Description: Carbon Polymer Matrix Composites (PMCs) are attractive structural materials for NASA applications due to their high strength to weight ratio, mechanical properties that can be tailored to specific applications, and fatigue resistance. Reinforcing specific critical areas in PMCs is most advantageous for structural durability. Since carbon nanotubes (CNTs) have exceptionally high tensile strength, they can be used as a functional additive to enhance the mechanical properties of PMCs in these critical areas. However, there are known issues with dispersing and aligning CNTs in the polymer matrix, thus limiting their strength-bearing properties. The proposed Phase I program aims to demonstrate a novel means of incorporating aligned CNTs specifically, and only, where they are needed during fabrication of a PMC component structure, thus limiting their use to specific areas where they are wanted. The key innovation uses a commercially-viable nanofiber technology to both disperse and to align the CNTs. The continuous nanofibers will be formed into Nanofiber-Reinforcing Mats (NRMs) which will be used during layup of the carbon PMC structure and placed only where added reinforcement is needed. For demonstration of feasibility in Phase I, prepregs will be used, but the concept is adaptable to other forms of PMC manufacturing such a filament winding. In Phase II we will scale-up the technology and fabricate large test samples, which will involve working with a prepreg manufacturer and fabricator of PMC component parts, in order to meet NASA specifications.

Benefits: The specific NASA applications for the technologies we propose to develop are for light weight structures such as would be used for in-space applications and launch vehicles. In addition, the developed technologies would find use in NASA aerospace applications such as rockets, aircraft, aircraft/spacecraft propulsion systems, and supporting facilities. The reinforcing aspect of the developed technology will allow for more efficient joining of fiber composite parts, thus offering additional weight-savings. More robust structures capable of withstanding micrometeoroid and space debris impacts will be possible with the enhanced mechanical properties imparted by the aligned CNTs incorporated into the fiber composite structure, as well as the potential for improved electrical and thermal properties.

Commercial applications of the proposed technology are many, especially as fiber composites have made their way into various markets. It will be especially useful in applications where added reinforcement is needed in specific critical areas and where weight savings may be crucial. PMC components and parts are used in commercial aircraft (e.g., cargo floor panel, nose strake, air conditioning duct) and sporting goods (e.g., tennis rackets, ski equipment, fishing rods and golf clubs). The automotive industry has increasingly used PMCs – the average automobile today has about 250 lbs of plastics and composites. Another application of these materials is in bridge "rehabilitation". Other applications would include composite overwrapped pressure vessels (COPVs), such as lighter and safer fuel storage in automobiles and buses that run on hydrogen fuel; chemical processing and pharmaceutical manufacturing, oil exploration involving offshore drilling, oil production and petroleum refineries; on-the-road transport of refrigerants such as liquid oxygen or liquid nitrogen; and self-contained breathing apparatus tanks for firefighters and homeland security.