By a News Reporter-Staff News Editor at Science Letter -- Current study results on Styrenes have been published. According to news originating from Freiburg, Germany, by NewsRx correspondents, research stated, "Herein we report on the solvent-free free radical grafting of styrene homo- and copolymers onto functionalized graphene nanosheets without requiring initiator addition. The key intermediate is an organophilic stearylamine-modified graphite oxide (Stearyl-GO), containing both olefinic unsaturation and stable graphene radicals."
Our news journalists obtained a quote from the research from the University of Freiburg, "According to the online tracking of the C-centered graphene radicals by time-resolved EPR spectroscopy, the graphene radical concentration markedly increases during the early stage of polymerization and is depleted as the viscosity builds up with progressing styrene conversion. 'Grafting-to' by addition of polystyrene radicals to graphene and 'grafting-from' by graphene-initiated free radical polymerization afford high graft yields, as determined by ultracentrifugal separation of polystyrene-grafted functionalized graphene (PS-g-FG) from the styrene homopolymer byproduct. The addition of TEMPO enables control of the further grafting yields by a controlled radical 'grafting-from' polymerization. In sharp contrast to graphene/polystyrene solution blends (PS/Stearyl-GO), morphological and rheological investigations reveal that the in situ formation of PS-g-FG accounts for much more uniform graphene dispersion in polystyrene melts and also in various organic solvents. This is paralleled by enhanced elasticity of the graphene particle network and markedly improved electrical conductivity of the resulting graphene/polystyrene nanocomposites."
According to the news editors, the research concluded: "Owing to the effective polymer radical addition to FG, both Stearyl-GO and PS-g-FG significantly improve the thermal stability of polystyrene, as measured by thermogravimetric analysis of thermal decomposition during prolonged heating at 250 degrees C. This versatile in situ self-initiated polymerization process enables grafting of styrene copolymers with butyl acrylate and acrylonitrile."
For more information on this research see: Self-Initiated Free Radical Grafting of Styrene Homo- and Copolymers onto Functionalized Graphene. Macromolecules, 2013;46(14):5488-5496. Macromolecules can be contacted at: Amer Chemical Soc, 1155 16TH St, NW, Washington, DC 20036, USA. (American Chemical Society - www.acs.org; Macromolecules - www.pubs.acs.org/journal/mamobx)
The news correspondents report that additional information may be obtained from F. Beckert, University of Freiburg, Inst Phys Chem, D-79104 Freiburg, Germany. Additional authors for this research include A.M. Rostas, R. Thomann, S. Weber, E. Schleicher, C. Friedrich and R. Mulhaupt (see also Styrenes).
Keywords for this news article include: Europe, Germany, Freiburg, Polystyrenes, Free Radicals, Benzene Derivatives, Inorganic Chemicals, Benzylidene Compounds
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