Abstract
The fiber forming process of nylon 3 in the wet spinning process was investigated, using formic acid as the solvent and alcohols, esters and ethers as the coagulants. Following results were obtained:
As for the mass transportation in the wet spinning of nylon 3, the solvent (formic acid) diffuses into the coagulant while the coagulant does not permeate into proto-fibers. Thus homogeneously deswelled proto-fibers were obtained.
The maximum draft ratio is mainly affected by three factors, that is to say, coagulation power of a coagulant, molecular weight of the polymer and polymer concentration of the spinning dope. The highest value of the maximum draft ratio is attained in a definite range of the coagulation power of coagulants. By decreasing polymer concentration and molecular weight of the polymer the maximum draft ratio is increased.
Cross sectional shapes of the proto-fibers are mainly affected by coagulation power of the coagulants. When coagulation power is strong, the cross sectional shape of the fibers is changed and when coagulatian power is weak, the cross sections of the fiber were dog-bone-shaped.
As proto-fibers are already crystallized, it is not possible to orientate the prato-fibers by drawing in a coagulation bath.
