Effects of Formation Conditions on Morphology and Properties of Polyacrylonitrile Fibers in Dry-jet Wet Spinning Process

Polyacrylonitrile fibers were prepared by dry-jet wet spinning process. The effects of formation conditions, including coagulation medium, coagulation conditions, and draw conditions, were investigated in detail. Using mixture of water and DMSO as the coagulation medium, PAN fibers with compact microstructure can be obtained by adopting low coagulation temperature as well as gradient coagulation process. Using ethanol instead of water as the nonsolvent for the coagulation medium, PAN fibers with compact microstructure can be prepared at a lower DMSO concentration of the coagulation medium. Also, the cross-section shape of the fiber varied with the composition of the coagulation medium. Finally, mechanical properties of the fibers could be enhanced greatly via additional drawing in air before the commonly-used two-stage drawing treatment.