gelspinning

Gel spinning is a fiber fabrication method used to produce high-strength, high-modulus polymer fibers by processing ultra-high-molecular-weight polymers in a gel-like solution. The technique enables continuous filaments to be drawn and aligned more effectively than in many other spinning methods, making it well suited for extremely long polymer chains.

The most common material is ultra-high-molecular-weight polyethylene (UHMWPE). In gel spinning, UHMWPE is dissolved in a high-boiling solvent, such as decalin, at elevated temperature to form a viscous gel-like solution. This solution is extruded through a spinneret into a non-solvent or cooling bath, where the polymer forms continuous gel fibers. These fibers are then washed and subjected to a controlled drawing or stretching step, often at elevated temperatures, to align the molecular chains, increase crystallinity, and greatly enhance strength and stiffness.

The resulting gel-spun fibers exhibit very high strength-to-weight ratios and strong impact resistance, along with chemical resistance and low density. They are widely used in ballistic armor, protective fabrics, high-performance ropes and cables, fishing lines, and some medical sutures. Gel spinning typically requires careful control of solvent quality, temperature, and draw ratios, and can be more energy-intensive and costly than other spinning processes. Despite these factors, it remains a practical approach for producing some of the strongest commercially available polymer fibers.