胶含量、pH值及电解质对Mg-Fe-HTlc/高岭土分散体系流变性的影响

胶含量、pH值及电解质对Mg-Fe-HTlc/高岭土分散体系流变性的影响;类水滑石化合物;高岭土;剪切应力;分散体系;流变性     

Mg-Fe-HTIc／高岭土悬浮体流变性研究

研究了Mg—Fe类水滑石(HTIc)／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拘增大先降低后升高．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和尺可使震荡现象消失．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HTIc和kaolinite粒子间的相互作用对实验结果的机理进行了探讨．     

Mg-Al类水滑石/高岭土分散体系流变振荡现象研究

恒剪切速率(DL)实验发现Mg-Al类水滑石(HTlc)/高岭土(kaolinite)分散体系中存在流变震荡现象,即粘度随时间发生周期性升高和降低的变化.研究了HTlc/kaolinite分散体系的质量比(R)、剪切速率、pH、无机盐及聚合物等因素对振荡现象的影响,发现较高的DL与无机盐含量均可使震荡现象消失.pH值及...     

Mg-Fe-HTlc对黄原胶流变性的影响

研究了荷负电高分子物质黄原胶(XG)及类水滑石HTlc/XG复合悬浮体系的流体类型及触变性. 结果发现, 供试体系流变曲线都符合Herschel-Bulkley模型. 在0.05～0.20 wt%范围内, 随XG含量增加, XG溶液表现出由假塑性流体到塑性流体的转变, 没有触变性|1.5 wt%纯HTlc悬浮体系为牛顿流体, 无触变性. 当HTlc/XG质量比为29.0～6.5时(复合悬浮体系固含量保持为1.5%), 体系均表现为假塑性流体|除HTlc/XG质量比为29.0体系无触变性外, 其它复合悬浮体系均表现为正触变性.     

Al-Mg类水滑石-钠质蒙脱土悬浮体的流变性

Al-Mg类水滑石-钠质蒙脱土悬浮体的流变性     

镁铝类水滑石/阳离子淀粉分散体系流变学振荡行为研究

采用稳态剪切和小振幅振荡剪切实验研究了镁铝类水滑石化合物(Mg-Al HTlc)/阳离子淀粉(CS)分散体系(HTlc与CS质量之比R分别为0, 0.02, 0.05和0.08)的流变学性质．实验结果表明: 上述体系在实验pH值(5～11)范围内均为剪切稀释非牛顿流体, 其中, Mg-Al HTlc/CS (R＝0, 0.02和0.05)分散体系的流变曲线符合幂律模型, 而Mg-Al HTlc/CS (R＝0.08)体系符合Herschel-Bulkley模型. 上述体系先于1000 s^－1剪切180 s, 再于1 s^－1(或者3 s^－1)低速剪切时均表观出粘度随时间周期变化的振荡现象. 振荡现象缘于CS分子结构的周期变化. pH值、剪切速率和HTlc含量的变化可以改变振荡周期(频率)和振幅. 低pH值条件下, Mg-Al HTlc/CS (R＝0.08)体系先于1000 s^－1剪切180 s, 再于小振幅振荡剪切(剪切应力0.03 Pa, 频率0.5 Hz)时储能模量G?和损耗模量G?也表现出随时间周期变化的振荡现象.     

无机电解质及聚合物对Mg-Al混合金属氢氧化物—高岭土分散体系触变性的影响

类水滑石;流变学;无机电解质及聚合物对Mg-Al混合金属氢氧化物—高岭土分散体系触变性的影响     

pH值对Fe-Al-Mg-MMH/钠质蒙脱土悬浮体触变性的影响

研究了pH值对Fe-Al-Mg型混合金属氢氧化物／钠质蒙脱土（简称MMH／MT）悬浮体触变性的影响。发现pH值能影响其触变性类型：m(MMH)/m(MT)(下文中以R表示）较低时（0，0．013和0．051），随着pH增高，体系有由负触变性－复合触变性－正触谱性转变的趋势；而R较高的体系（R＝0．091），随pH的增高，体系由复合触变性向负触变性转化。探讨了各种触变性产生的原因和pH的影响机理。     

Mg-Al-MMH-高岭土分散体系触变性研究

触变性是分散体系流变学研究的重要内容之一,在外切力作用下,若体系的粘度随时间下降,静止后又恢复,即具有时间因素的切稀现象,称为正触变性（positive thixotropy);反之,若体系的粘度或切力上升,静止后又恢复,即具有时间因素的切稠现象,称之为负触变性（Negative thixotropy)^[1],若在外切力作用下,某个特定体系的粘度或切力随时间先后呈现出正触变性和负触变性特征,则称之为复合触变性（Complex thixotropy)^[2,3],目前,对各种触变性机理的认识尚不统一。     

