Effect of aging time on the rheology of Laponite dispersions
Effect of aging time on the rheology of Laponite dispersions
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DOI：
10.1016/j.colsurfa.2008.06.035
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发表时间：
2008-10
期刊：
影响因子：
--
通讯作者：
J. Labanda;J. Llorens
中科院分区：
文献类型：
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作者：
J. Labanda;J. Llorens
通过流变测量分析老化时间对含有聚丙烯酸钠的Laponite水性分散体的影响。通过振荡实验和流动实验测定了这些分散体的流变行为。聚丙烯酸钠的加入改变了Laponite颗粒之间的相互作用，因此改变了分散体的物理状态。作为聚丙烯酸钠浓度的函数的Laponite分散体的相图显示对于特定Laponite浓度的不同溶胶-凝胶转变。随着老化时间的延长，过渡线走向较低的Laponite浓度。的结构模型允许的表征Laponite分散体的触变性的装置的内部结构的对齐所施加的剪切速率和净击穿和建设过程的触变性时间。在聚丙烯酸钠存在下分散体的触变性较少依赖于老化时间，表明聚丙烯酸钠降低了三维网络形成的聚集速率，并允许更好地控制流变学，至少在分散体制备后12天。
The effect of aging time on aqueous Laponite dispersions containing sodium polyacrylate was analyzed by rheometric measurements. The rheological behavior of these dispersions was determined by oscillatory and flow experiments. Addition of sodium polyacrylate modifies the interactions between Laponite particles and, therefore, the physical state of the dispersion. The phase diagram of Laponite dispersions as a function of sodium polyacrylate concentration shows different sol–gel transitions for a specific Laponite concentration. The transition line goes to lower Laponite concentrations with aging time. A structural model permitted the characterization of the thixotropy of Laponite dispersions by means of the alignment of the internal structure to the applied shear rate and by the thixotropic times of the net breakdown and buildup processes. The thixotropy of dispersions in presence of sodium polyacrylate was less dependent on aging time, indicating that sodium polyacrylate reduces the aggregation rate of the formation of a three-dimensional network and permits better control of rheology, at least for 12 days after the preparation of dispersion.