氧化石墨烯分散体系的流变性能

Rheological properties of graphene oxide dispersion system

利用扫描电子显微镜对氧化石墨烯(GO)微观结构进行表征,从黏度、表面张力等角度分析GO分散体系的流变性能,研究GO在多种胺类有机溶剂及水基中的分散行为及其湿法纺丝性能。结果表明,在相同用量下,小尺寸GO分散体系的黏度小于大尺寸GO分散体系;在相同体系浓度下施加不同剪切应力,分散体系出现剪切变稀现象,即剪切速率越高,黏度越低;添加乙二胺的GO分散体系黏度较添加二乙醇胺、二正丁胺大,添加量为0.2%时黏度达到6 150 mPa·s;GO/乙二胺分散体系的表面张力(76.1mN/m)也比其他2种含胺类有机溶剂体系大;大尺寸石墨烯(rGO)纤维的断裂强度较高,达到14.5 MPa;而小尺寸rGO纤维的拉伸伸长率较大,达到34%。

The microstructure of graphene oxide(GO) was characterized by scanning electron microscopy. The rheological properties of GO dispersion system were analyzed from the perspectives of viscosity and surface tension. The dispersion behavior of GO in various amine organic solvents and water base and its wet spinning properties were studied. The results showed that at the same dosage, the viscosity of small size GO dispersion system was smaller than that of large size. When different shear stresses were applied at the same system concentration, the dispersed system showed shear thinning phenomenon. The higher the shear rate, the lower the viscosity. The viscosity of the GO dispersion system with ethylenediamine was higher than that of system with diethanolamine and din-butylamine, and the viscosity reached 6 150 mPa·s with addition amount of 0.2%. The surface tension of the GO/ethylenediamine dispersion system(76.1 mN/m) was higher than that of the other two systems containing amine organic solvents. The breaking strength of large size graphene(rGO) fiber was higher, which was 14.5 MPa, while the tensile elongation of small size rGO fiber was bigger, which could reach 34 %.