Graphene Oxide Bionanocomposite Coatings with High Oxygen Barrier Properties.
In this work, we present the development of bionanocomposite coatings on poly(ethylene terephthalate) (PET) with outstanding oxygen barrier properties. Pullulan and graphene oxide (GO) were used as main polymer phase and nanobuilding block (NBB), respectively. The oxygen barrier performance was investigated at different filler volume fractions (ϕ) and as a function of different relative humidity (RH) values. Noticeably, the impermeable nature of GO was reflected under dry conditions, in which an oxygen transmission rate (OTR, mL·m-2·24 h-1) value below the detection limit of the instrument (0.01 mL·m-2·24 h-1) was recorded, even for ϕ as low as 0.0004. A dramatic increase of theOTRvalues occurred in humid conditions, such that the barrier performance was totally lost at 90% RH (theOTRof coated PET films was equal to theOTRof bare PET films). Modelling of the experimentalOTRdata by Cussler's model suggested that the spatial ordering of GO sheets within the main pullulan phase was perturbed because of RH fluctuations. In spite of the presence of the filler, all the formulations allowed the obtainment of final materials with haze values below 3%, the only exception being the formulation with the highest loading of GO (ϕ ≈ 0.03). The mechanisms underlying the experimental observations are discussed.
DeFENS, Department of Food, Environmental and Nutritional Sciences-Packaging Division, University of Milan, via Celoria 2-20133 Milan, Italy. iuysalunalan@gmail.com.|Department of Food Engineering, Faculty of Engineering, İzmir University of Economics, İzmir 35330, Turkey. iuysalunalan@gmail.com.|School of Packaging, Michigan State University, East Lansing, MI 48824, USA. iuysalunalan@gmail.com.
Ilke
I
Uysal Unalan
DeFENS, Department of Food, Environmental and Nutritional Sciences-Packaging Division, University of Milan, via Celoria 2-20133 Milan, Italy. uysaluna@msu.edu.|Department of Food Engineering, Izmir Institute of Technology, İzmir 35430, Turkey. uysaluna@msu.edu.
Derya
D
Boyacı
DeFENS, Department of Food, Environmental and Nutritional Sciences-Packaging Division, University of Milan, via Celoria 2-20133 Milan, Italy. boyaci.derya@gmail.com.
Masoud
M
Ghaani
Department of Materials Science, University of Milano Bicocca, via Cozzi 55-20125 Milan, Italy. silvia.trabattoni@mater.unimib.it.
Silvia
S
Trabattoni
DeFENS, Department of Food, Environmental and Nutritional Sciences-Packaging Division, University of Milan, via Celoria 2-20133 Milan, Italy. stefano.farris@unimi.it.|INSTM, National Consortium of Materials Science and Technology, Local Unit University of Milan, via Celoria 2-20133 Milan, Italy. stefano.farris@unimi.it.
Stefano
S
Farris
graphene oxide; haze; modelling; oxygen transmission rate; pullulan; relative humidity