%0 Journal Article
%T The Addition of Graphene to Polymer Coatings for Improved Weathering
%A Nurxat Nuraje
%A Shifath I. Khan
%A Heath Misak
%A Ramazan Asmatulu
%J ISRN Polymer Science
%D 2013
%R 10.1155/2013/514617
%X Graphene nanoflakes in different weight percentages were added to polyurethane top coatings, and the coatings were evaluated relative to exposure to two different experimental conditions: one a QUV accelerated weathering cabinet, while the other a corrosion test carried out in a salt spray chamber. After 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 aircraft and many other industries. PU has important applications in coatings because of its outstanding properties, such as high tensile strength, chemical and weathering resistance, good processability, and mechanical properties [1¨C3]. However, since PU is an organic coating and subject to deterioration, its degradation has been investigated for years [1, 4¨C10]. The three critical factors for environmental degradation are ultraviolet (UV) light, water, and oxygen [8, 10¨C19]. The polymeric material generally degrades when it is exposed to these environmental influences. UV irradiation irreversibly changes the chemical structure of films and thus affects both the physical properties¡ªloss of gloss, yellowing, blistering, cracking, and so forth¡ªand the mechanical properties¡ªloss 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 hydroperoxides, which in turn accelerates photodegradation of the polyurethane. The presence of water molecules is also another factor accelerating this process. Unsaturated bonds of polymers can be activated first under UV exposure and then react with oxygen to generate carbonyl or peroxide groups. This 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 protect coatings against weathering conditions and radiation failures [7, 21¨C26]. 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
%U http://www.hindawi.com/journals/isrn.polymer.science/2013/514617/