Biodegradable nanocomposite blown films based on poly(lactic acid) containing silver-loaded kaolinite: A route to controlling moisture barrier property and silver ion release with a prediction of extended shelf life of dried longan

Novel biodegradable nanocomposite blown films based on compatibilized poly(lactic acid)-poly(-butylene adipate-co-terephthalate) blend are fabricated for use as a model package for dried longan. Silver-loaded kaolinite (AgKT) dispersing in the polymer matrix in intercalated-exfoliated fashion functions as an excellent property improver of the blend. The emphasis of this paper is enhancement of film moisture barrier property by inducing polymer crystallization coupled with formation of AgKT tortuous path. Additionally, controlled silver release which provides long-term antibacterial activity is attributed to AgKT's layered structure. The amount of released silver ions herein also complies with migration levels specified by the standard for food-contact plastic packages. Dried longan shelf lives as eventually predicted by experimental moisture sorption isotherm and by Peleg model are almost identical (similar to 308 days) for the nanocomposite films being over two folds of that obtained from the compatibilized blend package at ambient condition. (C) 2014 Elsevier Ltd. All rights reserved.