Please cite this article in press as: M. Sangermano, et al., Improvement of the water-vapor barrier properties of an uv-cured epoxy coating containing graphite oxide nanoplatelets, Prog. Org. Coat. (2016), http://dx.doi.org/10.1016/j.porgcoat.2016.10.032 ARTICLE IN PRESS G Model POC-4126; No. of Pages 4 Progress in Organic Coatings xxx (2016) xxx–xxx Contents lists available at ScienceDirect Progress in Organic Coatings journal homepage: www.elsevier.com/locate/porgcoat Improvement of the water-vapor barrier properties of an uv-cured epoxy coating containing graphite oxide nanoplatelets M. Sangermano a,∗ , M. Periolatto b , V. Signore a , P. Russo Spena b a Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino, Italy b Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano, Italy a r t i c l e i n f o Article history: Received 15 April 2016 Received in revised form 28 June 2016 Accepted 21 October 2016 Available online xxx Keywords: Barrier properties Water vapor diffusion Epoxy resin Cationic UV-curing a b s t r a c t In this paper we investigated the improvement of water-vapor barrier properties of an UV-cured epoxy film containing graphite oxide nanoplatelets. Graphene platelets were successfully dispersed in the epoxy resin and cured by UV-irradiation. Good performances in increasing water vapor barrier properties at a very low filler loading are obtained: the permeability decreased of about 40% with a 0.5 wt.% of GOx and of about 60% with a 1.0 wt.% of GOx. These good results are attributed to a homogeneous filler dispersion, as clearly shown by TEM microscopy. © 2016 Elsevier B.V. All rights reserved. 1. Introduction Polymeric films are largely used in the packaging and coating industry with the stringent requirement of high oxygen and water vapor barrier properties. Because of their relatively high perme- ability for gases or water vapor, pristine polymers are not suitable materials for these purposes. Industrial applicants cope with this problem by using laminated films, which consist of many compo- nents such as functional polymers (mainly silanes or fluorinated compounds) and aluminum foils [1]. Among the different strate- gies suggested in the literature, the preparation of nanocomposite materials is one of the most promising methods for improving gas barrier properties [2,3]. Polymer/clay nanocomposites represent an effective strategy to decrease gas permeability [4–6]. In particular, the presence of the layered clay fillers can induce a significant decrease in both oxygen and moisture permeability. A strong reduction in oxygen permeability upon the incorporation of organoclay into PE was reported by Osman et al. [7,8]. Avella et al. suggested that the intro- duction of calcium carbonate nanoparticles drastically reduced the permeability of oxygen and carbon dioxide for polypropylene nanocomposites [9]. Similar results were also achieved by dispers- ing clays in thermosets [10] and in vulcanized rubbers [11]. The incorporation of fillers in platelet shape generates a structure able ∗ Corresponding author. E-mail address: marco.sangermano@polito.it (M. Sangermano). to hinder penetrant diffusion and thus decrease the permeability of the material [12]. In this case, the tortuous diffusion path model may be applied to the composite. More recently, graphene and its derivative nanosheets have been considered as potential fillers for gas barrier membranes due to their diffusion hindering effect [13–18]. Therefore, lamel- lar structure of graphene are an interesting alternative to the use of organoclays fillers to enhance the gas barrier properties of poly- meric matrices. In this context, Vitale et al. investigated the effect on water vapor barrier properties of graphene nanoplatelets in an UV-curable perfluoropolyether methacrylic oligomer. They found an increase of the water vapor barrier properties of this polymer at very low filler amounts [19]. The present study focuses on the improvement of the water vapor barrier properties of an UV-cured cycloaliphatic epoxy matrix containing graphene oxide nanoplatelets. The choice of the filler is related to its lamellar morphology which could generate a tortuous diffusion path able to hinder penetrant diffusion and thus decrease the gas permeability of the material. In particular, the tortuous path induced by the graphene sheets should act on the kinetic of the water vapor diffusion through the polymeric films, thereby improving its barrier behavior. Furthermore, the graphite oxide shows a good compatibility with the epoxy resin due to the presence of the polar functional groups on its surface. http://dx.doi.org/10.1016/j.porgcoat.2016.10.032 0300-9440/© 2016 Elsevier B.V. All rights reserved.