不同体系剪切增稠液体的流变行为研究

剪切增稠液体是指其表观粘度随剪切速率增加而变大的一类流体。工业生产中，剪切增稠的出现会阻碍输送管道，破坏生产设备。针对这种情况，人们对如何降低流体粘度造成的不利影响进行了大量研究。另一方面，剪切增稠液体是“液体防弹材料”的关键组成部分，并且在减震、控制方面也具有可观的应用潜力。该文采用原生粒径为50 nm 的SiO2和80～100 nm 的 CaCO3分别作为分散相，聚乙二醇（PEG）200为分散介质，采用超声分散法制备得到不同固含量的剪切增稠液。并通过纳米粒度仪和扫描电镜对分散相粒子团聚情况进行分析；通过应力控制流变仪分别对 SiO2/PEG200和 CaCO3/PEG200悬浮分散体系的稳态流变性能进行分析。结果表明，两种体系试样在测试中均出现剪切增稠现象，并且分散相质量分数越高，剪切增稠效果越明显；而高质量分数的 SiO2/PEG200体系的粘度变化范围更大，增稠现象更为明显。

Rheological behavior of different shear thickening fluids

Shear thickening fluid （STF）is a system whose apparent viscosity increases with rising shear rate. In recent ten years,studies on STF mainly discuss about its rheological properties and applications as the main com-ponent of ＆quot;liquid body armor＆quot;.In this article,SiO2 powder with the diameter of 50 nm and CaCO3 with the diameter of 80 ~100 nm were used as the dispersed particles,respectively.Further homogeneously dispersing nano particles into polyethylene glycol 200 （PEG200）with ultrasonic method,a uniformly dispersed suspension system was a-chieved.Here Stress control rheometer was applied to characterize the rheological properties of suspensions under steady shear rate.The results showed that in both two systems,the thickening behavior became more obvious with in-creasing dispersed phase content.Compared with CaCO3 /PEG200 system,SiO2 /PEG200 sample with high SiO2 con-tent has wider viscosity range,and the phenomenon of shear thickening is more apparent.