Mesoscale Modeling of Solvent Evaporation from the Surface of a Jet of Spinning Solution of Polyacrylonitrile in Dimethyl Sulfoxide

This work discusses a mesoscale computer model based on the dissipative particle dynamics method. The model is aimed at studying the processes occurring at the initial stage of forming polyacrylonitrile-based chemical fibers by dry-jet wet spinning method. The model represents the appearance of structural inhomogeneities on the surface of a polymer solution jet as it passes through the air gap between the spinneret and the coagulation bath. According to the calculation results, a high-density polymer layer appears on the surface of the forming fiber the as a result of solvent evaporation, and this layer can significantly affect the polymer′s coagulation rate. The estimations of the layer thickness show that a ~0.5 µm thick layer is sufficient for making the spinning solution jet maintain in air for ~0.6 s. The obtained results can be useful in tuning the technological process of dry-jet wet method of chemical fiber spinning.