用液相非稳态共沉淀法合成了Zn Al类水滑石(HTlc),研究了样品中n(Al)/n(Zn+Al)(x)和层间阴离子CO2-3对Zn Al HTlc化学组成、晶体结构和粒子形貌的影响。结果表明,当0 31≤x≤0 52时可得到单一的Zn Al Cl HTlc相;x≤0 25时有ZnO杂质相出现;x>0 52时样品主要以无定形物存在。x对晶胞参数a和c影响不大;与Cl-相比,层间CO2-3对a影响不大,使c值略有降低。透射电镜(TEM)结果表明,随每摩尔HTlc样品n(Zn)增加,Zn Al ClHTlc粒子六角形片状结构规则度增加。电子衍射图谱表明,所合成的HTlc样品均为六方晶系多晶结构物质。
The thixotropy of suspension, the rheological properties change with the increase of shear time, is a complicated rheological phenomenon. The shear thinning and the shear thickening phenomena, i.e ., positive thixotropy and negative thixotropy, were observed respectively in the previous studies. Recently we found a novel thixotropic phenomenon, described as "complex thixotropy", during studying the thixotropic phenomenon of magnesium aluminum hydroxide montmorillonite suspension. The study of thixotropy of the aqueous suspension consisting of magnesium aluminum hydroxide(Mg Al MMH)possessing permanent positive and Kaolinite possessing permanent negative charges is reported. The suspensions studied may display a positive thixotropy and complex phenomenon successively in various Mg Al MMH/kaolinite ratios 0-0.16 examined. The effect of shear rate( D L)used in measuring viscosity on the thixotropy of the suspension was investigated, and the mechanism of the thixotropy was discussed.
