Synthesis, characterization and reaction behaviour of lamellar AFm phases with aliphatic sulfonate-anions

The addition of alkanesulfonates as admixtures to cementitious materials allows the formation of new lamellar phases (AFm), which was proofed by X-ray diffraction (XRD). The course of hydration was investigated by heat flow calorimetry.The layered structures of AFm phases are composed of brucite-like main layers and interlayers containing alkanesulfonate ions and additional H2O molecules. These structural not necessary H2O molecules release gradually at definite steps with increasing temperature. With varying relative humidity the layer thickness c′ of short aliphatic chained calcium aluminate alkanesulfonate hydrates changes considerably, whereas large organic molecules dominate the layer thickness of those with longer aliphatic chains. By means of the increase of layer thickness with increasing chain lengths it is possible to determine the tilt angles of the aliphatic chains in the interlayers.