Papers by Author: Li Li Wu

Abstract: Graphene has weak interface compatibility to its solvent, and it is easy to get agglomeration in the solvent. In this paper, graphehe is modified by grafting method to improve the aqueous dispersion. Oxidized graphene is firstly prepared by modified Hummer’s method and supersonic exfoliation. Then oxidized graphene is grafted by hydrophilic polymer polyacrylamide (PAM) and deoxidized into modified graphene. The product is characterized by TEM, FTIR, Raman spectroscopy and sedimentation test. And the result demonstrates a modified graphene is successfully synthesized and its compatibility to the media is enhanced as assumption. When the ratio between PAM and graphene is 1:10, the suspension absorbance is improved as twice as common graphene’s. Meanwhile the concentration of graphene in suspension can reach 0.05mg/ml without any agglomeration.

Abstract: Graphene normally has weak interface compatibility to organics. In this paper, the surface of graphene is modified in order to improve its compatibility with polymer matrixes. Therefore, a Silane Coupling Agent(SCA) γ-Glycidoxypropyltrimethoxysilane is used to modify graphene. The results of the TEM, FTIR and sedimentation test show that SCA grafting can improve the graphene’s dispersion stability in polar organic solvent. Then modified graphene is added to epoxy resin to obtain an epoxy resin composite. The conductivity of the epoxy resin compostie can reach 8.00E-009 s/m. When additional percentage of SCA is over 0.5%, the dielectric constant (ε) has a remarkable increase.