Continuous Pilot-Scale Wet-Spinning of Biocompatible Chitin/Chitosan Multifilaments from an Aqueous KOH/Urea Solution

Chitin is a promising natural polymer with great potential as a biomedical, hygiene, absorbent, and food-packing material. Producing chitin multifilament and assembling them into textiles is an efficient way of preparing these materials, with wet-spinning a major method used to produce man-made fibers. Unfortunately, dissolving chitin, producing a stable and suitable chitin dope, and ensuring filament strength are the main obstacles to the production of chitin multifilament. Based on recent research into chitin dissolution, solution properties, and high-strength chitin-based materials, chitin multifilament wet-spinning is no longer only a hypothetical strategy. Here, a pilot-scale wet-spinning method is introduced that overcomes the abovementioned limitations. A stable chitin spinning dope is prepared by dissolution and aging in an aqueous KOH/urea solution. A chitin multifilament is prepared by wet-spinning using a pilot-scale wet-spinning apparatus and aqueous alcohol/salt coagulation. After deacetylation, the chitosan multifilament possesses a dense structure and low crystallinity, but excellent mechanical properties. The chitin/chitosan multifilaments exhibit excellent cytocompatibilities and have promising prospects in biomedical applications. The method developed in this work provides a new approach for the pilot-scale wet-spinning of chitin/chitosan multifilaments.