用汉森溶解度参数评估功能化石墨烯在溶剂中的分散性
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摘要
石墨烯独特的结构使其容易团聚,不溶于大多数的溶剂,应用受到极大限制。本工作用海藻酸钠(SA)和聚乙烯吡咯烷酮(PVP)表面改性石墨烯抑制石墨烯团聚,用扫描电子显微镜、傅里叶变换红外光谱、拉曼光谱和X射线衍射仪对其进行表征,考察了两种功能化石墨烯在溶剂中的分散性,并根据分散结果计算了汉森溶解度参数。结果表明,石墨烯成功功能化,经两种分散剂表面改性的石墨烯在溶剂中的分散性改变较大,在水中分散性较好,汉森溶解度参数和汉森球半径均发生改变。汉森球半径变大表明表面改性增大了石墨烯在溶剂中的溶解度。
Graphene as a kind of twodimensional material is consisted of sp2 carbon atoms, which exhibits excellent properties, such as electronic, electrical, mechanical and thermal properties. However it is easy to form aggregation and difficult to dissolve in solvents because of its unique structure, so that the application is greatly limited. So far, most of the work reported on the dispersion of graphene without assistant of functionalization mainly in N,Ndimethylformamide(DMF) and 1-Methyl-2-pyrrolidinone(NMP), but preparation ofgraphene dispersion in other organic solvents is an vital step in application. In this work, graphene was surface modified by sodium alginate(SA) and polyvinylpyrrolidone(PVP) to restrain graphene aggregation and improve its dispersion in organic solvents. The functionalized graphene was characterized by scanning electron microscopy(SEM), Fourier transform infrared(FT-IR), Raman spectroscopy and X-ray diffraction(XRD). The dispersion of functionalized graphene in solvents was explored, and Hansen solubility parameters(HSPs) of functionalized graphene was calculated depending on their dispersion. The results showed that the functionalized graphene was successfully prepared. After surface functionalization, the dispersion of functionalized graphene in solvents was significantly changed compared with graphene and two kinds of functionalized graphene had good dispersion in water. Furthermore, HSPs and radius of HSPs sphere of functionalized graphene were changed. ?D and ?H increased and ?P decreased. These change indicated that the polar of graphene was weaken after functionalized, and its dispersion in non-polar solvents was improved. Furthermore, the increasement of radius of HSPs sphere indicated that functionalization expanded the dispersion scope of graphene in solvents.
Graphene as a kind of twodimensional material is consisted of sp2 carbon atoms, which exhibits excellent properties, such as electronic, electrical, mechanical and thermal properties. However it is easy to form aggregation and difficult to dissolve in solvents because of its unique structure, so that the application is greatly limited. So far, most of the work reported on the dispersion of graphene without assistant of functionalization mainly in N,Ndimethylformamide(DMF) and 1-Methyl-2-pyrrolidinone(NMP), but preparation ofgraphene dispersion in other organic solvents is an vital step in application. In this work, graphene was surface modified by sodium alginate(SA) and polyvinylpyrrolidone(PVP) to restrain graphene aggregation and improve its dispersion in organic solvents. The functionalized graphene was characterized by scanning electron microscopy(SEM), Fourier transform infrared(FT-IR), Raman spectroscopy and X-ray diffraction(XRD). The dispersion of functionalized graphene in solvents was explored, and Hansen solubility parameters(HSPs) of functionalized graphene was calculated depending on their dispersion. The results showed that the functionalized graphene was successfully prepared. After surface functionalization, the dispersion of functionalized graphene in solvents was significantly changed compared with graphene and two kinds of functionalized graphene had good dispersion in water. Furthermore, HSPs and radius of HSPs sphere of functionalized graphene were changed. ?D and ?H increased and ?P decreased. These change indicated that the polar of graphene was weaken after functionalized, and its dispersion in non-polar solvents was improved. Furthermore, the increasement of radius of HSPs sphere indicated that functionalization expanded the dispersion scope of graphene in solvents.
引文
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[2]Pour S Z,Ghaemy M.Polymer grafted graphene oxide:For improved dispersion in epoxy resin and enhancement of mechanical properties of nanocomposite[J].Composites Science and Technology,2016,136:145-157.
[3]Wang Z,Xue Z,Wang G,et al.Catalyst-free approach for growth of graphene sheets on high-density silica nanowires by CVD[J].Materials Letters,2016,162:165-168.
[4]Zhang J,Huang L,Zhang Y,et al.Controlled synthesis of graphene nanoribbons for field effect transistors[J].Journal of Alloys and Compounds,2015,649:933-938.
[5]Reina A,Jia X,Ho J,et al.Large area,few-layer graphene films on arbitrary substrates by chemical vapor deposition[J].Nano Letters,2009,9(1):30-35.
[6]Sarsam W S,Amiri A,Kazi S N,et al.Stability and thermophysical properties of non-covalently functionalized graphene nanoplatelets nanofluids[J].Energy Conversion and Management,2016,116:101-111.
[7]Konios D,Stylianakis M M,Stratakis E,et al.Dispersion behaviour of graphene oxide and reduced graphene oxide[J].Journal of Colloid and Interface Science,2014,430:108-112.
[8]Zhi M,Huang W,Shi Q,et al.Improving water dispersibility of noncovalent functionalized reduced graphene oxide with l-tryptophan via cleaning oxidative debris[J].Journal of Materials Science:Materials in Electronics,2016,27(7):7361-7368.
[9]Zheng F,Xu W L,Jin H D,et al.Purified dispersions of graphene in a nonpolar solvent via solvothermal reduction of graphene oxide[J].Chemical Communications,2015,51(18):3824-3831.
[10]Georgakilas V,Otyepka M,Bourlinos A B,et al.Functionalization of graphene:covalent and non-covalent approaches,derivatives and applications[J].Chemical Reviews,2012,112(11):6156-6214.
[11]Huang Q Q,Liu S L,Li K W,et al.Sodium alginate/carboxylfunctionalized graphene composite hydrogel via neodymium ions coordination[J].Journal of Materials Science and Technology,2017,33(8):821-826.
[12]Hummers W S,Offeman R E.Preparation of graphitic oxide[J].Journal of the American Chemical Society,1958,80:1339.
[13]Geng Y,Liu M Y,Li J,et al.Effects of surfactant treatment on mechanical and electrical properties of CNT/epoxy nanocomposites[J].Composites Part A:Applied Science and Manufacturing,2008,39(12):1876-1883.
[14]Gao B,Kalulu M,Oderinde O,et al.Synthesis of three-dimensional graphene architectures by using an environmentalfriendly surfactant as a reducing agent[J].International Journal of Hydrogen Energy,2017,42(29):18196-18202.
[15]Ma J,Liu J Q,Zhu W H,et al.Solubility study on the surfactants functionalized reduced graphene oxide[J].Colloids and Surfaces A,2018,538:79-85.