Graphite Fibers from Pitch
Final rept. Feb 1974-Mar 1975
UNION CARBIDE CORP CLEVELAND OH CARBON PRODUCTS DIV
Pagination or Media Count:
The properties of the multifilament yarn improved over those achieved in the past. Strand tensile strength of up to 2.30 GPa approx. 350 Kpsi was measured on fibers with an elastic modulus of 200 GPa approx. 30 Mpsi. Tests on flat plate composites with epoxy indicated good translation of properties if corrections were made for insufficient fiber loading. The absolute tensile strength of the thin monofilament did not exceed the levels reported in the previous report, but reliable average values in excess of 3.45 GPa approx. 500 Kpsi were obtained on filaments with elastic moduli of 300 GPA 45 Mpsi. Attempts to further improve fiber properties by modified thermosetting methods or by processing with tension were not fruitful. Many structural features of the filaments were observed in SEM after etching the fibers in hot air. The monofilament, with random or onion-skin structure, was in most respects similar to Thornel 300 fibers. The filaments with radial structure, found in the multifilament yarn, appeared to contain between the oriented ribbons a carbon phase which was considerably more susceptible to oxidation than the ribbons themselves. So far, only gas bubbles and some surface flaws have been identified as major structural defects in Type-P fibers.
- Refractory Fibers
- Laminates and Composite Materials
- Miscellaneous Materials