硅烷功能化石墨烯/硅树脂纳米复合材料的制备与表征

先用乙烯基三甲氧基硅烷(A-171)和二甲肼改性并还原氧化石墨烯(GO),制备A-171功能化的石墨烯(FG).研究结果表明A-171与GO上的羟基发生了反应,以共价键连接到了石墨烯的表面;FG能在四氢呋喃中均匀分散并且剥离成厚度约为0.9 nm的单一片层,其干燥后表面呈褶皱状.然后将FG与双组分硅树脂用溶液共混法制备了FG/硅树脂纳米复合材料.运用X射线衍射、扫描电子显微镜、动态热机械分析、拉伸试验等手段分析了复合材料的形态与性能,结果表明,与未处理过的石墨烯相比,FG在复合材料中有更好的分散和更强的界面作用.含0.5 wt%FG的复合材料的拉伸强度较硅树脂提高了87.7%,玻璃化温度提高了23.9℃,失重5%时的温度也提高了20.1℃.

PREPARATION AND CHARACTERIZATION OF SILANE FUNCTIONALIZED GRAPHENE/SILICONE NANOCOMPOSITES

Functionalized graphene(FG) was firstly synthesized by reacting graphene oxide(GO) nanosheets with vinyl trimethoxy silane(A-171) and simultaneously reducing by dimethylhydrazine in dimethylformamide(DMF) solvent.Investigation results confirmed that the A-171 molecules were attached on the surface of FG sheets by Si—O—C,meanwhile most of residual oxygen-containing functional groups of GO were reduced and the sp2-hybridized structure of graphene was restored.The introduction of A-171 molecules led to an excellent dispersibility and completely exfoliation of FG with a thickness of about 0.9 nm in the tetrahydrofuran(THF) solvent.Subsequently,FG/silicone composites were prepared via solution blending method.Finally,X-ray diffraction,scanning electron microcopy,dynamic mechanical analysis,thermogravmetric analysis and tensile test were performed to measure the morphology and properties of the FG/silicone composites.Results showed that compared with untreated graphene,FG had a better dispersion in the composites,as well as a stronger interfacial adhesion with silicone matrix.The tensile strength of the composites increased with increasing FG content.When the content of FG reached 0.5 wt%,the composite showed a tensile strength of 4.73 MPa,which is 87.7% higher than that of neat silicone.The 5% weight loss temperature and the glass transition temperature of the composite exhibited a 20.1 K and 23.9 K increase by addition of 0.5 wt% FG.