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Properties of hybrid CVD/PAN graphite fibers and their bromine intercalation compoundsA hybrid fiber with a PAN core surrounded by a vapor grown carbon fiber (VGCF) sheath was fabricated using a proprietary process. The density, ultimate tensile strength, Young's modulus, and resistivity of pristine and bromine intercalated fibers made by this technique having diameters varying from 5 to 50 microns were compared with the values predicted from the rule of mixtures model. For both the pristine and intercalated fibers, the density, ultimate tensile strength, and Young's modulus of the fibers were lower than predicted, but the resistivity was measured to be consistent with predictions. The lower than theoretical mechanical properties may be evidence of a low density disordered interface between the core and the sheath which would lower the density and degrade the mechanical properties, but would leave the resistivity nearly unaffected. Intercalation had little if any effect on the ultimate tensile strength and Young's modulus, but raised the density by about 11 pct., and lowered the resistivity by an order of magnitude. The diameter dependence of the resistivity showed evidence of a depletion layer of the type found in VGCF.
Document ID
19930033678
Document Type
Reprint (Version printed in journal)
Authors
Gaier, James R. (NASA Lewis Research Center Cleveland, OH, United States)
Lake, Max L. (Applied Sciences, Inc. Yellow Springs, OH, United States)
Moinuddin, Alia (NASA Lewis Research Center Cleveland, OH, United States)
Marabito, Mark (Cleveland State Univ. OH, United States)
Date Acquired
August 15, 2013
Publication Date
January 1, 1992
Publication Information
Publication: Carbon
Volume: 30
Issue: 3
ISSN: 0008-6223
Subject Category
COMPOSITE MATERIALS
Funding Number(s)
PROJECT: RTOP 506-41-41
Distribution Limits
Public
Copyright
Other