Factors affecting wet spinning

The wet spinning process consists of preparation of the polymer solution, extrusion of polymer solution into a liquid bath, coagulation in this bath and further processes applied to the spun fibers. Polymer concentration in the dope depends mainly on polymer solubility and spinning pressure limitations. The fiber formation in the coagulation bath is a complex process and it involves parameters of bath composition, temperature, extrusion and take-up velocity. 

Mass transfer rate difference is among the most important factors in the coagulation of the outer layer of the dope, and is determinative in the resultant properties and microstructure of the as-spun fibers. 

Mass transfer in wet spinning has been studied extensively in the hter-ature. Rende built a physiochemical model to understand the relationship between coagulation of polyacrylonitrile and the coagulation bath variables. The model shows that polymer is precipitated at a distance from the fiber axis that varies with time.  

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