An Attempt to Characterize and Elaborate Anisotropic Pitches and Derived Carbon Fibers, Part I: Preparation by Bubbling
Gas-sparge process was approximated by bubbling. Heterogeneous anisotropic pitch was prepared by pulsing bubbles of nitrogen in an isotropic pitch Kraemer-Sarnov point (KS 70°C) thermally evolving (irregular bubbling). It was compared to laboratory and industrial, B, B1, … B3 pitches. All of them are mixtures of isotropic phase 1 containing Brooks and Taylor mesophase spheres with an edge-to-edge type of gel 2–3. The latter is a two-phase disperse system made of a major anisotropic component 2 including orthogonally oriented microdroplets 3. The gel 2–3 is quinoline-soluble but toluene insoluble (QS.TI) (i.e., β resins). From B, B1 to B3, the amount of phase 1 increases and becomes the major component in B2 and B3. A more steady stirring yields a pitch C1 free of isotropic phase 1 and identical to the industrial pitch C. Heterogeneous pitches yield poor heterogeneous fibers. The pure gel 2–3 pitch yields improved fibres. After graphitization, the cross sections are entirely full of nano zig-zag issued from 2–3. The larger the grains, forming (in projection) the linear parts of the zig-zag, the better the graphitizability.
Copyright © 1994, Elsevier
Lafdi, Khalid and Oberlin, Agnès, "An Attempt to Characterize and Elaborate Anisotropic Pitches and Derived Carbon Fibers, Part I: Preparation by Bubbling" (1994). Chemical and Materials Engineering Faculty Publications. 81.