As reported earlier,

this induction period may account for the initial delay in reaching equilibrium between propagating radicals and dormant species. This delay may be responsible for the irreversible termination of some of the primary radicals in MMA polymerization, resulting in the deviations that are observed in the time vs. ln([M]0/[M]) plot. Further CRP was confirmed by plotting conversion against the number of average molecular weight ( ), as shown in Figure 6. A linear increase in molecular weight was observed with increasing monomer conversion, which confirms that the polymerization of MMA on the DGO-Br proceeds through the CRP mechanism. The deviation of the conversion vs. plot is also correlated with slow initiation. These plots show that MMA polymerization undergoes

an induction period with slow initiation, as reported previously [25]. Table 1 Polymerization of MMA using TPEBMP selleck kinase inhibitor at 80°C in DMF using DGO-Br Code Time (h) aConversion (%) GPC results GP-1 2 23 3.8173 1.8621 2.05 GP-2 3 30 4.4302 2.3565 1.88 GP-3 4 44 5.3074 3.2561 1.63 GP-4 5 55 5.7492 APO866 supplier 4.2274 1.36 GP-5 6 64 6.2888 4.9132 1.28 aConversion was determined gravimetrically. Figure 4 GPC curves of PMMA recovered from graphene-PMMA nanocomposites by reverse cation www.selleckchem.com/products/DAPT-GSI-IX.html exchange. Figure 5 Time vs. conversion and time vs. ln[M] 0 /[M] plots for the polymerization of MMA using DGO-Br. Figure 6 Conversion vs. and conversion vs. polydispersity index (PDI; ) plots for the polymerization of MMA using DGO-Br. Conclusions ATRP initiator-attached high-density functionalized graphene oxide (DGO-Br) was prepared

and used for MMA polymerization, resulting in graphene-PMMA nanocomposites through controlled radical polymerization. DSC and TGA studies show that the graphene-PMMA nanocomposites exhibited higher T g and higher thermal stability compared to pristine PMMA polymers. GPC results confirmed the presence of a controlled radical polymerization mechanism using functionalized DGO-Br. We believe that high-density functionalized GO can be used to develop graphene-polymer nanocomposites with enhanced properties. Acknowledgements This research was supported by the Basic Science Research Pro-gram through BCKDHA the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2013R1A1A2A10004468). References 1. Novoselov KS, Geim AK, Morozov SV, Jiang D, Zhang Y, Dubonos SV, Grigorieva IV, Firsov A: Electric field effect in atomically thin carbon films. Science 2004, 306:666–669. 10.1126/science.1102896CrossRef 2. Morozov SV, Novoselov KS, Katsnelson MI, Schedin F, Elias DC, Jaszczak JA, Geim AK: Giant intrinsic carrier mobilities in graphene and its bilayer. Phys Rev Lett 2008, 100:016602.CrossRef 3. Balandin AA, Ghosh S, Bao W, Calizo I, Teweldebrhan D, Miao F, Lau CN: Superior thermal conductivity of single-layer graphene. Nano Lett 2008, 8:902–907. 10.1021/nl0731872CrossRef 4.