本文用流变学的方法在Brabender流变仪上研究了不同因素对二氧化钛悬浮体流变性的影响．在同一体积分率下，与粒度分布宽的颗粒形成的悬浮体相比，粒度分布窄的颗粒形成的悬浮体其屈服应力和稳态剪切粘度较大；在二氧化钛体积分率很小时，悬浮体呈牛顿性；当体积分率大于一定值时，悬浮体具有零剪切粘度和剪切稀化特征；当其大于一临界值时，存在屈服应力并有强烈的剪切稀化行为．悬浮体粘度服从广义Quemada流变方程．在温度＜40℃时，温度升高使粘度和屈服应力降低；在温度＞40℃时，温度升高，屈服应力升高，而粘度在不同的剪切速率范围内有复杂的行为，这可用分散介质中颗粒的碰撞理论来解释．
The rheological properties of TiO2/water suspensions were examined by means of Brabender rheometer
with rheological method. It was observed that yield stress and steady shear viscosity of TiO2/water suspensions with narrow PSD is higher than those
of TiO2/water suspensions with wide PSD. When volume fraction of particle Φ is very low, the suspension exhibits Newtonian behavior. All tested pastes
exhibit shear-thinning behavior when volume fraction of particle Φ is higher than a certain value; when Φ beyond a critical value, the pastes have yield
stress and exhibit more obvious shear-thinning behavior. The shear viscosity of TiO2/water suspensions follows a generalized Quemada model and parameters
were obtained by simulating. When the temperature is below 40℃, the shear viscosity and yield stress decrease with the increasing of temperature;
when the temperature is higher than 40℃, yield stress increases with the increasing of temperature while shear viscosity exhibits complex
behavior. The temperature dependence of shear viscosity and yield stress can be explained by collision theory of fine particles in suspending mediums.
参考文献
| [1] | Jones A R, Leary B, Boger D V. J. Colloid Int Sci., 1992, 150: 84--96. [2] Rechmann H. VII FATIPEC Congress, 1964. [3] 古宏晨, 金树柏, 蔡世银等. 力学与实践, 1996, 18 (5): 48--51. [4] 张辉, 方图南, 戴干策. 化工学报, 1996, 47 (3): 351--356. [5] Quemada D, Fland P, Jezequel P H. Chem. Eng. Comm, 1985, 32: 61--83. [6] Barnes H A, Hutton J F, Walters K. An introduction to rheology. London:Elsevier publication. 1989. [7] Hoffman R L. Trans Soc. Rheol, 1979, 16: 155--159. [8] Tiu C, Podolsak A K, Fang T N, et al. Rheo Acta, 1992, 31: 381--389. |
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