Effect of electron beam irradiation on the properties of polylactic acid/montmorillonite nanocomposites for food packaging applications

This study was aimed at (1) developing new films based on polylactic acid/montmorillonite (PLA/MMT) with improved properties for applications in the food packaging industry and (2) analyzing the effect of electron-beam (eBeam) radiation on the structural, morphological, mechanical, and barrier properties of these nanomaterials. Nanocomposites based on PLA with 1, 3, and 5 wt % of MMT were prepared in a twin-screw extruder and then filmed by a calender. The nanocomposites were exposed to eBeam doses; one set at 1 kGy dose and the other at 10 kGy dose. The effect of MMT addition and of eBeam radiation on the properties of PLA were assessed. For all composites, a homogeneous distribution and dispersion of MMT in the PLA matrix was obtained. All nanocomposites showed an increase of the mechanical and oxygen-barrier properties compared to neat PLA. The eBeam irradiation caused an increase of the crystallinity, formation of crosslink, increase of the glass-transition temperatures, and enhancement of the yield values in the stress-strain curves for all nanocomposites. This study demonstrated that PLA/MMT films are suitable materials for eBeam processing of prepacked food at the realistic doses that were employed in this study. (C) 2015 Wiley Periodicals, Inc.