The steady and transient rheological behavior or mesophase pitches

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:602944

Fleurot, O; Edie, D D ^[1]

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1. Clemson Univ., SC (United States)

Carbonaceous mesophase, a discotic, nematic liquid crystal, is a common precursor for the production of high performance (high thermal conductivity) carbon fibers. During melt spinning of mesophase pitches into fiber form, the poly-domain structure is stretched and oriented. A highly-oriented as-spun structure can be readily graphitized, giving the final heat-treated fiber superior thermal properties. Obviously, understanding, predicting, and ultimately controlling the development of structure is critical, if the final properties of mesophase pitch carbon fibers are to be optimized. While the development of structure in mesophase has been qualitatively described, quantitative information is needed. Complicating factors are: (i) the physical properties of mesophase pitches depend on the nature of the precursor material used to produce the liquid crystalline fluid, (ii) the rheological properties of mesophase are highly temperature-dependent, and (iii) mesophase pitch is optically opaque. In this work, the development of structure during steady and transient flow was investigated for different mesophase pitches.

• OSTI ID: 602944
• Report Number(s): CONF-961108--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON FIBERS
DOMAIN STRUCTURE
HEAT
PHYSICAL PROPERTIES
THERMAL CONDUCTIVITY