剪切增稠液流变性能的影响因素研究

Influence factor of rheological property on STF

分别以直径85nm、700nm的纳米SiO2粒子作为分散相,PEG200、PEG400、PEG600作为分散介质,通过超声波震荡和机械搅拌的方式制备不同黏度的剪切增稠液(STF)。采用JEM-2100HR型透射电镜观察纳米SiO2粒子的外观形貌,利用Nano-ZS90型粒径分析仪测试纳米SiO2粒子的直径及分布,采用MCR302型流变仪测试STF的稳态流变性能。结果表明,直径85nm的纳米SiO2粒子易团聚,直径700nm的纳米SiO2粒子不易团聚。在一定剪切速率范围内,STF体系的黏度随着剪切速率的增加呈现出"先变稀再增稠"的现象。STF体系的初始黏度、突变黏度、最大黏度均随着纳米SiO2粒子质量分数或PEG分子量的增加而增加;STF体系的突变剪切速率则随着纳米SiO2粒子质量分数或PEG分子量的增加而下降。

Nano silica particles(nano-SiO2 particles) with diameter of 85 nm and 700 nm used as the dispersed phase and PEG 200,PEG400 and PEG600 used as the dispersion medium,respectively. Different system Shear thickening fluid(STF) were prepared by method of mechanical stirring and ultrasonic shock. The morphology and agglomeration of nano-SiO2 particles were observed by JEM-2100 HR transmission electron microscope. Particle diameter and distribution of nano-SiO2 particles were tested by Nano-ZS90 grain size analyzer. And steady rheological properties of STF were tested by MCR302 rheometer. The results shown that the agglomeration of nano-SiO2 particles with diameter of 85 nm was obvious,and net structures were observed too,while that of 700 nm was not obvious. In certain range of shear rate,viscosity of STF appeared the phenomenon of first thinning then thickening with the increase of shear rate. Initial viscosity,mutation viscosity and biggest viscosity of STF all increased,while mutation shear rate decreased with the increase of nano-SiO2 particles’ concentration or PEG’s molecular weight.