Sol-gel chemistry studied by 1H and 29Si nuclear magnetic resonance

Kelts, Larry W.; Effinger, N.J.; Melpolder, S. M.

doi:10.1016/0022-3093(86)90248-6

Cited by 199 publications

(89 citation statements)

References 8 publications

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“…14,15 The number x of Q x corresponds to the number of bridging oxygens per silicon. Peak intensities of Q 1 and Q 2 decrease while those of Q 3 and Q 4 increase with an increasing ratio of H 2 O/TEOS, suggesting that a silica network grows with increasing H 2 O concentration.…”

Section: Evoh-oh →mentioning

confidence: 99%

“…4 C-NMR measurements, respectively. It was assured that the addition of chromium acetylacetonate had no effect on the spectrum 11 and that the recycle times of 6 s for 29 Si and 10 s for 13 C were long enough for the quantitative analysis. The chemical shifts (␦, ppm) of 29 Si and 13 C relative to tetramethylsilane (␦ = 0 ppm) were determined by using peaks at 1.534 ppm for (CH 3 ) 3 Si(CH 2 ) 3 SO 3 Na and at 176.46 ppm for the carboxyl carbon in glycine as respective external references.…”

Section: Analysis Of Surface Structure and Teos Solutionmentioning

confidence: 99%

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Apatite formation on ethylene-vinyl alcohol copolymer modified with silanol groups

Oyane¹,

Minoda²,

Miyamoto³

et al. 1999

J. Biomed. Mater. Res.

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The surfaces of ethylene-vinyl alcohol copolymer (EVOH) substrates were modified with silanol (Si-OH) groups, and their apatite forming ability was examined in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma or in a solution with ion concentrations 1.5 times those of SBF (1.5SBF). The surface modification of EVOH was carried out by reacting 3-isocyanatopropyltriethoxysilane, followed by hydrolysis of the ethoxysilyl groups into Si-OH groups. However, no apatite formation was observed on the EVOH substrate thus modified, even after 3 weeks in SBF and 1.5SBF. The Si-OH modified EVOH substrate was further modified by hydrolysis and polycondensation of tetraethyoxysilane (TEOS). It was found that the apatite forms on the TEOS-modified substrate within 3 weeks in 1.5SBF. These results suggest that the presence of a large amount of Si-OH groups (i.e., a cluster of Si-OH groups) on the substrate is prerequisite to apatite formation in the body environment. Apatite-EVOH composites prepared by this process might be useful as hard tissues substitutes.

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Section: Evoh-oh →mentioning

confidence: 99%

Section: Analysis Of Surface Structure and Teos Solutionmentioning

confidence: 99%

Apatite formation on ethylene-vinyl alcohol copolymer modified with silanol groups

Oyane¹,

Minoda²,

Miyamoto³

et al. 1999

J. Biomed. Mater. Res.

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“…The advantage of the sol-gel technique for preparing hybrid materials is the low reaction temperature required (e.g. room temperature) which enables the incorporation of inorganic elements into organic materials without deterioration of their functionality [4][5][6][7][8]. The sol-gel method consists of an initial hydrolysis reaction and a subsequent condensation and then removal of the solvents, resulting in formation of a three-dimensional metal oxide network.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of hybrid organic–inorganic materials based on sulphonated polyamideimide and silica

et al. 2010

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Abstract:The preparation of hybrid organic-inorganic membrane materials based on a sulphonated polyamideimide resin and silica filler has been studied. The method allows the sol-gel process to proceed in the presence of a high molecular weight polyamideimide, resulting in well dispersed silica nanoparticles (<50nm) within the polymer matrix with chemical bonding between the organic and inorganic phases.Tetraethoxysilane (TEOS) was used as the silica precursor and the organosilicate networks were bonded to the polymer matrix via a coupling agent aminopropyltriethoxysilane (APTrEOS). The structure and properties of these hybrid materials were characterized via a range of techniques including FTIR, TGA, DSC, SEM and contact angle analysis. It was found that the compatibility between organic and inorganic phases has been greatly enhanced by the incorporation of APTrEOS.The thermal stability and hydrophilic properties of hybrid materials have also been significantly improved.

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“…Cr(acac) 3 has previously been used in similar sysin quantitativity problems, is negligible. tems, where it was shown that it does not interfere with the polyCalorimetric Study of the Complexation and Hydrolysis Reacmerization process [7] . tions: Four alkoxides were studied: Ti(OnBu) 4 , Ti(OEt) 4 , A second disadvantage of this nucleus is the presence of backTi(OiPr) 4 , Zr(OnPr) 4 .…”

mentioning

confidence: 99%

Hydrolysis and Condensation Reactions of Transition Metal Alkoxides: Calorimetric Study and Evaluation of the Extent of Reaction

Blanchard

Martin

Schaudel

et al. 1998

Eur. J. Inorg. Chem.

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The behavior of titanium and zirconium alkoxides towards complexation and water addition is analyzed through water titration and calorimetric experiments. A simple model is presented, which allows evaluation of the mean hydrolysis and condensation constants, Kh and Kc, of both pure and complexed transition metal alkoxides in the sol state, through the analysis of consumed water versus initial hydrolysis ratio curves. These constants allow comparison of the extents of the hydrolysis and condensation reactions for sols obtained from several alkoxide precursors. The complexation ratio only affects the condensation constant Kc, whereas the hydrolysis constant Kh remains unchanged. Analysis of the Kh/Kc ratios has shown that in the sol state, silanol Si–OH groups are more stable than the Ti–OH or Zr–OH groups. Moreover, this study has shown that the proton concentration not only affects the kinetics, but also the final composition of the system. Calorimetric studies of the complexation and hydrolysis/condensation reactions have highlighted the role of coordination unsaturation of the transition metal alkoxides in the exothermicity of these reactions, clearly demonstrating that coordination unsaturation is the driving force behind the reactivity of these alkoxides towards nucleophilic species (e.g. water, complexing ligands, polar solvents).

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Sol-gel chemistry studied by 1H and 29Si nuclear magnetic resonance

Cited by 199 publications

References 8 publications

Apatite formation on ethylene-vinyl alcohol copolymer modified with silanol groups

Apatite formation on ethylene-vinyl alcohol copolymer modified with silanol groups

Synthesis and characterization of hybrid organic–inorganic materials based on sulphonated polyamideimide and silica

Hydrolysis and Condensation Reactions of Transition Metal Alkoxides: Calorimetric Study and Evaluation of the Extent of Reaction

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