Preparation of chitosan filament applying new coagulation system

A new coagulation system for chitosan, aqueous alcohol solution of calcium chloride or acetate, was found and successfully applied for spinning of chitosan filament. FT-IR and atomic absorption spectrophotometric experiments indicated that chitosan coagulation was induced through calcium chelation with amino group of chitosan molecule. The original spun filament was soluble in water because chitosan exists as an acetic acid salt form. Among several treatments, diluted sodium hydroxide aqueous solution eliminated acetate as well as calcium ion. Obtained filament showed excellent properties. The present coagulation system, essentially a mild and safe has an advantage over the conventional hazardous system which were based on the copper ammonium or xanthate systems.