Inverse Organic-Inorganic Composite Materials. 3. High Glass Content Non-Shrinking Sol-Gel Composites via Poly(silicic acid esters). (Reannouncement with New Availability Information)

摘要

The sol-gel process has been utilized for the homogeneous incorporation oforganic polymers into an inorganic matrix. One major limitation in the synthesis of sol-gel composites is the ubiquitous shrinkage that results from the evaporation of excess solvents and water. In our research, we have attempted to address this issue by developing in situ, synchronous polymerization routes into these hybrid materials through the use of tetraalkoxysilanes possessing polymerizable alkoxides. Since our initial reports on the use of these new sol-gel precursors for the production of non-shrinking sol-gel composites, we have focused our efforts towards the synthesis and application of poly(silicic acid esters) bearing the same polymerizable alkoxides. This new approach allows for the synthesis of non-shrinking sol-gel composites with higher glass content than was previously possible with the tetraalkoxysilane derivatives. Furthermore, the use of poly(silicic acid esters) provides a new means for controlling composite morphology through the size and shape of the poly(silicic acid ester). Molecular weights for these poly(silicic acid esters) can be varied from 5,000 to 2,000,000 simply by increasing the reaction time of the silicic acid synthesis. Also, particle shape can be controlled by the pH of the reaction solution. Interpenetrating networks, Organic-inorganic composites, Sol-gel.