NASA Scientific and Technical Aerospace Reports

developed for tow level fiber. Composites were fabricated with fibers containing the manufacturer’s sizing, desized, and
further treated with a reactive finish. Results of room temperature tests show that desizing reduces interface sensitive
properties compared to the manufacturer’s sizing and that subsequent surface re-treatment with reactive finish increases
interface sensitive properties. Properties of thermally aged composites and composites with varying finish concentrations are
also discussed.
Author
Polymer Matrix Composites; Thermodynamics; Refractory Materials; Carbon Fibers; Mechanical Properties
20040111221 NASA Glenn Research Center, Cleveland, OH, USA
Studies on Hot-Melt Prepregging of PMR-II-50 Polyimide Resin with Graphite Fibers
Shin, E. Eugene; Sutter, James K.; Juhas, John; Veverka, Adrienne; Klans, Ojars; Inghram, Linda; Scheiman, Dan;
Papadopoulos, Demetrios; Zoha, John; Bubnick, Jim; [2003]; 16 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
A Second generation PMR (in situ Polymerization of Monomer Reactants) polyimide resin, PMR-II-50, has been
considered for high temperature and high stiffness space propulsion composites applications for its improved high temperature
performance. As part of composite processing optimization, two commercial prepregging methods: solution vs. hot-melt
processes were investigated with M40J fabrics from Toray. In a previous study a systematic chemical, physical, thermal and
mechanical characterization of these composites indicated that poor resin-fiber interfacial wetting, especially for the hot-melt
process, resulted in poor composite quality. In order to improve the interfacial wetting, optimization of the resin viscosity and
process variables were attempted in a commercial hot-melt prepregging line. In addition to presenting the results from the
prepreg quality optimization trials, the combined effects of the prepregging method and two different composite cure methods,
i.e., hot press vs. autoclave on composite quality and properties are discussed.
Author
Graphite; Polyimide Resins; Prepregs; Fibers; Melting; Mechanical Properties; Hot Pressing
20040111222 NASA Glenn Research Center, Cleveland, OH, USA
The Influence of Sizings on the Durability of High-Temperature Polymer Composites
Allred, Ronald E.; Wesson, Sheldon P.; Shin, E. Eugene; Inghram, Linda; McCorkle, Linda; Papadopoulos, Demetrios;
Wheeler, Donald; Sutter, James K.; [2004]; 21 pp.; In English
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. Sizings commercially supplied on most carbon fibers are not compatible with polyimides. In this study, the chemistry
of sizings on two high-modulus carbon fibers (M40J and M60J, Toray) was characterized as was the chemistry of PMR-II-50
fluorinated polyimide resin. The carbon fibers were characterized using single filament wetting, scanning electron microscopy,
fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopic measurements. The polyimide matrix resins
were coated onto glass filaments for characterization by wetting measurements. Surface energy components were obtained by
wetting with nondispersive (methylene iodide), acidic (ethylene glycol), and basic (formamide) probes. A continuous desizing
system that uses an environmentally friendly chemical-mechanical process was developed for tow level fiber. Composites
were fabricated with fibers containing the manufacturer’s sizing, desized, and further treated with a reactive finish. Results of
room-temperature tests after thermal aging show that the reactive finish produces a higher strength and more durable interface
compared to the manufacturer’s sizing. When exposed to moisture blistering tests, however, the better bonded composite
displayed a tendency to delaminate, presumably due to trapping of volatiles.
Author
Durability; Polyimide Resins; Polymer Matrix Composites; Mechanical Properties; Sizing Materials; Fabrication; Refractory
Materials; Carbon Fibers
20040111223 NASA Glenn Research Center, Cleveland, OH, USA
In-Plane Shear Testing of Medium and High Modulus Woven Graphite Fiber Reinforced/Polyimide Composites
Gentz, M.; Armentrout, D.; Rupnowski, P.; Kumosa, L.; Shin, E.; Sutter, J. K.; Kumosa, M.; January 2004; 46 pp.; In English
Contract(s)/Grant(s): F49620-00-1-0159; NSF CMS-99-77735; 708-31-16; Copyright; Avail: CASI; A03, Hardcopy
Iosipescu shear tests were performed at room temperature and at 316 C (600 F) o woven composites with either M40J
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