The increase of T g at low loading can be attributed to the restricted movement of the PS chains. In the case of FGO-HDA/PS,
this tendency was not clear. As described in the above section, the tangled and agglomerated conformation of FGOs with longer alkyl chains of HDA had little effect on the chain movement of the PS chains Niraparib but acted as a spacer between the PS chains [11, 26]. However, as the loading of the FGOs increased, all the T g values of FGO/PS decreased. This can be attributed to the increased spaces between the PS chains at the higher FGO loadings, regardless of the chain length of the alkylamines. Table 1 Glass transition temperatures obtained from the tan δ curves FGO loading (wt.%) FGO-OA/PS (°C) FGO-DDA/PS this website (°C) FGO-HDA/PS (°C) 0.0 110.44 110.44 110.44 1.0 111.95 111.44 111.44 3.0 112.45 112.43 110.36 5.0 111.19 110.44 110.94
10.0 108.67 109.17 108.42 check details Conclusions Three types of FGO/PS composites were successfully prepared by solution blending. FGOs in the form of grafted alkylamines showed excellent dispersion over PS even at 10 wt.% loading. The dispersed FGOs formed different morphologies over the PS matrix due to the steric effects resulting from the different chain lengths of the alkylamines. All of the FGO/PS composites possessed improved thermal properties and storage moduli with FGO loading. FGO-HDA/PS, which has the longest chain length, showed the best thermal stability compared to other alkylamines. On the other hand, the storage modulus of the FGO-OA/PS composite achieved a maximum value of 3,640 MPa at 10 wt.% FGO-OA loading,
which corresponded to 140% of the pristine PS. The functionalization of GO with alkylamines is thought to improve the compatibility of GO with various low-polar polymers due to their good interfacial interaction. Acknowledgements This research was supported by the Basic Science Research Program through the National Research Nutlin-3 Foundation of Korea (NRF) funded by the Ministry of Education (2011–0022485). References 1. Geim AK, Novoselov KS: The rise of graphene. Nat Mater 2007, 6:183–191.CrossRef 2. Allen MJ, Tung VC, Kaner RB: Honeycomb carbon: a review of graphene. Chem Rev 2010, 110:132–145.CrossRef 3. Stankovich S, Dikin DA, Dommett GHB, Kohlhaas KM, Zimney EJ, Stach EA, Piner RD, Nguyen ST, Ruoff RS: Graphene-based composite materials. Nature 2006, 442:282–286.CrossRef 4. Pham VH, Cuong TV, Dang TT, Hur SH, Kong B-S, Kim EJ, Shin EW, Chung JS: Superior conductive polystyrene-chemically converted graphene nanocomposite. J Mater Chem 2011, 21:11312–11316.CrossRef 5. Ramanathan T, Abdala AA, Stankovich S, Dikin DA, Herrera-Alonso M, Piner RD, Adamson DH, Schniepp HC, Chen X, Ruoff RS, Nguyen ST, Aksay IA, Prud’Homme RK, Brinson LC: Functionalized graphene sheets for polymer nanocomposites. Nat Nanotechnol 2008, 3:327–331.CrossRef 6.