Inorganic-organic polymers derived from functional silicic acid derivatives by additive reaction

Abstract

Inorganic-organic polymers were synthesized by additive reaction of vinyl-, allyl-, and H-silylated double four-ring (D4R) silicic acids and polymeric silicic acids. The structure and properties of the hybrid polymers were investigated by means of 29Si NMR spectroscopy, thermoanalysis and BET nitrogen adsorption measurements. Using the defined vinylsilylated D4R silicicacid [(CH2=CH)(CH3)2Si]8Si8O20 and the corresponding H-silylated compound [(CH3)2HSi]8Si8O20 as precursors, the additive reaction results in a microporous polymer with a ordered Si8O20 substructure. The structural units are connected by six-membered bridges. Shorter (four-membered) or longer (seven-membered) bridges between D4R cages lead to non-porous polymeric materials. The connection of water-glass-derived silicic acid units by six-membered bridges similarly leads to porous polymers with specific surface areas of 500 m2/g. For the preparation of the porous hybrid polymers a new, simple two-step reaction route is described.