Regenerated Cellulose Films with Amino-Terminated Hyperbranched Polyamic Anchored Nanosilver for Active Food Packaging.

The nanosilver-based antibacterial composite film used as food packaging has a potential hazard of silver leakage into the human body. In this study, hyperbranched polyamide-amine (HPAMAM) was used as a template, reducing agent, and stabilizer to synthesize Ag nanoparticles (Ag NPs) in situ, and then HPAMAM anchored Ag NPs onto oxidized cellulose to construct a regenerated cellulose film with a low silver leakage for antibacterial food packaging. Alkali hydroxide/urea solution was used to dissolve cotton fibers, and the hydroxyl groups at C-2 and C-3 of the glucose residues were oxidized to two aldehyde groups by NaIO. Then, HPAMAM/Ag NPs composites (Ag@HPAMAM NPs) were grafted on the oxidized cellulose by the reaction between aldehyde groups and amino groups. The Ag@HPAMAM NPs-embedded cellulose films were achieved by regenerating the dissolved cellulose with ethanol and drying naturally. With a low silver leakage (<10%), Ag@HPAMAM NPs-embedded cellulose films exhibited a strong antibacterial effect on and and effectively extended the storage life of cherry tomatoes as food packaging. In addition, the physical properties of Ag@HPAMAM NPs-embedded cellulose films were improved due to the anchor of Ag NPs onto oxidized cellulose by HPAMAM. This study provides a strategy for synthesizing Ag@HPAMAM NPs-embedded cellulose film, which has the potential to be used as a biodegradable, renewable, and safe antibacterial food package material.