IMPROVEMENTS IN THE DRYING PROCESS FOR WET-SPUN CHITOSAN FIBERS

Chitosan fibers were wet spun from a 6% by weight chitosan in 3% by vo lume acetic acid solution. The fibers were collected as a 20 filament yarn intended for use as a chaff substrate. The yarn had to be suffici ently dry following spinning to allow for winding and subsequent separ ation of the filaments. Drying of the yam was attempted using various techniques including direct and radiant heat, forced air, and chemical drying agents. Product yarns were analyzed for ease of separation of the filaments, as well as comparison of mechanical properties. Individ ual fibers were evaluated on the basis of moisture content, surface mo rphology and fiber diameter. Results indicate that the particular dryi ng method or agent used has a considerable impact upon all of the char acteristics listed above. A methanol dry bath was found to provide opt imum drying of the chitosan yam, producing filaments with low moisture content that separated easily from one another. Methanol drying yield ed chitosan fibers with smaller diameter, superior surface smoothness and superior mechanical properties to fibers dried using forced air, h eat, or other tested drying agents such as acetone and isopropanol. (C ) 1998 John Wiley & Sons, Inc.