Abstract

The characterization of the rheological behaviors of polymer-surfactant binary mixtures is important in several applications and industrial processes. In this paper, rheological behaviors of partially hydrolyzed polyacrylamide (PHPAM) polymer and sodium dodecyl sulfate (SDS) surfactant solutions have been investigated through viscosity measurement and then mathematical regression modeling. The effects of salt (CaCl₂) and alkali (NaOH) on the viscosities of these polymer-surfactant solutions have also been experimentally investigated and theoretically modeled. All polymer-surfactant systems are found to exhibit shear-thinning non-Newtonian behavior. The experimental investigations revealed that addition of salt extensively reduced the viscosity of polymer-surfactant solutions by reducing the hydrodynamic size of polymer and this peculiar effect has been explained in terms of electrical double layer (EDL). The non-Newtonian polymer-surfactant solutions became almost Newtonian when the concentration of CaCl₂ exceeded some threshold value (≥4.5 × 10⁻²mol.L⁻¹ or 0.5 wt%). Presence of NaOH also reduced the viscosity significantly and explained using the theory of molecular dynamics. The Herschel–Bulkley power law model through mathematical regression fitting procedure has been used to estimate the yield stress (τ⁰), the consistency index (k) and the flow behavior exponent (n) and analyze the rheology results.

摘要

聚合物-表面活性剂二元混合物的流变行为表征在多种应用和工业过程中非常重要。本文通过粘度测量和数学回归建模研究了部分水解聚丙烯酰胺 (PHPAM) 聚合物和十二烷基硫酸钠 (SDS) 表面活性剂溶液的流变行为。盐的影响（CaCl ₂) 和碱 (NaOH) 对这些聚合物-表面活性剂溶液的粘度的影响也进行了实验研究和理论建模。发现所有聚合物-表面活性剂系统都表现出剪切稀化的非牛顿行为。实验研究表明，盐的添加通过降低聚合物的流体动力学尺寸，大大降低了聚合物-表面活性剂溶液的粘度，这种特殊的效果已经用双电层 (EDL) 来解释。当 CaCl ₂的浓度超过某个阈值（≥4.5 × 10 ^-2 mol.L ^-1或 0.5 重量％）。NaOH 的存在也显着降低了粘度，并使用分子动力学理论进行了解释。通过数学回归拟合程序的 Herschel-Bulkley 幂律模型已用于估计屈服应力 ( τ ⁰ )、稠度指数 ( k ) 和流动行为指数 ( n ) 并分析流变学结果。