Custom-Made Chemically Modified Graphene Oxide to Improve the Anti-Scratch Resistance of Urethane-Acrylate Transparent Coatings

In this work, a thermoset ultraviolet (UV)-cured polyurethane-acrylate resin was doped with different chemically-modified graphene obtained from a commercial graphene oxide (GO): as-received GO, chemically reduced GO (rGO), GO functionalized with vinyltriethoxysilane (VTES) (GOvtes), and GO functionalized with VTES and subsequently reduced with a chemical agent (rGOvtes). Modified graphene was introduced in the oligomer component via solvent-assisted process using acetone, which was recovered after completion of the process. Results indicate that the GO-doped oligomers produce cured coatings with improved anti-scratch resistance (above the resistance of conventional coatings), without surface defects and high transparency. The anti-scratch resistance was measured with atomic force microscopy (AFM). Additionally, results are presented in terms of Wolf–Wilburn scale, a straightforward method widely accepted and employed in the coating industry.

Detection and Quantification of Graphene-Family Nanomaterials in the Environment

An increase in production of commercial products containing graphene-family nanomaterials (GFNs) has led to concern over their release into the environment. The fate and potential ecotoxicological effects of GFNs in the environment are currently unclear, partially due to the limited analytical methods for GFN measurements. In this review, the unique properties of GFNs that are useful for their detection and quantification are discussed. The capacity of several classes of techniques to identify and/or quantify GFNs in different environmental matrices (water, soil, sediment, and organisms), after environmental transformations, and after release from a polymer matrix of a product is evaluated. Extraction and strategies to combine methods for more accurate discrimination of GFNs from environmental interferences as well as from other carbonaceous nanomaterials are recommended. Overall, a comprehensive review of the techniques available to detect and quantify GFNs are systematically presented to inform the state of the science, guide researchers in their selection of the best technique for the system under investigation, and enable further development of GFN metrology in environmental matrices. Two case studies are described to provide practical examples of choosing which techniques to utilize for detection or quantification of GFNs in specific scenarios. Because the available quantitative techniques are somewhat limited, more research is required to distinguish GFNs from other carbonaceous materials and improve the accuracy and detection limits of GFNs at more environmentally relevant concentrations.