Feb 24, 2009
Functionalized graphene sheet makes polymeric coatings more protective
Very recently, graphene has been reported to be the strongest material in the world. Using functionalized graphene sheets to reinforce polymers has generated a great deal of interest. The functional groups attached to the graphene sheets could de-aggregate the nano-sized sheets in organic solvents and polymer matrices. A report (J. Mater. Chem. 17(2007), 3678) disclosed a simple method to fabricate fully exfoliated FGSs in an organic solvents. With this method in hand, the barrier for well-dispersion of the graphene sheets in polymeric matrix can be easily swept out.
Polyurethane (PU) is one of most versatile polymeric materials and has a wide application as surface coatings. In this work, published in Nanotechnology , it was found that the formation of chemical bonding between functionalized graphene sheets and PU macromolecules allowed a significant stress transfer. With the incorporation of 4.4 wt% graphite oxide nanoplatelets, the Young's modulus and hardness of the PU was significantly increased by ~900% and ~327%, respectively. Nanoindentation tests revealed that the scratch resistance was exceptionally improved as shown in the figure. It points to the promising application of composite materials in surface coating. It was expected that the 2D structure of the graphene sheets could improve the barrier properties of coatings like nanoclay. Also, if it is proven in future work, the surface coatings will not only be reinforced, but also functionalized by the graphene sheets.
About the author
This work was carried out at the Department of Materials, Loughborough University. Dongyu Cai is a third-year PhD student under supervision of Dr Mo Song. His research is focusing on the development of high performance polymer nanocomposites. Kamal Yosuh is another third-year PhD student in Dr Mo Song’s research group. He is currently investigating the surface properties of polyurethane nanocomposite coatings. Dr Mo Song is a reader in polymer science and has broad research interests in the multidisciplinary fields of polymer nanocomposites, conductive polymer composites for anti-static and thermal management, mesoporous materials for environment protection, physics and chemistry of carbon nanotube and graphite, chitosan-based biopolymers, functional polymeric and high temperature coatings and modern thermal analysis of polymers.