Clay−Aminopropylsiloxane Compositions

The intercalation of a cubic octamer derived from the controlled hydrolysis of (3-aminopropyl)triethoxysilane with smectite clays has been studied. The organosilicon cubanes are adsorbed in amounts exceeding the cation exchange capacity of the mineral. The excess quantity is incorporated in the form of physically adsorbed ion pairs, [(H 3 N−Pr) 8 O 12 Si 8 ] (OH) 8 . The ion pair formation affects the basal spacings of the clay organosilicon compositions. Removal of the ion-paired cubes by water treatment reduces the d 001 spacing from 18 to 16 Å. Lower surface areas were found for the unwashed samples indicating stuffing of the galleries by the ion-paired cubes. The orientation of the ion-exchanged and physically adsorbed octameric organosilicates in the interlayer region is deduced from the XRD and infrared results. Calcination of the washed or unwashed phases gives silica pillared structures with d 001 spacings near 16 Å, with the washed phase showing the higher surface area.