Approaches, Derivatives and Applications Vasilios Georgakilas,† Michal Otyepka,‡ Athanasios B. Bourlinos,‡ Vimlesh Chandra, Namdong Kim, K. Christian Kemp, Pavel Hobza,‡,§,⊥ Radek Zboril,*,‡ and Kwang S. Kim* †Institute of Materials Science, NCSR “Demokritos”, Ag. Paraskevi Attikis, 15310 Athens, Greece ‡Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University Olomouc, 17. listopadu 12, 771 46 Olomouc, Czech Republic Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, v.v.i., Flemingovo naḿ. 2, 166 10 Prague 6, Czech Republic

Functionalization of Graphene: Covalent and Non-Covalent Approaches, Derivatives and Applications

Graphene based materials: Past, present and future

Recent advances in graphene based polymer composites

Graphene has emerged as a subject of enormous scientific interest due to its exceptional electron transport, mechanical properties, and high surface area. When incorporated appropriately, these atomically thin carbon sheets can significantly improve physical properties of host polymers at extremely small loading. We first review production routes to exfoliated graphite with an emphasis on top-down strategies starting from graphite oxide, including advantages and disadvantages of each method. Then solvent- and melt-based strategies to disperse chemically or thermally reduced graphene oxide in polymers are discussed. Analytical techniques for characterizing particle dimensions, surface characteristics, and dispersion in matrix polymers are also introduced. We summarize electrical, thermal, mechanical, and gas barrier properties of the graphene/polymer nanocomposites. We conclude this review listing current challenges associated with processing and scalability of graphene composites and future perspectives f...

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Graphene/Polymer Nanocomposites

http://staff.ulsu.ru/moliver/ref/polymers/pott11.pdf

Graphene-based polymer nanocomposites

BACKGROUND: Functionalized graphene sheet (FGS) was recently introduced as a new nano-sized conductive filler, but little work has yet examined the possibility of using FGS as a nanofiller in the preparation of polymer nanocomposites. In particular, there are currently no published papers that evaluate polyurethane/FGS nanocomposites. The purpose of this study was to prepare a polyurethane/FGS nanocomposite and examine the morphological and physical properties of the material.

RESULTS: A cast nanocomposite film was prepared from a mixture of thermoplastic polyurethane (TPU) solution and FGS suspended in methyl ethyl ketone. The FGS dispersed on the nanoscale throughout the TPU matrix and effectively enhanced the conductivity. A nanocomposite containing 2 parts of FGS per 100 parts of TPU had an electrical conductivity of 10−4 S cm−1, a 107 times increase over that of pristine TPU. The dynamic mechanical properties showed that the FGS efficiently reinforced the TPU matrix, particularly in the temperature region above the soft segment melt.

CONCLUSION: Our results show that FGS has a high affinity for TPU, and it could therefore be used effectively in the preparation of TPU/FGS nanocomposites without any further chemical surface treatment. This indicates that FGS is an effective and convenient new material that could be used for the modification of polyurethane. It could also be used in place of other nano-sized conductive fillers, such as carbon nanotubes. Copyright © 2009 Society of Chemical Industry

Morphological and physical properties of a thermoplastic polyurethane reinforced with functionalized graphene sheet

A nanocomposite of waterborne polyurethane (WPU) was prepared with functionalized graphene sheets (FGSs) which are a new type of nano-sized conductive filler. The FGS were finely dispersed in a polymer matrix to improve the conductivity of the WPU. Conductivity of about 105 times that of pristine WPU was attained using two parts FGS per 100 parts of the matrix polymer. The FGS reduced the hard segment crystallinity of the WPU, which lowered the modulus of the WPU at room temperature. This modulus reduction became more evident in the temperature region above the glass transition temperature of the hard segment.

Preparation and Physical Properties of Waterborne Polyurethane/Functionalized Graphene Sheet Nanocomposites

Graphite oxide/poly(methyl methacrylate) nanocomposites prepared by a novel method utilizing macroazoinitiator

Nanocomposites of thermoplastic polyurethane (TPU), which were prepared using two types of functionalized graphene sheets (FGS) of similar thickness but different sizes were examined. The percolation threshold of the nanocomposite was reduced, evidently by increasing the particle size of the FGS. This means that the FGS with a mean particle size of 8.3 μm had a percolation threshold at 0.39 wt% in the nanocomposite of TPU, whereas it was 1.41 wt% when the FGS size was 2.4 μm. The FGS enhanced the modulus of TPU through a reinforcing effect but both the tensile strength and elongation at break were reduced as the FGS content was increased. These effects of FGS on the tensile properties were more evident with a larger particle size of FGS. The morphology and thermal properties of the nanocomposites were also examined.

Functionalized graphene sheet/polyurethane nanocomposites: Effect of particle size on physical properties

Graphite oxide (GO)/poly(methyl methacrylate) (PMMA) nanocomposites were prepared with a novel method utilizing macroazoinitiator (MAI). The MAI which has a poly(ethylene oxide) (PEO) segment was intercalated between the lamellae of GO so that it can induce the inter-gallery polymerization of methyl methacrylate (MMA) to bring the exfoliation of GO. The morphology, conductivity, thermal, mechanical and rheological properties of these nanocomposites were examined and compared with those of intercalated nanocomposites prepared by the polymerization with normal radical initiator, 2,2psila-azobisisobutyronitrile. The improvement of conductivity by GO was more evident in exfoliated nanocomposites compared to that of intercalated nanocomposites. The thermal, mechanical and rheological properties also indicated that thin GO with high aspect ratio is finely dispersed and effectively reinforced the PMMA matrix in both exfoliated and intercalated nanocomposites.

Cheol Min Shin

Papers

Morphological and physical properties of a thermoplastic polyurethane reinforced with functionalized graphene sheet

Preparation and Physical Properties of Waterborne Polyurethane/Functionalized Graphene Sheet Nanocomposites

Graphite oxide/poly(methyl methacrylate) nanocomposites prepared by a novel method utilizing macroazoinitiator

Functionalized graphene sheet/polyurethane nanocomposites: Effect of particle size on physical properties

Graphite oxide/poly (methyl methacrylate) nanocomposites prepared by a novel method utilizing macroazoinitiator