Rheological Behavior of Aqueous Solutions of Cationic Guar in Presence of Oppositely Charged Surfactant  

在相反电荷表面活性剂存在下阳离子瓜尔胶水溶液流变行为

作　　者：李化真[1] 杨海洋[1] 谢永军[1] 李化玉[1] 何平笙[1] 

机构地区：[1]中国科学技术大学高分子科学与工程系,合肥230026

出　　处：《Chinese Journal of Chemical Physics》2010年第4期491-496,I0002,共7页化学物理学报（英文）

摘　　要：The cationic guar （CG） is synthesized and the rheological behavior of aqueous solutions of CG in the presence of sodium dodecyl sulfate （SDS） is studied in detail. The steady viscosity measurements show that the zero shear viscosity enhancement can be almost 3 orders of magnitude as the concentration of SDS increases from 0 to 0.043%. The gel-like formation is observed as the concentration of SDS is greater than 0.016%. The oscillatory rheological measurements of CG solutions in the presence of SDS show that the crossover modulus is almost independent of the concentration of SDS whereas the apparent relaxation time increases swiftly upon increasing the concentration of SDS. The experimental results indicate that the strength rather than the number of the cross-links is greatly affected by SDS molecules. The mechanism concerning the effect of SDS upon the rheology of CG solutions can be coined by the two-stage model. Before the formation of cross-links at the critical concentration, the electrostatic interaction between SDS and cationic site of CG chains plays a key role and the SDS molecules bind to CG chains through the electrostatic interaction. After the formation of cross-links at the concentration greater than the critical concentration, the cooperative hydrophobic interaction become dominant and SDS molecules bind to the cross-links through the hydrophobic interaction. The theological behavior of aqueous solutions of CG in the presence of SDS is chiefly determined by the micelle-like cross-links between CG chains. In fact, the flow activation energy of CG solution, obtained from the temperature dependence of the apparent relaxation time, falls in the range of transferring a hydrophobic tail of SDS from the micelle to an aqueous environment.

关 键 词：Cationic guar Sodium dodecyl sulfate Rheological behavior Relaxation time Zero-shear viscosity 

分 类 号：O[理学]