阳离子淀粉/Mg-Al类水滑石悬浮体系的粘度行为

阳离子淀粉;Mg-Al类水滑石;流变性;粘度     

Influence of Montmorillonite's Concentration on the Thixotropy of Hydrotalcite-like Compounds/Montmorillonite Suspensions

In this paper, we found that the change of sodium montmorillonite's (MT) concentration in the magnesium‐aluminum‐ferrum hydrotalcite‐like compounds (Mg‐Al‐Fe‐HTlc)/MT suspensions would greatly influence the thixotropic type of the suspensions. Specifically, the increase in the MT's concentration increases the viscosities (η) of the HTlc/MT suspensions with the same R value (the mass ratio of HTlc to MT was signed as R, e.g., R=m_HTlc/m_MT), meaning that the structure strength of the HTlc/MT suspensions increases. With the variation of MT's concentration, the thixotropic type of the HTlc/MT suspensions changed accordingly, and the mechanism has been discussed in this paper.     

Thixotropic Behavior of Hydrotalcite-Like Compound/Cationic Starch Suspensions: Effects of Mass Ratio of Hydrotalcite-Like Compound to Cationic Starch,Electrolyte, and Temperature

The thixotropic behavior of Mg-Al hydrotalcite-like compound (HTlc)/cationic starch (CS) suspensions was investigated as a function of the mass ratio (> 0.08) of HTlc to CS, the electrolyte and the temperature, respectively. The thixotropy was studied by monitoring viscosity (η) change during the recovery process as a function of time (t) after the cessation of intensive shear. The results showed that the strength of negative thixotropy of the CS solution decreased with the increasing of electrolyte (NaCl, CaCl₂, or AlCl₃) concentration and the temperature. The thixotropic type of the HTlc/CS suspensions could transform from negative to complex, positive, complex, and then to negative thixotropy with the increasing of HTlc content if CS was the main component of the suspensions. In addition, the thixotropic type of the HTlc/CS suspensions transformed from original type to positive thixotropy with the increasing of electrolyte concentration and the temperature.     

Effect of Electrolytes and Polymers on the Thixotropy of Mg‐Al‐Layered Double Hydroxides/Kaolinite Dispersions

The effect of electrolytes (NaCl and CaCl₂) and polymers (CPAM and HPAM) on the thixotropy of Mg‐Al‐layered double hydroxide (LDHs)/kaolinite dispersions has been investigated. It was observed that the type of thixotropy in LDH/kaolinite dispersions may be affected by NaCl, but not by CaCl₂ in range of concentration of interest. The type of thixotropy in LDH/kaolinite dispersion with R=0 transformed from positive thixotropy to complex thixotropy and at last positive thixotropy again with the concentration of NaCl in range of 0.00–0.10 mol·L⁻¹; the type of thixotropy in LDHs/kaolinite dispersions with R=0.25 transformed from complex thixotropy to positive thixotropy and then complex thixotropy again with the concentration of NaCl in range of 0.00–0.10 mol·L⁻¹. The type of thixotropy in LDH/kaolinite dispersion with R=0 may be not affected by cationic polyacrylamide (CPAM) and hydrolyzed polyacrylamide (HPAM); but the LDHs/kaolinite dispersions with R=0.25 transformed from complex thixotropy to positive thixotropy with the both polymers concentration in range of interest, which indicated that the microstructure of the dispersion changed from weak folc sediments structure to steric network structure.     

Influence of pH on the thixotropy of magnesium aluminum hydroxide-kaolinite suspension

The influence of pH on the thixotropy of pure kaolinite suspension and magnesium aluminum hydroxide (Mg-AI-MMH)-kaolinite suspension was studied. The results show that the thixotropic type of pure kaolinite suspension was not affected by pH studied in the range of 3.60-12.00. The thixotropic type of Mg-AI-MMH-kaolinite suspension with mass ratio (R) value of MMH to kaolinite 0.029 transformed from complex thixotropy into positive thixotropy with increasing of pH in the range of pH 3.83-12.00, and the type of thixotropy of Mg-AI-MMH-kaolinite suspension with R = 0.129 transformed from positive thixotropy into complex thixotropy with increasing of pH in the range of pH 3.70-11.96.     

类水滑石/蒙脱土体系的特殊粘弹性和触变性研究

本文对由类水滑石（HTlc） /钠质蒙脱土（MT）组成的复杂体系的粘弹性和触变性进行了详细的研究,我们共研究了两种Fe-Mg-Al- HTlc样品,从样品1到样品2,Al 对 Fe的比例保持不变,而Mg2+的含量逐渐增加。研究发现,随着类水滑石中Mg2+的含量增加,HTlc/MT分散体系的结构强度逐渐增加;触变环的实验结果也表明,随着类水滑石中Mg2+的含量增加,HTlc/MT分散体系的触变程度逐渐增加。由此我们可以得到这样的结论,通过调节类水滑石金属的配比我们就可以对类水滑石/蒙脱土体系的流变性进行宏观的调节。