中文摘要：

本文研究了以聚乙二醇（PEG400）为分散介质的低固相体积分数（V〈10 vol%）纳米SiO2分散体系的稳态和动态的流变性能。在稳态应力实验中,当剪切速率较小时,体系具有剪切变稀现象,而剪切速率（γ.）大于临界剪切速率（γ.c）时,随剪切速率的增大,体系呈现先剪切增稠再剪切变稀的复杂变化。在动态应力实验中,体系的复合粘度随测试频率的增大而减小,并呈现剪切增稠特性。进一步研究了分散体系的pH值和固相体积分数对流变性能的影响。在酸性条件下,体系粘度较小,呈现剪切增稠现象;在中性和碱性条件下,体系粘度增大,并在高剪切应力下剪切变稀。体系的粘度随固相体积含量的增大而上升,并且由牛顿流体转变为具有剪切增稠性质的非牛顿流体。

英文摘要：

The rheological behavior of nano SiO2 dispersions in polyethylene glycol（PEG400） with low solid volume loading（V10 vol%） had been discussed under steady and oscillation stress shear.Under steady stress shear,the system shows only shear thinning when the stress is less than the critical stress（γ·γ·c）,however,the system shows shear thickening first and then shear thinning when γ·γ·c.Under oscillatory stress shear,the system shows shear thickening and the complex viscosity decreases with the increasing of frequency.The influence of pH and solid volume loading on the reological behavior was also studied.Under acidic condition,the system shows shear thickening and smaller viscosity.Under neutral and alkaline condition,the system shows shear thinning and higher viscosity.As the solid volume fraction increases,the system turns from Newtonian flow to non-Newtonian flow of shear thickening and the visocity increases.