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Transparent Pullulan/Mica Nanocomposite Coatings with Outstanding Oxygen Barrier Properties

DeFENS, Department of Food, Environmental and Nutritional Sciences—Packaging Division, University of Milan, via Celoria, 2, 20133 Milan, Italy
Department of Food Engineering, Faculty of Engineering, İzmir University of Economics, İzmir 35330, Turkey
School of Packaging, Michigan State University, East Lansing, MI 48824, USA
Department of Food Engineering, Izmir Institute of Technology, İzmir 35430, Turkey
Department of Materials Science, University of Milano Bicocca, via Cozzi 55, 20125 Milan, Italy
INSTM, National Consortium of Materials Science and Technology, Local Unit University of Milan, via Celoria 2, 20133 Milan, Italy
Authors to whom correspondence should be addressed.
Nanomaterials 2017, 7(9), 281;
Received: 31 August 2017 / Revised: 14 September 2017 / Accepted: 15 September 2017 / Published: 19 September 2017
(This article belongs to the Special Issue Polymer Nanocomposites)
This study presents a new bionanocomposite coating on poly(ethylene terephthalate) (PET) made of pullulan and synthetic mica. Mica nanolayers have a very high aspect ratio (α), at levels much greater than that of conventional exfoliated clay layers (e.g., montmorillonite). A very small amount of mica (0.02 wt %, which is ϕ ≈ 0.00008) in pullulan coatings dramatically improved the oxygen barrier performance of the nanocomposite films under dry conditions, however, this performance was partly lost as the environmental relative humidity (RH) increased. This outcome was explained in terms of the perturbation of the spatial ordering of mica sheets within the main pullulan phase, because of RH fluctuations. This was confirmed by modelling of the experimental oxygen transmission rate (OTR) data according to Cussler’s model. The presence of the synthetic nanobuilding block (NBB) led to a decrease in both static and kinetic coefficients of friction, compared with neat PET (≈12% and 23%, respectively) and PET coated with unloaded pullulan (≈26% reduction in both coefficients). In spite of the presence of the filler, all of the coating formulations did not significantly impair the overall optical properties of the final material, which exhibited haze values below 3% and transmittance above 85%. The only exception to this was represented by the formulation with the highest loading of mica (1.5 wt %, which is ϕ ≈ 0.01). These findings revealed, for the first time, the potential of the NBB mica to produce nanocomposite coatings in combination with biopolymers for the generation of new functional features, such as transparent high oxygen barrier materials. View Full-Text
Keywords: coefficient of friction; haze; mica; modelling; optical properties; oxygen barrier; pullulan coefficient of friction; haze; mica; modelling; optical properties; oxygen barrier; pullulan
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MDPI and ACS Style

Uysal Unalan, I.; Boyacı, D.; Trabattoni, S.; Tavazzi, S.; Farris, S. Transparent Pullulan/Mica Nanocomposite Coatings with Outstanding Oxygen Barrier Properties. Nanomaterials 2017, 7, 281.

AMA Style

Uysal Unalan I, Boyacı D, Trabattoni S, Tavazzi S, Farris S. Transparent Pullulan/Mica Nanocomposite Coatings with Outstanding Oxygen Barrier Properties. Nanomaterials. 2017; 7(9):281.

Chicago/Turabian Style

Uysal Unalan, Ilke, Derya Boyacı, Silvia Trabattoni, Silvia Tavazzi, and Stefano Farris. 2017. "Transparent Pullulan/Mica Nanocomposite Coatings with Outstanding Oxygen Barrier Properties" Nanomaterials 7, no. 9: 281.

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