Starch/silver nanocomposite: Effect of thermal treatment temperature on the morphology, oxygen and water transport properties

The present work reports a strategy involving the preparation of nanostructured starch based film containing silver nanoparticles (AgNPs) using a completely green chemistry process. The nanocomposite films were prepared by solution cast process. The AgNPs were in situ generated inside the polymer film by thermal treatment at different temperatures (25, 40 and 85 °C). The influence of the presence and the amount of reducing agent (glucose) were also investigated. For all nanocomposite films, the AgNPs were spherical with a diameter less than 15 nm. Contrary to the presence of glucose, thermal treatment condition was a key factor for the AgNPs structure. Crystalline AgNPs were obtained only after thermal treatment at 85 °C. Improvements of water and oxygen barrier properties near to one decade were observed in this last case and were explained by the formation of crystalline AgNPs associated to the establishment of strong interactions between AgNPs and starch polymer matrix.