Water Transport in Polylactide and Polylactide/Montmorillonite Composites
Polylactide–montmorillonite composites were fabricated by melt-blending followed by compression molding, and water permeability of the composites was studied by both experiments and theoretical models. The water permeation in composites decreases with increasing concentration of montmorillonite. Specifically, at a concentration of 10 wt% of montmorillonite, the water permeation is 34 % less than in the neat polymer. Transmission electron microscopy (TEM) and wide-angle X-ray scattering (WAXS) results show that most of the montmorillonite particles are well-dispersed and randomly exfoliated in the polymer matrix. A fit of theoretical models to the permeation data estimates that montmorillonite platelets are mostly exfoliated in the polymer matrix and oriented randomly, which matches with results from WAXS and TEM.
KeywordsExfoliation Montmorillonite Permeation Polylactide
This research was supported by USDA Biomass Research and Development Initiative, funding number DE-PS36-06GO96002P. Commercial PLA samples were provided by NatureWorks, LLC and organically modified clay (montmorillonite) was provided by Southern Clay Product, Inc. Access to experimental instruments in the laboratory of Giuseppe Palmese (Chemical and Biological Eng), Christopher Li (Materials Sci. and Eng) and the Drexel Centralized Research Facility is acknowledged. Thanks to Fatima Nia Roodsari (Polymer Processing Group, University of Calgary) for mixing and compression molding experiments. Discussions with Marc Hillmyer (U. Minnesota, Chemistry Dept.), Shri Ramaswamy (U. Minnesota, Bio-based products Dept.) and Yossef Elabd (Chemical Eng.) were also helpful for this research.
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