifunctional surfacing layer enabling unitized assembly of large and complex structures. The AERoBOND method is up to 40% faster than state-of-the-art composite manufacturing methods, allows for large-scale processing of complex structures, eliminates the potential for weak bond failure modes, and produces composites with comparable mechanical properties as compared with those prepared by co-cure.

Next generation aircraft are anticipated to be largely made with composite components, requiring significant increases in manufacturing rates of composites to meet the demand for a new fleet of aircraft. The higher rate manufacturing will require multiple advances, including rapid curing and lower processing temperatures. These requirements can be enabled by new processing methods such as isothermal rapidly cured composite parts. NASA has developed materials and methods that meet those stringent requirements for high-rate manufacturing. The innovators have demonstrated at least two families of new resin formulations that meet the expected high-rate manufacturing needs. These new formulations have been engineered to be infused and cured at the same (i.e., isothermal) temperature, below that of commercially available materials. The materials can then be removed from the mold while still hot without distorting the shape, thereby reducing the processing times by eliminating the need for cooling to occur in the mold. After a post-cure process - which takes 4 hours or less and can be performed in batches - the mechanical properties of NASA's next-gen composites. The related patent is now available to license. Please note that NASA does not manufacturer products itself for commercial sale.

Aerogels are highly porous, low-density solids with extremely small pore sizes, making them superior insulators. However, most silica aerogels are fragile. The NASA Glenn team is the first to synthesize polyimide aerogels by cross-linking through an aromatic triamine or polyhedral oligomeric silsesquioxane, octa-(aminophenyl)silsesquioxane, and chemically imidizing at room temperature. The result is a cross-linked polyimide aerogel that retains the beneficial characteristics and strength of polyimide materials and adds the beneficial properties of aerogels, but without the brittle and fragile nature of silica aerogels. Silica aerogels on the market now are available in particulate form or as a composite blanket. These aerogels are fragile and shed dust particles. The cross-linked polyimide aerogels have much better mechanical properties than silica aerogels and do not shed dust particles. They can be fabricated or machined into net shape parts, which are strong and stiff, or cast as thin flexible films with good tensile properties. Extremely customizable, the innovation can be formed into any configuration (e.g., wrapped around a pipe, sewn into protective clothing, or molded into a panel to act as a heat shield in a car). For example, a square "patch" antenna fabricated on a customized low density, low dielectric constant polyimide aerogel substrate exhibits larger bandwidth, lower mass, and superior implementation capability than conventional antennas designed for the same frequency of operation. The polyimide aerogel antenna can be tailored regarding composition, porosity, thickness, dielectric constant, and radio frequency (RF) transmission losses, which allows for optimization of bandwidth, impedance matching, and gain, which are critical for improving aerospace communication systems. The use of flexible aerogel substrates in the antenna design would enable antennas to be wrapped for conformal/curved surfaces such as aircraft wings and fuselage, sounding rockets (nanosats), missile cones, etc. Non-aerospace applications could include automotive (e.g., collision avoidance systems), radio frequency identification (RFID) tags, wearable antennas for short range wireless biomedical applications.