Absorption conformations in the intercalation process of polycarboxylate ether based superplasticizers into montmorillonite clay

Abstract

The intercalation of polycarboxylate based superplasticizers (PCE) into montmorillonite clay (MNT) is arranged preferably by two types of absorption conformations: one-to-one conformation and bridging conformation. A third model named plugged conformation is described but it seems not appropriate to polymers having anionic charge and it would be possible only for very particular cases. The preferred conformation of absorption of the PCE polymer is determined by key properties of the polymer and the clay. For the polymer, the two main characteristics are the length of side chains and the side chain density. For the MNT clay, the mains properties are the layer charge and to a lesser extent the morphology of the clay particle. PCE anionic charge is not a determining factor for the absorption conformation but is a key factor for the earlier saturation of the interlaminar space by intercalation. Since many variables are interplaying simultaneously and complementarily, the interaction process between PCE polymers and MNT clays is very complex that deserves further studies.