- Gel spinning is a special process used to obtain high strength
or other special fiber properties. The polymer is not in a true liquid
state during extrusion. Not completely separated, as they would be in a
true solution, the polymer chains are bound together at various points
in liquid crystal form.
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- This produces strong inter-chain forces
in the resulting filaments that can significantly increase the tensile
strength of the fibers. In addition, the liquid crystals are aligned
along the fiber axis by the shear forces during extrusion. The filaments
emerge with an unusually high degree of orientation relative to each
other, further enhancing strength. The process can also be described as
dry-wet spinning, since the filaments first pass through air and then
are cooled further in a liquid bath. Some high-strength polyethylene and
aramid fibers are produced by gel spinning.