Al-Mg类水滑石-钠质蒙脱土悬浮体的流变性

On the Rheological Behavior of Al-Mg-Hydrotalcite-like Compounds:Na-Montmorillonite Suspension

研究了带永久正电荷的Al Mg类水滑石 (Al Mg HTlc)和带永久负电荷的钠质蒙脱土 (MT)组成的悬浮体的流变性 ,主要考察了Bingham流变方程和Brinkman粘度方程的适用性 ,Al Mg HTlc/MT质量比 (R)对表观粘度 ( ηA)、Bingham屈服值 (τB)和E B系数 (K值 ) 3个流变参数的影响。实验结果表明 ,ω(MT) =1 5 %的纯MT体系和ω(MT) =1 5 % ,R =0 2的Al Mg HTlc/MT体系为牛顿体 ,ω(MT)≥ 3 %的纯MT体系和Al Mg HTlc/MT体系为假塑性体。纯MT体系符合Bingham流变方程 ;Al Mg HTlc/MT体系在低剪切速率 (D ,0～ 3 0 0s-1)区不符合Bingham流变方程 ;纯MT体系和Al Mg HTlc/MT体系在研究的范围内均符合Brinkman粘度方程。ηA、τB 和K值随R的增大均呈现为先增大后降低的变化 ,在R =0 2 5时出现最大值。对颗粒间的相互作用机理和表征参数进行了探讨 ,认为Brinkman粘度方程的E B系数K值是能表征体系粒子间内在相互作用的“本征流变参数”。

The rheological behavior of the suspension consisted of alumimum-magnesium hydrotalcite-like compounds(Al-Mg-HTlc) with permanent positive charge and Na-montmorillonite(Na-MT) with permanent negative charge have been studied as function of the applicability of the Bingham rheological equation and the Brinkman viscosity equation. The influences of Al-Mg-HTlc/MT mass ratio(R) on apparent viscosity(η_A), Bingham yield stress(τ_B) and E-B coefficient(K) were also investigated. The results show that the suspension with ω(MT)=1.5% and the Al-Mg-HTlc/MT suspension with the same MT, contnet and R=0.2 belong to Newtonian fluid; the pure MT suspension with ω(MT)≥3% and the Al-Mg-HTlc/MT suspension with ω(MT)≥3% belong to pseudoplastic fluid. The pure MT suspension conforms to the Bingham rheological equation , whereas the Al-Mg-HTlc/MT suspension conforms to the Bingham equation only at high shear rate ( D= 300～1 100 s -1 ). Both the pure MT suspension and Al-Mg-HTlc/MT suspensions conform to the Brinkman viscosity equation in the range of 0～1 022 s -1 shear rate. All the η_A, τ_B and K values were found increased with increase in R and went through a maximum at R around 0.25. The mechanism of interaction between the particles and the characteristic parameters were discussed. It is concluded that the E-B coefficient K of the Brinkman viscosity equation is the ‘Intrinsic Rheological Parameter’ , characteristic of the internal interaction among the particles of the system.