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The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile (PAN) wet-spinning and the effect of coagulation bath conditions on the structure and properties of the nascent fibers were investigated by the means of X-ray diffraction (XRD), scanning electron microscope (SEM), fiber fineness machine, fiber tensile strength machine, etc. The experimental results indicate that the nascent fibers become denser and have fewer inner defects, the diameter of nascent fibers shrink and the crystallization degree of nascent fibers gradually increases with the increasing of coagulation time. Too large spinning tension leads to grooves occurring on surface of fibers. To obtain circular cross-section of nascent fibers the optimal coagulation conditions are 50 ℃, 65% (concentration) and 0.9 (draw ratio).
The evolvement of microstructure and properties of nascent fibers during coagulation process in the polyacrylonitrile (PAN) wet-spinning and the effect of coagulation bath conditions on the structure and properties of the nascent fibers were investigated by the means of X-ray diffraction (XRD) , scanning electron microscope (SEM), fiber fineness machine, fiber tensile strength machine, etc. The experimental results that that nascent fibers become denser and have fewer inner defects, the diameter of nascent fibers shrink and the crystallization degree of nascent fibers with the increasing of coagulation time. To obtain circular cross-section of nascent fibers the optimal coagulation conditions are 50 ° C, 65% concentration and 0.9 (draw ratio).