Preparation and Properties of AgNPs Loaded CMC-CMCS Composite Packaging Films with Dual Reduction and Stabilization Functions

Food packaging materials require both antibacterial activity and mechanical strength to ensure food safety. However, conventional synthesis of silver nanoparticles (AgNPs) often involves toxic reagents or leads to particle agglomeration, and composite films usually exhibit insufficient mechanical properties. In this study, carboxymethyl chitosan (CMCS) was used as both a reducing and stabilizing agent to in situ reduce Ag+ under atmospheric-pressure oil-bath heating, yielding CMCS-Ag composites, which were then impregnated into carboxymethyl cellulose (CMC) films to prepare CMC-CMCS-Ag ternary composite packaging films. Under optimal conditions (102 °C, 6 h, 10 mM AgNO3, 0.05% CMCS), AgNPs were uniformly dispersed without aggregation. The tensile strength reached 125.45 MPa, and the inhibition zone diameters against E. coli and S. aureus were 14.1 mm and 14.7 mm, respectively. This work provides a facile strategy for high-performance antibacterial food packaging films.