Structure-property behaviour of hybrid materials incorporating tetraethoxysilane with multifunctional poly(tetramethylene oxide)

Polytetramethylene oxide based polyurethane oligomers with multiple triethoxysilane groups have been successfully incorporated into a TEOS based silicate network. It is observed that the incorporation of these oligomeric compounds was enhanced by the presence of additional functional groups along their backbone. The materials produced showed significant improvement in both tensile modulus and strength over previous organic-inorganic hybrid systems. As the number of functional groups per molecule increased, the stiffness of the material increased and the oligomeric Tg shifted to higher temperatures. Also, the SAXS correlation distance decreased systematically. A schematic model suggested previously can still be used to interpret these results. Other effects of TEOS content and ageing are also reported and discussed.