Chitosan/gallnut tannins composite fiber with improved tensile, antibacterial and fluorescence properties.

Natural extracts gallnut tannins (GTs) were used as functional components to prepare chitosan/gallnut tannins (CS/GTs) composite fiber by blended solution spinning. Chitosan fiber has great potential to be used as absorbent suture and dressing due to its good biocompatibility. However, the weak mechanical properties limited its application. Chitosan and GTs were blended in aqueous solution of acetic acid to spin the composite fiber. The results indicated that CS/GTs fiber can be easily prepared due to the appropriate rheology characteristics for blended solution. Compared with pure chitosan fiber, CS/GTs fiber with 10% GTs showed lower hydrophilicity and higher dry, wet breaking strength by more than 40% due to ionic cross-linking between chitosan and GTs. The bacterial reduction to Staphylococcus aureus increased from 49.0 to 99.7% and about double green and red fluorescent intensity were observed for CS/GTs fiber. GTs have great potentiality in improving the properties of chitosan fiber.