Structural characterization of organically-modified porous silicates synthesized using CTA+ surfactant and acidic conditions

1999 ◽  
Vol 9 (1) ◽  
pp. 175-178 ◽  
Author(s):  
Florence Babonneau ◽  
Lorraine Leite ◽  
Stéphanie Fontlupt
Keyword(s):  
Structural Characterization ◽  
Organically Modified ◽  
Acidic Conditions

Synthesis and Structural Characterization of Organically-Modified Microporous Silicates

1998 ◽  
Vol 519 ◽  
Author(s):  
F. Babonneau ◽  
L. Leite ◽  
S. Fonlupt ◽  
F. Ribot ◽  
L. Bergogne ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Nitrogen Adsorption ◽  
Type I ◽  
Silicate Phase ◽  
Organically Modified Silicates ◽  
Bet Method ◽  
Organically Modified ◽  
Acidic Conditions ◽  
Hexagonally Ordered

AbstractOrganically-modified silicates have been synthesized from RSi(OEt)3 (R = CH3, C2H5, C8H17, CH2=CH, C6H5) and TEOS under acidic conditions, in the presence of cethyltrimethylammonium (CTAB). The introduction of RSiO1.5 units with R/Si =0.2, affects the ordering of the expected hexagonal silicate phase, except when R = C6H5. The sample containing phenyl functions was thus submitted to surfactant extraction; calcination at 350°C appears to be more efficient, and less disruptive for the network ordering than a washing procedure in ethanol. Nitrogen adsorption measurements on the hexagonally ordered calcined sample that still contains phenyl groups, yields a type I isotherm, typical of a microporous solid. BET method leads to a surface area of 1000 m2/g and a pore volume of 0.32 cm3/g.

Solvent-free dynamic nuclear polarization enhancements in organically modified mesoporous silica

2021 ◽  
Author(s):  
Marcos de Oliveira Jr. ◽  
Kevin Herr ◽  
Martin Brodrecht ◽  
Nadia Berenice Haro-Mares ◽  
Till Wissel ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Porous Materials ◽  
Structural Characterization ◽  
Dynamic Nuclear Polarization ◽  
High Field ◽  
Nuclear Polarization ◽  
Organically Modified ◽  
Field Dynamic ◽  
Free Dynamic

High-field Dynamic Nuclear Polarization is a powerful tool for the structural characterization of species on the surface of porous materials or nanoparticles. For these studies the main source of polarization...

scholarly journals Micro-structural Characterization of Inorganic Cryptomelane Nanomaterials Synthesized by Use of Controlled O2 and Cold Aging in Acidic Conditions

2006 ◽  
Vol 12 (S02) ◽  
pp. 740-741
Author(s):  
L Ma ◽  
T Hartmann ◽  
MA Cheney ◽  
N Birkner
Keyword(s):  
Structural Characterization ◽  
Acidic Conditions

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Structural characterization of pectin-bismuth complexes and their aggregation in acidic conditions

2020 ◽  
Vol 154 ◽  
pp. 788-794 ◽  
Author(s):  
Wen-xin Jiang ◽  
Jun-Ru Qi ◽  
Jin-song Liao ◽  
Zhi-li Wan ◽  
Wan-ling Liang ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Acidic Conditions

Structural Characterization of Gels Prepared from Co-Hydrolysis of Tetraethoxysilane and Dimethyldiethoxysilane.

1992 ◽  
Vol 271 ◽  
Author(s):  
Florence Babonneau ◽  
Laurence Bois ◽  
Jacques Livage
Keyword(s):  
Structural Characterization ◽  
Silica Gels ◽  
Condensation Process ◽  
Modified Silica ◽  
Polymeric Gels ◽  
Organically Modified ◽  
Organically Modified Silica ◽  
Hydrolysis Of ◽  
Modified Silica Gels

ABSTRACTThis work is part of a more general study on the structural characterization of organically modified silica gels that are usually prepared from tetrafunctional, trifunctional and difunctional alkoxides. The systems that were investigated in this paper are gels prepared from co-hydrolysis of dimethyldiethoxysilane (DEDMS) and tetraethoxysilane (TEOS). The condensation process was followed by 29Si and 17O liquid NMR and shows clearly evidence for co-condensation reactions. Gels with various DEDMS/TEOS ratios were studied by 29Si and 1H MAS-NMR. The results are clearly correlated to the change in physical properties of the materials, from flexible polymeric gels at high DEDMS content to crosslinked brittle networks at low DEDMS content.

Structural characterization of three organically modified Cd(II) compounds

2011 ◽  
Vol 14 (10) ◽  
pp. 1681-1684 ◽  
Author(s):  
Juan Jin ◽  
Ming-Jun Jia ◽  
Yu-Chang Wang ◽  
Jie-Hui Yu ◽  
Qing-Feng Yang ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Organically Modified

New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques

1990 ◽  
Vol 48 (3) ◽  
pp. 582-583
Author(s):  
S. F. Hayes ◽  
M. D. Corwin ◽  
T. G. Schwan ◽  
D. W. Dorward ◽  
W. Burgdorfer
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Structural Characterization ◽  
Negative Staining ◽  
Low Speed ◽  
Thin Sectioning ◽  
Ultrastructural Findings

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.

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