Hindawi Publishing Corporation ISRN Polymer Science Volume 2013, Article ID 514617, 8 pages http://dx.doi.org/10.1155/2013/514617 Research Article The Addition of Graphene to Polymer Coatings for Improved Weathering Nurxat Nuraje, 1 Shifath I. Khan, 2 Heath Misak, 2 and Ramazan Asmatulu 2 1 Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA 2 Department of Mechanical Engineering, Wichita State University, 1845 Fairmount, Wichita, KS 67260-0133, USA Correspondence should be addressed to Nurxat Nuraje; nurxat@mit.edu and Ramazan Asmatulu; ramazan.asmatulu@wichita.edu Received 17 July 2013; Accepted 18 August 2013 Academic Editors: W. S. Chow, S. H. Jafari, and J. I. Velasco Copyright © 2013 Nurxat Nuraje et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Graphene nanolakes in diferent weight percentages were added to polyurethane top coatings, and the coatings were evaluated relative to exposure to two diferent experimental conditions: one a QUV accelerated weathering cabinet, while the other a corrosion test carried out in a salt spray chamber. Ater the exposure tests, the surface morphology and chemical structure of the coatings were investigated via atomic force microscopy (AFM) and Fourier transform infrared (FTIR) imaging. Our results show that the addition of graphene does in fact improve the resistance of the coatings against ultraviolet (UV) degradation and corrosion. It is believed that this process will improve the properties of the polyurethane top coating used in many industries against environmental factors. 1. Introduction Polyurethane (PU) is one of the main coatings used in the aircrat and many other industries. PU has important appli- cations in coatings because of its outstanding properties, such as high tensile strength, chemical and weathering resistance, good processability, and mechanical properties [1–3]. How- ever, since PU is an organic coating and subject to deterio- ration, its degradation has been investigated for years [1, 4– 10]. he three critical factors for environmental degradation are ultraviolet (UV) light, water, and oxygen [8, 10–19]. he polymeric material generally degrades when it is exposed to these environmental inluences. UV irradiation irreversibly changes the chemical structure of ilms and thus afects both the physical properties—loss of gloss, yellowing, blistering, cracking, and so forth—and the mechanical properties—loss of tensile strength, brittleness, changes in glass transition temperature (  ), and so forth [1]. In the coating degradation theory [4, 20], the presence of oxygen generates hydrop- eroxides, which in turn accelerates photodegradation of the polyurethane. he presence of water molecules is also another factor accelerating this process. Unsaturated bonds of poly- mers can be activated irst under UV exposure and then react with oxygen to generate carbonyl or peroxide groups. his results in the formation of carbonyl, peroxide, ketone, or aldehyde groups near the coating surface. Weathering degradation of PU can be reduced with the help of novel approaches. An assortment of approaches can be undertaken to pro- tect coatings against weathering conditions and radiation failures [7, 21–26]. To reduce UV degradation, UV screeners [27] are inserted into the bulk polymer. In general, these additives absorb UV light by themselves and minimize the amount of UV light absorbed on the surface of the polymer. UV screeners are high in cost and degrade because of the heavy UV exposure [7, 22, 23, 28]. Applying nanomaterials to coatings, a recent practice for newly developed coating systems, has shown better perfor- mance. Nanomaterials were used to improve the properties of the coating because the nanomaterials have exception- ally high surface area-to-volume ratio which gives rise to exceptional properties in the new products. Since the aspect