Fundamental analysis of the dynamics, mass transfer, and coagulation in wet spinning of fibers

New models are developed to analyze the wet spinning process. These involve a formulation of simultaneous overall mass, force, and solvent mass transfer balances. In the first‐order model, internal concentration gradients and mass transfer resistance within the fiber are neglected. It is equivalent to the Kase–Matsuo melt spinning model. In the second‐order model, concentration gradients and diffusion within the fiber are included. Comparison is made with an experimental study of wet spinning nylon‐66 fibers. The first‐order model seriously underpredicts final fiber diameter under conditions of specified spinline tension and spinning efflux. The second‐order model gives better agreement between theory and experiment.