The effects of gamma irradiation on the morphology and properties of polylactide/Cloisite 30B nanocomposites

The oxidative degradation of neat polylactide (PLA) and PLA-Cloisite 30B (DOB) nanocomposites under gamma irradiation was studied for irradiation doses ranging from 0 to 200 kGy. The morphologies and the properties of neat PLA and PLA-C30B nanocomposites (5 wt.%) were investigated using Fourier transform infrared spectroscopy (FT-IR), size exclusion chromatography (SEC), differential scanning calorimetry (DSC), thermogravimetric analysis (ATG), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nanoindentation measurements. The results were analysed by comparing the C30B influence on the PLA degradation. Results show neat PLA is strongly degraded by gamma irradiation while PLA-C30B nanocomposites are less affected because gamma irradiation promotes the DOB layer distribution within the PLA matrix. The morphological defects were much less more pronounced for the PLA nanocomposites compared to neat PLA, for which many voids and cracks were observed after irradiation. (C) 2012 Elsevier Ltd. All rights reserved.