PREPARATION AND SI-29 NMR SPECTROSCOPIC INVESTIGATION OF POLYMERS WITH DEFINITE SILICIC-ACID UNITS

Three polymers were synthesized by additive reaction of the cage-like double four-ring (D4R) silicic acid derivatives [(CH3)2HSi]8Si8O20 and [CH2 = CH(CH3)2Si]8Si8O20 resp., with the unsaturated divinyltetramethyldisiloxane or the multiple functional tetramethylcyclotetrasiloxane and polymethylhydrogensiloxane [GRAPHICS] in a molar ratio of functional groups 1:1. By means of Si-29 solid state NMR spectroscopy was shown that the in organic solvents insoluble polymers are built up by D4R silicic acid units, which are connected by chain-like or cyclic siloxane bridges. With increasing functional groups of the reactants the sterical hindrance of the reaction of D4R derivates grows. The polymers show small surfaces of 1 to 8 m2/g.