温度和剪切协同作用对十六烷基三甲基氯化铵溶液表观黏度的 影响

深入研究表面活性剂的流变特性,对于理解湍流减阻机理和改进制药、化工等领域的产品质量具有重要意义。本文研究了相同升温速率、不同剪切速率以及相同剪切速率、不同升温速率对阳离子表面活性剂十六烷基三甲基氯化铵（CTAC）溶液表观黏度的影响。研究表明：当温度较低时,剪切速率对表面活性剂溶液表观黏度的影响起主导作用;随着温度的升高,高温对胶束的影响增强导致溶液在高温处出现剪切稀化现象。当浓度为0.3125mmol/L时,溶液临界温度随剪切速率的升高保持恒定;但当浓度升高至0.6250～1.2500mmol/L时,在高温和高剪切的作用下,黏度曲线出现“平台”和短暂的增稠现象。对于中等浓度表面活性剂溶液,浓度升高导致蠕虫状胶束出现分支并抑制了“平台”的产生;随着升温速率的增大,胶束结构的响应时间滞后于升温速率,但当γ=150s^?1时,滞后效应减弱,高剪切对胶束结构的破坏占主导作用。

Effect of synergistic effect of temperature and shear rate on apparent viscosity of cetyltrimethyl ammonium chloride solution

It is very important for studying the turbulence drag-reducing mechanism and improving product quality in the fields of pharmaceutical and chemical engineering to deeply investigate rheological properties of surfactants solution. Apparent viscosity on cationic surfactant cetyltrimethyl ammonium chloride (CTAC) solution was investigated for the same heating rate at different shear rates and for the same shear rate at various heating rates. The present results showed that the shear rate played a dominant role in the viscosity of surfactant solution when the temperature was low. With the increase of temperature, the influence of high temperature on micelles increased, resulting in shear-thinning phenomenon at the high temperature. When the concentration was 0.3125 mmo/L, the critical temperature of solution remained constant with increasing shear rate. However, when the concentration was 0.6250~1.2500 mmol/L, the viscosity curve appeared “platform” and transient thickening at the high temperature and the high shear. For the medium concentration solution, the increase of concentration led to the branch of wormlike micelles, which inhibited the formation of “platform”. With the increase of heating rate, the response rate of micellar structures lagged behind the heating rate. However, when γ=150s^-1, the hysteresis effect decreaseed and the destruction of micelle structure was dominated by the strong shear.