Sol-gel polymerization studied through sup 29 Si NMR with polarization transfer

Journal Article · Wed Jan 23 23:00:00 EST 1991 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100155a082· OSTI ID:5853900

Brunet, F; Cabane, B; Dubois, M; Perly, B ^[1]

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1. Commissariat a l'Energie Atomique, Gif-sur-Yvette (France)

Silicon tetramethoxide (TMOS) monomers have been dissolved in mixtures of methanol and water, hydrolyzed, and condensed to form siloxane polymers. The various oligomers which form during the early stages of the reaction have been identified through high-resolution {sup 29}Si NMR with polarization transfer. At low water/alkoxide ratios the hydrolysis is incomplete and limits the condensation reaction. Small cyclics are formed in addition to linear polymers. At high water/alkoxide ratios, the hydrolysis is fast and complete and the condensation is rate limiting. The polymers are largely branched as indicated by the high proportion of Q{sup 3} chain branching sites and Q{sup 4} three dimensionally cross-linked groups. So highly condensed species including small rings or cagelike structures can be expected in these mixtures.

• OSTI ID: 5853900
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 95:2; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
360602 -- Other Materials-- Structure & Phase Studies
ALCOHOLS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
METHANOL
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLYMERIZATION
RESONANCE
SILICON 29
SILICON COMPOUNDS
SILICON ISOTOPES
SILICON OXIDES
SOL-GEL PROCESS
STABLE ISOTOPES
WATER