硅烷功能化石墨烯/硅树脂纳米复合材料的制备与表征

PREPARATION AND CHARACTERIZATION OF SILANE FUNCTIONALIZED GRAPHENE/SILICONE NANOCOMPOSITES

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℃.

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 O. 9 nm in the tetrahydrofuran （THF） solvent. Subsequently, FG/silicone composites were prepared via solution blending method. Finally, X-ray diffraction,scanning electron microeopy, dynamic mechanical analysis, thermogravmetric analysis and tensile test were performed to measure the morphology and properties of the FG/silieone composites. Results showed that compared with untreated graphene, FG had a better dispersion in the composites, as well as a stronger interracial 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.