Author:

Keywords:

Science & Technology, Technology, Engineering, Chemical, Engineering, carbomer hydration, carbomer hydrogel preparation, high shear mixing, magneto-hydrodynamic mixing, nuclear magnetic resonance spectroscopy, RHEOLOGICAL PROPERTIES, CARBOPOL, DISPERSION, SHEAR, ERC SCIFY - 866070;info:eu-repo/grantAgreement/EC/H2020/866070, WATUSO - 834134;info:eu-repo/grantAgreement/EC/H2020/834134, METH/14/04#53291607, I001321N#56241633, 0904 Chemical Engineering, 0914 Resources Engineering and Extractive Metallurgy, Chemical Engineering, 4004 Chemical engineering

Abstract:

Abstract Magnetohydrodynamic mixing was evaluated as an alternative to conventional high shear mixing 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 high shear mixing, 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 high shear mixing, i.e. 6,800 mPa·s versus 8,800 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.