Liquid handling properties of carboxymethyl modified chitosan nonwovens for medical dressings

Chitosan (CS) is known to have excellent antibacterial, anti-inflammatory and hemostatic properties, while its liquid handling performances are dissatisfactory, making it hard to maintain a moist environment as wound dressings. In this study, the carboxymethyl chitosan (CMCS) needle-punched nonwovens were prepared by chloroacetic acid method. The structure and properties of CS and CMCS nonwovens were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), mass per unit area and thickness. Moreover, the liquid handling properties, including liquid absorption, retention, diffusion and contact angle were further investigated. The optimal parameters for carboxymethyl modification were explored via orthogonal experiments. Results demonstrated that CMCS nonwovens were successfully prepared, and the optimal conditions for carboxymethyl reaction were NaOH concentration of 30 %, NaOH to chloroacetic acid molar ratio of 5:1, and etherification time of 4 h. The liquid absorption, retention, diffusion and hydrophilic properties of CMCS nonwovens were evidently enhanced compared with pristine CS nonwovens. Owing to the outstanding liquid handling properties, the proposed CMCS nonwovens might have potential application as medical dressings.