【摘要】 研究了铝 /镁混合金属氢氧化物 ( MMH)粒子含量、p H值、电解质等因素对 MMH悬浮体流变学的影响 ,发现 MMH粒子浓度的增加使悬浮体从牛顿型流体变为带有屈服值的假塑性流体 ;在相对很低的粒子浓度 ( 2 % )时 ,通过改变粒子表面化学状态和粒子周围的介质环境可以改变悬浮体的流动形态 ;MMH悬浮体触变性结构与高 p H值时合成锂皂石悬浮体的结构极为相似 ,是粒子间的静电排斥作用所致 .更多还原

【Abstract】 The rheology of aqueous Al Mg MMH(mixed metal hydroxide) dispersions and electrophoretic mobility of MMH colloidal particles were studied by rheological and electrokinetic measurements as a function of MMH concentration, pH of dispersion and NaCl concentration. It was found that the suspensions are Newtonian at low MMH concentrations, while increasing MMH concentration gives rise to the suspensions with a yielding type of behavior. However, a transition from Newtonian to non Newtonian flow curves may occur at relatively low MMH concentration(2%) when suspensions was formulated near the isoelectric point(pH iep) for MMH or with NaCl being added to MMH suspensions below pH iep. It appears that the rheology of MMH dispersions is closely correlated to the MMH concentration and the surface charge of MMH particle. When the recovery experiments with a relatively high vigorous stirring and at a low shear rate were performed on inherent MMH suspensions consisting of positively charged platelike particles, the evolution of the gel structure is very slow, similar to the result for aqueous Laponite system consisting of negatively charged platelike particles. This result suggests that it is also the long range electrostatic double layer forces that lead to the formation of a repulsive gel in MMH suspensions, similar to aqueous Laponite system at a high pH.更多还原