[open quotes]Inverse[close quotes] organic-inorganic composite materials. 3. High glass content [open quotes]nonshrinking[close quotes] sol-gel composites via poly(silicic acid esters)
- Lawrence Berkeley Lab., CA (United States)
A critical challenge in the design of inorganic-organic composites is control over the mixing between the two chemically dissimilar phases. The sol-gel process has been utilized for the homogeneous incorporation of organic 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. The authors 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 their initial reports on the use of these new sol-gel precursors for the production of nonshrinking sol-gel composites, they have focused their efforts toward the synthesis and application of poly(silicic acid esters) bearing the same polymerizable alkoxides. This new approach allows for the synthesis of nonshrinking 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 3,000 to 30,000 simply by increasing the reaction time of the silicic acid synthesis. Also, particle shape can be controlled by the pH of the reaction solution. A modified esterification process using THF or benzene for azeotropic removal of water has been developed for synthesizing poly(silicic acid esters) with thermally unstable unsaturated alcohols. These substituted poly(silicic esters) have been used to produce transparent nonshrinking composites with a wide range of glass/polymer ratios. 15 refs., 2 figs., 5 tabs.
- OSTI ID:
- 5865826
- Journal Information:
- Chemistry of Materials; (United States), Journal Name: Chemistry of Materials; (United States) Vol. 5:6; ISSN CMATEX; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
Similar Records
Sol-gel-based inorganic-organic composite materials
Better ceramics through chemistry III; Proceedings of the Symposium, Reno, NV, Apr. 5-9, 1988
Related Subjects
360601 -- Other Materials-- Preparation & Manufacture
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALKOXIDES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COMPOSITE MATERIALS
GLASS
HYDRIDES
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INORGANIC POLYMERS
MATERIALS
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
PH VALUE
POLYMERIZATION
POLYMERS
SHRINKAGE
SILANES
SILICIC ACID
SILICON COMPOUNDS
SOL-GEL PROCESS
SYNTHESIS