Mesophase Behavior in Carbon Fiber Bundles.
AEROSPACE CORP EL SEGUNDO CA MATERIALS SCIENCES LAB
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Some experimental procedures required to observe the development of mesophase morphologies in three-dimensional carbon-carbon composites during pyrolysis at high pressures have been tested in preliminary room-pressure trials. Bundles of mesophase carbon fiber in petroleum pitch were pyrolyzed under three conditions of constraint. The results confirm a recent report that the mesophase transformation proceeds differently within a fiber bundle than in bulk pitch. In the early stages of transformation, both pitch and mesophase wet the fiber, and the mesophase tends to occur preferentially within the open wedge of radially structured fiber. After pyrolysis through the stage of mesophase hardening, the matrix porosity appears to depend on the constraint of the fiber bundle. The mesophase at that stage is a fragile solid easily fractured by local stresses within the fiber bundle. Author
- Laminates and Composite Materials