NASA Scientific and Technical Aerospace Reports

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COMPOSITE MATERIALS
Includes physical, chemical, and mechanical properties of laminates and other composite materials.
20040111079 NASA Langley Research Center, Hampton, VA, USA
Clear, Conductive, Transparent, Flexible Space Durable Composite Films for Electrostatic Charge Mitigation
Watson, Kent A.; Connell, John W.; Delozier, Donavon M.; Smith, Joseph G., Jr.; 8th Spacecraft Charging Technology
Conference; March 2004; 14 pp.; In English; See also 20040111031; No Copyright; Avail: CASI; A03, Hardcopy
Space environmentally durable polymeric films with low color and sufficient electrical conductivity to mitigate
electrostatic charge (ESC) build-up have been under investigation as part of a materials development activity. These materials
have potential applications on advanced spacecraft, particularly on large, deployable, ultra-light weight Gossamer spacecraft.
The approach taken to impart sufficient electrical conductivity into the polymer film while maintaining flexibility is to use
single wall carbon nanotubes (SWNTs) as conductive additives. Approaches investigated in our lab involved an in-situ
polymerization method, addition of SWNTs to a polymer containing reactive end-groups, and spray coating of polymer
surfaces. The work described herein is a summary of the current status of this project. Surface conductivities (measured as
surface resistance) in the range sufficient for ESC mitigation were achieved with minimal effects on the physical, thermal,
mechanical and optical properties of the films. Additionally, the electrical conductivity was not affected by harsh mechanical
manipulation of the films. The chemistry and physical properties of these nanocomposites will be discussed.
Author
Polymeric Films; Nanocomposites; Thin Films; Spacecraft Charging
20040111081 Raytheon Missile Systems Co., Tucson, AZ, USA
The Viability of Using Weight-Saving Material for Future Long-Term Space Vehicles (i.e., Satellites)
Burgess, Nicola; Splitek, Sarah; Lassise, R. Michael; 8th Spacecraft Charging Technology Conference; March 2004; 14 pp.;
In English; See also 20040111031; No Copyright; Avail: CASI; A03, Hardcopy
The potential hazards of the natural space environments to a composite structure and to the systems within the structure
are compared to an all conductive (metal) structure. Low Earth Orbit (LEO) will be the focus of the evaluation. The natural
space environments comprise a multitude of risks, with a primary concern being the natural space plasma and the resulting
spacecraft charging. Various other aspects of the environment and their impacts on a composite structure will also be
examined. The evaluation of spacecraft charging demonstrates a high probability of electrical overstress (EOS). The majority
of space vehicles are made of a combination of metal and composites, indicating a concern of EOS (arcing) between the
materials. To avoid EOS, you must have the entire vehicle at the same potential. Different materials will not have the same
discharge voltage, allowing one to charge at a higher voltage than the other. This causes a potential difference and allows for
EOS. The composite is not a good conductor and has a dielectric constant associated with it. The rate of charging and the
distribution of charge will vary non-linearly, causing a nonuniform distribution of charge. EOS allows degradation of the on
board systems, leading to possible mission failures. EOS may cause physical damage to composites, which can lead to a loss
of structural integrity.
Author
Aerospace Environments; Low Earth Orbits; Aerospace Vehicles; Composite Materials; Structural Weight
20040111220 NASA Glenn Research Center, Cleveland, OH, USA
Thermomechanical Properties of M40J Carbon/PMR-II-50 Composites
Allred, Ronald E.; Shin, E. Eugene; Inghram, Linda; McCorkle, Linda; Papadopoulos, Demetrios; Wheeler, Donald; Sutter,
James K.; [2003]; 13 pp.; In English; SAMPE 2003: Advancing Materials in the Global Economy: Applications, Emerging
Markets and Evolving Technologies, 11-15 may 2003, Long Beach, CA, USA
Contract(s)/Grant(s): 708-31-16; Copyright; Avail: CASI; A03, Hardcopy
To increase performance and durability of high-temperature composites for potential rocket engine components, it is
necessary to optimize wetting and interfacial bonding between high modulus carbon fibers and high-temperature polyimide
resins. It has been previously demonstrated that the electro-oxidative shear treatments used by fiber manufacturers are not
effective on higher modulus fibers that have fewer edge and defect sites in the surface crystallites. In addition, sizings
commercially supplies on most carbon fibers are not compatible with polyimides. In this study, the surface chemistry and
energy of high modulus carbon fibers (M40J and M60J, Torray) and typical fluorinated polyimide resins, such as PMR-II-50
were characterized. A continuous desizing system that uses an environmentally friendly chemical-mechanical process was
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