胶质液体泡沫的流变性

应用RV-30旋转粘度计和锥板式RS300应力控制流变仪, 采用稳态剪切方法和小振幅振荡剪切对胶质液体泡沫(CLA)体系的流变特性进行了系统分析, 讨论了温度、 相体积比(油相与水相体积比, PVR)和剪切速率对体系流变性质的影响. 稳态剪切实验结果表明, CLA体系表现出非牛顿流体特征, 其流变行为符合Herschel-Bulkley流变模式. 同时, CLA体系表现出剪切稀释特性, 不具有触变性. 粘弹性实验结果表明, 在低PVR(PVR=2~4)条件下, CLA无线性粘弹性区; 当PVR=8时, 表现出一定程度的粘弹性; 温度对体系的流变行为和粘弹性的影响不显著. 通过与高内相乳状液(HIPRE)体系比较, 发现CLA与HIPRE具有相似的流变特性, 这也说明两者在微观结构上具有一定的相似性.

Rheological Properties of Colloidal Liquid Aphrons

Colloidal liquid aphrons(CLA)composed of polyoxyethylene 3 dodecyl ether(AEO-3)/n-decane/sodium dodecyl sulphate(SDS)/water were subjected to a full rheological characterization.Steady-state flow and dynamic viscoelasticity were measured via a Haake RV-30 viscosimeter and a controlled stress rheometer Haake RS 300 with cone-plate geometry,respectively.The effects of the volume ratio of dispersed oil phase to the continuous phase(PVR),temperature and shear rate on the rheological behavior of CLA were also discussed.The results of the steady-state analysis indicate that both CLA and emulsions studied here were typical non-Newtonian liquids and exhibited strong shear thinning behavior.The flow curves of CLA were well described by the Hershel-Bulkley equation.Thixotropy was not observed in any of CLA and emulsions.The findings from the oscillatory viscoelastic analysis suggest that no linear viscoelasticity region existed in the entire range of stresses for low PVR(2-4),and at the PVR of 8,the systems display a viscoelastic behavior.The effect of temperature on the flow behavior and viscoelasticity of CLA and emulsions was not evident.The rheological properties of CLA are analogous to that of high internal phase ratio emulsions(HIPRE)through a comparison of the findings throughout this work and conclusions of HIPRE reported previously.This similarity further suggests that CLA and HIPRE display a similar microstructure.