【摘要】 研究了Mg-Fe类水滑石(HTlc)/高岭土(kaolinite)悬浮体的质量比(R)对其流变性和触变性的影响, 发现控制剪切速率(D)得到的屈服应力(τy)和控制剪切应力(τ)得到的临界剪切应力(τc)皆随R的增大先降低后升高. 小幅振荡剪切实验发现随R 的增大, 体系由正触变性转化为复合触变性, 其中用小幅振荡剪切法在线性粘弹区发现复合触变性体系还是首次. 恒剪切速率(DL)实验发现了震荡现象, 即粘度随时间发生周期性升高和降低的变化. 震荡现象与DL 和R 有关,较高的DL 和R 可使震荡现象消失. 测定粘度随时间变化时采用的低剪切速率(DL)影响体系的触变性类型. 根据HTlc和kaolinite 粒子间的相互作用对实验结果的机理进行了探讨.更多还原

【Abstract】 The rheological properties of Mg-Fe-hydrotalcite-like compound/kaolinite suspensions, such as yield stress and thixotropy, have been investigated, mainly on the effect of mass ratio of Mg-Fe-HTlc to kaolinite suspensions (R). Both of the yield stress τy obtained in the Controlled Rate mode and critical shear stress τc obtained in the Controlled Stress mode decreased first then increased with increase of R. In the lin- ear oscillatory experiments, the type of thixotropy of HTlc/kaolinite suspensions was transformed from posi- tive thixotropy to complex thixotropy with increase of R. It was the first time to find the complex thixotropy in linear viscoelastic region by oscillatory shear measurements. In the steady shear experiments, the recovery processes have been monitored at low shear rate, finding a very interesting phenomenon, i.e., the fluctuation behavior of apparent viscosity η with t, and its disappearance when DL and R were relatively high. The re- sults were discussed on the basis of the interactions between the HTlc and kaolinite particles.更多还原