石墨烯/聚氨酯纳米复合材料的制备及力学性能研究

采用改进的Hummers法制备出氧化石墨烯(GO),并用苯基异氰酸酯对其功能化,接着将功能化的氧化石墨烯(iGO)与4,4’-二苯甲烷二异氰酸酯(MDI)在二甲基甲酰胺(DMF)溶剂中进行超声混合得到均匀混合液,再将混合液与聚四亚甲基醚二醇(PTMG)、1,4-丁二醇(BD)在DMF溶剂中进行原位聚合制备iGO/热塑性聚氨酯(TPU)纳米复合材料(GO-TPU),同时在相同条件下合成PU以供对比.采用XRD、FT-IR、XPS、Raman光谱、SEM和万能拉伸试验机对GO的功能化效果及GO-TPU的性能进行了表征.结果表明:苯基异氰酸酯成功接枝于GO表面,iGO在TPU基体中分散均匀,复合材料的拉伸强度和断裂伸长率均随GO含量的增加表现为先增大后减小的变化规律,当iGO的质量分数为1％时GO-TPU的拉伸强度和断裂伸长率均为最大值,分别为4.26 MPa和500％,与纯TPU相比,分别提高了127.1％和27.3％.
Graphene oxide (GO) was prepared via improved Hummers method, and then the GO was functionalized with phenyl isocyanate. Subsequently, functionalized GO (iGO) and 4，4′-diphenylmethane diisocyanate (MDI) were mixed under sonication in dimethylformamide (DMF) solvent to obtain a homogeneous mixture. The mixtures were reacted with polyoxytertramethylene glycol (PTMG) and 1,4-butanediol (BD) in DMF solvent to prepare the iGO/thermoplastic polyurethane (PU) nanocomposites (called GO-TPU), while neat TPU was synthesized under the same conditions for comparison. Characterizations were carried out by XRD, FT-IR, XPS, Raman spectroscopy, SEM and mechanical properties were tested. The results show that the phenyl isocyanate is successfully grafted onto the surface of GO. The tensile strength and elongation at break of nanocomposites are increased first and then decreased with the increase of iGO. Uniform dispersion of iGO is observed in the PU matrix when the content is less than 1 %(mass fraction). It is found that the most significant improvement of the tensile strength (4.26MP) and elongation at break (500 %) is obtained with iGO at 1% content. When compared with neat TPU, the increase is 127.1% and 27.3%, respectively.