2017 Volume 71 Issue 1 Pages 478-485
This paper describes the influence of Ca ion concentration in a liquid phase for the adsorption conformation of polycarboxylate-based dispersant（PC）with different numbers of ethylene oxide units per side chain（n＝9, 23, 45）. As an index of adsorbed PC conformation, Occupied area per a PC molecular is calculated by the data of PC adsorption experiment which Morita and Ando conducted by using calcite and α-Al2O3 as adsorbents. We construct the adsorption model to estimate occupied area per a PC molecular by using K, is the ratio of horizontally length in lengthened side chain to original side chain length. As a result, the plane area that side chain occupies with increase in Ca ion concentration in a liquid phase is smaller. The extension of side chain promoted for a liquid phase direction produced thicker adsorbed layer of PC. K calculated from this model suggests that PC with short side chain exhibits a double-layer adsorption because of hydrophobic interaction between short side chains. This causes thicker adsorbed layer than side chain length. This paper can explain that the adsorption conformation of PC changes by a difference of specific adsorption ion concentration in a liquid phase when we use the same PC with the adsorbents which do not show a hydration reaction.
