A Solid State Multinuclear Magnetic Resonance Study of the Sol-Gel Process using Polysilicate Precursors

1986 ◽  
Vol 73 ◽  
Author(s):  
W. G. Klemperer ◽  
V. V. Mainz ◽  
D. M. Millar
Keyword(s):  
Solid State ◽  
Magnetic Resonance ◽  
Sol Gel ◽  
Building Blocks ◽  
Magnetic Resonance Study ◽  
Solvent Content ◽  
Molecular Building Blocks ◽  
Nmr Study ◽  
Sol Gel Process ◽  
Nmr Techniques

ABSTRACTA solid state multinuclear NMR study of the sol-gel process was performed using the molecular building blocks tetramethoxysilane, hexamethoxydisiloxane, octamethoxytrisiloxane and octamethoxyoctasilsesquioxane as precursor monomers. Water content, solvent content, and hydrolysis/condensation processes were monitored using 17O, 13C, and 29Si FT, FTMAS and CPMAS NMR techniques.

Molecular Building Blocks in Low PH Silicon Sol-Gels: A Silicon-29 NMR Study

1988 ◽  
Vol 121 ◽  
Author(s):  
Larry W. Kelts ◽  
Nancy J. Armstrong
Keyword(s):  
Sol Gel ◽  
Building Blocks ◽  
Low Ph ◽  
Tetraethyl Orthosilicate ◽  
Compact Ring ◽  
Molar Ratios ◽  
Molecular Building Blocks ◽  
Nmr Study ◽  
Ring Structures ◽  
Silicon Sol

ABSTRACTHigh field Silicon-29 NMR is used to study the structural intermediates in tetramethyl and tetraethyl orthosilicate (TMOS and TEOS) low pH sol-gel reactions. Linear oligomers as well as ring components of various sizes are identified and their evolution in the sols is followed. Differences in the number of compact ring structures are related to differences in gel times. Reactions are followed for various silicon alkoxide:water:acid molar ratios.

The use of multinuclear solid state NMR for the characterization of siloxane-oxide hybrid nanocomposites

2004 ◽  
Vol 847 ◽  
Author(s):  
Christel Gervais ◽  
Beatriz Julián ◽  
Eloisa Cordoncillo ◽  
Purificación Escribano ◽  
Mark E. Smith ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Sol Gel ◽  
Hybrid Nanocomposites ◽  
Sol Gel Process ◽  
Hydrolysis And Condensation ◽  
Silicon Alkoxides ◽  
Different Types ◽  
Nmr Techniques

ABSTRACTThe objective of this paper is to review various solid state NMR techniques that have been, or can be used for the structural characterization of siloxane—oxide hybrid systems prepared by sol-gel process, and to discuss the type of information they provide, as well as their limitations. More precisely, this paper focuses on NMR techniques to probe and quantify the different types of oxo-bridges (M–O–M of oxide network, Si–O–Si of siloxane chains and Si–O–M siloxane–MxOy interface) in siloxane-oxide nanocomposites prepared through hydrolysis and condensation of organosilanes and M(OR)n alkoxides. In addition the influence of the functionality of the silicon alkoxides and the nature of the MxOy oxides on the extent of the Si-O-M interface will be examined.

Polynuclear Titanium Oxoalkoxides: Molecular Building Blocks for New Materials?

1992 ◽  
Vol 271 ◽  
Author(s):  
Y. W. Chen ◽  
W. G. Klemperer ◽  
C. W. Park
Keyword(s):  
Solid State ◽  
Metal Oxide ◽  
Good Yield ◽  
Sol Gel ◽  
Building Blocks ◽  
Mas Nmr ◽  
Core Structure ◽  
New Materials ◽  
Molecular Building Blocks

ABSTRACTThe [Ti7O4](OEt)20 molecule, Et = C2H5, is very reactive toward ethanol, and its [Ti7O4] metal oxide core structure is largely decomposed in <10 minutes. The [Ti16O16](OEt232 molecule, however, has a [Ti16O16] core structure which is relatively stable toward alcoholysis, and solid state 17O MAS NMR experiments using selective 17O labeling techniques show that this core structure is preserved in good yield during sol-gel polymerization.

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