NASA Scientific and Technical Aerospace Reports

single-walled carbon nanotubes (SWNT) solutions were dispersed in solutions of a novel ionomer in N,N-dimethylacetamide
resulting in homogenous suspensions or quasi-solutions. The ionomer was used to aid in the dispersal of SWNTs in to a
soluble, low color space environmentally durable polyimide. The use of the ionomer as a dispersant enabled the nanotubes
to be dispersed at loading levels up to 3 weight % in a polyimide solution without visual agglomeration. The films were further
characterized for their electrical and mechanical properties.
Author
Carbon Nanotubes; Polymeric Films; Electrostatic Charge; Agglomeration; Polyimides
20040073505 NASA Marshall Space Flight Center, Huntsville, AL, USA
Graphite/Ultra-High Modulus Polyethylene Hybrid Fiber Composites with Epoxy and Polyethylene Matrices for
Cosmic Radiation Shielding
Biological and Physical Space Research Laboratory 2002 Science Review; December 2003, pp. 8; In English; See also
20040073490; No Copyright; Abstract Only; Available from CASI only as part of the entire parent document
One of the most significant technical challenges in long-duration space missions is that of protecting the crew from
harmful radiation. Protection against such radiation on a manned Mars mission will be of vital importance both during transit
and while on the surface of the planet. The development of multifunctional materials that serve as integral structural members
of the space vehicle and provide the necessary radiation shielding for the crew would be both mission enabling and cost
effective. Additionally, combining shielding and structure could reduce total vehicle mass. Hybrid laminated composite
materials having both ultramodulus polyethylene (PE) and graphite fibers in epoxy and PE matrices could meet such mission
requirements. PE fibers have excellent physical properties, including the highest specific strength of any known fiber.
Moreover, the high hydrogen (H) content of polyethylene makes the material an excellent shielding material for cosmic
radiation. When such materials are incorporated into an epoxy or PE matrix a very effective shielding material is expected.
Boron (B) may be added to the matrix resin or used as a coating to further increase the shielding effectiveness due to B s ability
to slow thermal neutrons. These materials may also serve as micrometeorites shields due to PE s high impact energy absorption
properties. It should be noted that such materials can be fabricated by existing equipment and methods. It is the objective of
this work therefore to: (a) perform preliminary analysis of the radiation transport within these materials; (b) fabricate panels
for mechanical property testing before and after radiation exposure. Preliminary determination on the effectiveness of the
combinations of material components on both shielding and structural efficiency will be made.
Author
Graphite-Epoxy Composites; Epoxy Matrix Composites; Radiation Shielding; Hybrid Composites; Matrix Materials;
Polyethylenes
20040073509 NASA Marshall Space Flight Center, Huntsville, AL, USA
Nanophase and Composite Optical Materials
Biological and Physical Space Research Laboratory 2002 Science Review; December 2003, pp. 11; In English; See also
20040073490; No Copyright; Abstract Only; Available from CASI only as part of the entire parent document
This talk will focus on accomplishments, current developments, and future directions of our work on composite optical
materials for microgravity science and space exploration. This research spans the order parameter from quasi-fractal structures
such as sol-gels and other aggregated or porous media, to statistically random cluster media such as metal colloids, to highly
ordered materials such as layered media and photonic bandgap materials. The common focus is on flexible materials that can
be used to produce composite or artificial materials with superior optical properties that could not be achieved with
homogeneous materials. Applications of this work to NASA exploration goals such as terraforming, biosensors, solar sails,
solar cells, and vehicle health monitoring, will be discussed.
Author
Composite Materials; Optical Materials; Space Exploration; Microgravity; NASA Programs; Porosity
20040073642 North Carolina Univ., Greensboro, NC
Neural Composite Materials
Sundaresan, Mannur J.; Schmiz, Mark J.; Dec. 30, 2003; 15 pp.; In English; Original contains color illustrations
Contract(s)/Grant(s): GDAAD19-00-1-0536
Report No.(s): AD-A422526; NCM-IR-00; ARO-41484-EG-H-2; No Copyright; Avail: CASI; A03, Hardcopy
An embeddable structural health monitoring system has been developed to measure acoustic emission signals generated
by incipient damage in Army structures. The structural health monitoring system is built upon two parallel approaches that
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