Tetraethoxysilane-poly systems

Noell et al. reported the preparation of silica-poly(ether ether ketone) hybrid materials with improved physical properties.155 An amine-end-capped poly(ether ether ketone) was used to react with isocyanatopropyltriethoxysilane in tetrahydrofuran (THF). The triethylsilane-end-capped poly (ether ether ketone) was mixed with tetraethoxysilane (TEOS) in THF. Quantitative amounts of water were introduced into die system, and the mixture was reduxed at 80°C. The entire reaction mixture was allowed to further react in Tedon molds. Tough transparent materials were obtained by diis approach. 

In polycondensation systems, a poly(dimethylsiloxane) with hydroxy end-groups at either end and a viscosity of 10- to 10 mPa s is crosslinked with tetraalkoxysilanes, e.g. tetraethoxysilane, in the presence of a condensation-accelerating tin compound e.g. dibutyltin dilaurate. Since this hardening, in contrast with single component products, is not dependent upon water diffusion through the hardening mass, thick layers of such rubber systems can be crosslinked quickly and homogeneously. 

Recently, Reetz and others have published a number of studies showing that adding organically modified silanes (precursors), such as methyltrimethoxysilane or poly (dimethylsiloxane), to tetraethoxysilane (TEOS) during hydrolysis can produce a protein-doped organicinorganic hybrid material that is hydrophobic [1-7]. Systems already tested... 

Wu et al. (2011) studied the long-time behavior of the hydrolysis and condensation reaction of the tetraethoxysilane (TEOS) pre-solution at different pH values with and without addition of poly(ethylene glycol) (PEG) for various aging times using liquid H, C, and Si NMR spectroscopy. Domjan et al. (2010) analyzed proximity in a thermoresponsive host-guest gel system and the polymer-phenol distance using solid-state H- H CRAMPS NMR spectroscopy and rate matrix analysis. The best agreement between calculated and measured values was found with methyl-phenol and methyne-phenol distances 0.5 and 0.55 nm, respectively. 

---