中文摘要：

为提高氧化石墨烯（GO）的生物相容性从而扩展其在高性能生物材料制备中的应用,采用甲苯-2,4-二异氰酸酯作为桥联剂,制备了四臂星型聚乙二醇修饰氧化石墨烯（GO-TDI-sPEG）,该产物在水中仍然可以稳定分散.采用傅里叶红外光谱（FTIR）、拉曼光谱（Raman）、X-射线衍射（XRD）、原子力显微镜（AFM）、透射电子显微镜（TEM）和热重分析（TGA）对接枝产物进行表征.产物在2861 cm-1和1093 cm-1处出现的特征红外吸收表明sPEG已接枝到GO上.产物的Raman光谱中D模与G模信号变弱,且ID/IG值变化不大,说明sPEG改性后的氧化石墨物理结构没有发生变化.XRD曲线上产物衍射峰消失,表明经聚合物修饰后氧化石墨被完全剥离.TGA数据表明原始GO在约160℃开始发生热失重,经修饰后,大约在260℃开始热失重,热稳定性增加了约100℃.由TEM图片可以观察到GO及改性石墨烯产物剥离程度较高,且片上分布有较多聚合物点.且AFM图片显示GO的平均厚度大约为0.85 nm,接上聚合物后部分厚度增加到约1.2 nm.

英文摘要：

In order to improve the biocompatibility of graphene oxide （GO） and enhance its application in preparing biomaterials,four-arm star polyethylene glycol （sPEG） was used to modify GO under the assistance of toluene-2,4-diisocyanate （TDI）. Polyethylene glycol-modified graphene oxide （GO-TDI-sPEG） obtained by this facile method possesses high sPEG grafting density,which could be stably suspended in aqueous solutions. Fourier transform infrared spectroscopy （FTIR） , Raman spectroscopy （Raman） , X-ray diffraction （XRD） , atomic force microscopy （AFM）, transmission electron microscopy （TEM） and thermogravimetric analysis （TGA） were used to characterize the resultant material. The appearance of the characteristic absorptions at 2861 and 1093 cm-1 in FTIR spectrum,as well as the AFM and TEM micrographs indicated that sPEG was successfully grafted onto GO. No diffraction peak could be found in XRD figure of GO-TDI-sPEG, which indicated that the layers of GO-TDI-sPEG were fully exfoliated after modification. The TGA test results showed that the thermal stability of the modified GO had been greatly increased and the grafting degree of sPEG in GO- TDI-sPEG was about 12. 1 wt%.