Magnetohydrodynamic mixing was evaluated as an alternative to conventional high shear mixing (HSM) in the preparation of carbomer hydrogels containing 1.22 wt% Carbopol® 980 NF. Neutralization of the carbomer dispersion (pH = 2.74) with triethanolamine (TEA) enabled to adjust the pH of the mixture and tune the viscosity of the hydrogel. Using HSM, this approach was limited to 0.2 wt% TEA (pH = 3.83) as the gel became too viscous and the recirculation flow dropped from 12 to 0.3 m³/h. Magnetohydrodynamic mixing enabled to reach TEA concentrations up to 1.0 wt% (pH = 5.31). Apparent viscosity measurements on samples having 0.2 wt% TEA revealed lower viscosities for carbomer hydrogels prepared with HSM, that is, 6800 mPa s versus 8800 mPa for magneto-hydrodynamic mixing. Based on ¹H NMR evidence, this decrease in apparent viscosity was attributed to structural damage to the carbomer backbone in combination with mechanochemical degradation of the added TEA.

中文翻译：

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磁流体动力混合：一种制备卡波姆水凝胶的新技术

在制备含有 1.22 wt% Carbopol® 980 NF 的卡波姆水凝胶时，磁流体动力混合作为传统高剪切混合 (HSM) 的替代方法进行了评估。用三乙醇胺 (TEA) 中和卡波姆分散体 (pH = 2.74) 可以调节混合物的 pH 值并调节水凝胶的粘度。使用 HSM，该方法限于 0.2 wt% TEA (pH = 3.83)，因为凝胶变得太粘并且再循环流量从 12 下降到 0.3 m ³ /h。磁流体动力混合能够使 TEA 浓度达到 1.0 wt% (pH = 5.31)。对具有 0.2 wt% TEA 的样品进行的表观粘度测量显示，用 HSM 制备的卡波姆水凝胶的粘度较低，即 6800 mPa s 与磁流体动力混合的 8800 mPa 相比。基于¹H NMR 证据表明，这种表观粘度的降低归因于卡波姆主链的结构损坏以及添加的 TEA 的机械化学降解。