Pitches pretreatment processes

During the ensuing five years, a number of pitches were developed as carbon fiber precursors through use of various pretreatment techniques (4-9). We explored four basic pretreatment processes, sometimes in combination (a) polymerization and/or... 

Based on the creation of naphthenic structures in the condensation reaction, the modification by aluminum chloride increased carbon yield and improved the potential for anisotropic development. Oxidative pretreatment usually impairs anisotropic development although it increases carbon yield. The oxidized pitch is also modified by aluminum chloride (34) this may be used to prepare additives (38) and mesophase pitches (39). It should be noted that these processes allow the catalyst to be readily separated (in contrast to catalytic carbonization) since the modified product is still either soluble in some solvents or fusible. 

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