doi:10.1038/nindia.2014.32 Published online 12 March 2014
Researchers have synthesized a nanocomposite film that potentially can be used for wrapping food. They made this nanocomposite film from a cellulose-derived polymer, bacterial cellulose nanocrystals and silver nanoparticles1 .
Previous studies have shown that the cellulose-derived polymer absorbs water, making it unsuitable for protecting food from moisture. In addition, other studies have found that some chemicals in food-packaging materials seep into food.
To develop moisture-resistant films with good mechanical properties, the researchers synthesized the nanocomposite by mixing bacterial cellulose nanocrystals and silver nanoparticles with hydroxylpropyl methyl cellulose, a cellulose-derived polymer. They then produced films of this nanocomposite and probed the mechanical properties of the films.
The researchers observed aggregations of bacterial cellulose nanocrystals; these aggregations formed percolated networks throughout the nanocomposite. This structure enhanced the mechanical properties of the nanocomposite films, including their load-bearing capacity. The silver nanoparticles interacted with the hydroxyl groups of the cellulose-derived polymer, improving the tensile strength and elongation properties of the films. The silver nanoparticles also enhanced the ductility of the films.
Both the bacterial cellulose nanocrystals and the silver nanoparticles reduced the moisture intake of the films through blocking interactions between water molecules and the water-loving polymer.
"These films, which contain two nanomaterials, will be very useful for developing ecofriendly food-packaging materials including potential biomedical applications," says Johnsy George, a co-author of the study.
The authors of this work are from: Defence Food Research Laboratory, Siddarthanagar, and Sri Jayachamarajendra College of Engineering, Mysore, India.