Solvent-Based Processing of Biomaterials

Several methods that are solvent based will be discussed in this section. In its simplest form, the polymer is dissolved in a suitable solvent called spin dope and extmded through a die called a spinneret (Fig. 3.6). The solvent is then extracted. 

In dry spinning, the solvent evaporation occurs by airflow. In wet spinning, the polymer flber precipitates out in a coagulation bath. Examples of wet spun fibers are Artelon, polyurethanes, polyacrylonitrile. Fibers of diameter 10 -100 pm are typically obtained by the solvent spinning method. 

In gel spinning, a variant of solvent spinning, the polymer is fed as a gel instead of a solution. With gel spinning, very high orientation and strength are possible. The most widely known fiber made by this process is Spectra and Dyneema, both made from ultrahigh molecular weight polyethylene. 

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