Effect of additives on the cross section of PAN fibers

Abstract

Additives are generally added to spin dope in wet spinning to facilitate mechanical operations, increase solid content, and effect gelation to precede phase separation. Besides these advantages, they have an effect on the cross section of PAN fibers. Organic compounds (hydrochlorides of aryl, alkyl secondary amines, etc.) change the cross section to a bean shape, whereas a nonsolvent (water) and inorganic compounds (calcium salts, borax, boric acid, etc.) retain the circular cross section of PAN fibers. The change in cross section can be attributed to the change in skin and core effects at different pH values of the spin dope in the presence of the additives.