Carboxymethyl Chitosan‐based Biodegradable Films Preparation and Prospects for Food Preservation

Abstract In this study, carboxymethyl chitosan (CMCS)‐based biodegradable films were prepared by blending with polyvinyl alcohol (PVA) in water and characterized for their potential application as innovative food packaging materials. Blends of CMCS and PVA polymer solutions were cast and dried at 50 °C for 48 hours to obtain a flexible and transparent film. The films were prepared at different composition and were characterized using various techniques including Fourier‐transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), tensile strength (TS), scanning electron microscopy (SEM), and Thermogravimetric analysis (TG). The FTIR analysis confirmed the successful incorporation of carboxymethyl groups into the chitosan molecules, indicating the modification of chitosan. XRD pattern indicates an amorphous phase of the CMCS films. SEM images of the film surfaces show a uniform structure containing no cracks or holes revealing that both PVA and CMCS had good compatibility and unique film‐forming ability. The CMCS/PVA films demonstrated superior performance compared to conventional synthetic packaging materials, with a low water vapor transmission rate (53.46 g/m 2 /h), good tensile strength (10.8 MPa), and elongation at break (20.36%). Practical application tests showed that coating green chilies with CMCS/PVA films reduced water loss by 20% compared to uncoated chilies, effectively enhancing their shelf life.