Biodegradation of gamma irradiated poly-3-hydroxybutyrate/sepiolite nanocomposites

The influence of different doses of gamma irradiation on the physical and biodegradation properties of poly-3-hydroxybutyrate/sepiolite (PHB/SP) nanocomposites has been investigated. The sepiolite was modified with vinyltriethoxy silane (VIES) to enhance its compatibility with PHB. The scanning electron micrographs of nanocomposite films showed a good network formation. The infrared spectra of irradiated nanocomposite films indicated a significant decrease in the intensities of peaks observed at 2933 and 2859 cm(-1) (CH stretching vibrations of the vinyl moieties) with an increase in the absorption dose. Thermal stability of nanocomposite films was increased as compared to the PHB. The unirradiated and irradiated nanocomposite films were subjected to in-vitro and soil burial biodegradation studies. Scanning electron micrographs showed the formation of biofilm, agglomerates and pits on the surfaces of nanocomposite films after soil burial. The biodegradation process of nanocomposite films was further confirmed by a sharp reduction in the intensities of IR peaks found at 3658-3045 cm(-1) (OH stretching), 1720 cm(-1) (the carbonyl ester stretching), 1456 cm(-1) (anti-symmetric bending vibration of CH bonds) and 1275 cm(-1) (C-O-C stretching). These results suggest the possible application of the PHB/SP nano composite film as a biodegradable food packaging material. (C) 2017 Elsevier Ltd. All rights reserved.