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 ◽  
...  

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.

ChemInform ◽  
2007 ◽  
Vol 38 (49) ◽  
Author(s):  
Christian Bonhomme ◽  
Cristina Coelho ◽  
Niki Baccile ◽  
Christel Gervais ◽  
Thierry Azais ◽  
...  

2007 ◽  
Vol 40 (9) ◽  
pp. 738-746 ◽  
Author(s):  
Christian Bonhomme ◽  
Cristina Coelho ◽  
Niki Baccile ◽  
Christel Gervais ◽  
Thierry Azaïs ◽  
...  

2002 ◽  
Vol 82 (4) ◽  
pp. 183-196 ◽  
Author(s):  
Jingdong Mao ◽  
Weiguo Hu ◽  
Guangwei Ding ◽  
Klaus Schmidt-Rohr ◽  
Geoffrey Davies ◽  
...  

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1400 ◽  
Author(s):  
Robert Knitsch ◽  
Melanie Brinkkötter ◽  
Thomas Wiegand ◽  
Gerald Kehr ◽  
Gerhard Erker ◽  
...  

Modern solid-state NMR techniques offer a wide range of opportunities for the structural characterization of frustrated Lewis pairs (FLPs), their aggregates, and the products of cooperative addition reactions at their two Lewis centers. This information is extremely valuable for materials that elude structural characterization by X-ray diffraction because of their nanocrystalline or amorphous character, (pseudo-)polymorphism, or other types of disordering phenomena inherent in the solid state. Aside from simple chemical shift measurements using single-pulse or cross-polarization/magic-angle spinning NMR detection techniques, the availability of advanced multidimensional and double-resonance NMR methods greatly deepened the informational content of these experiments. In particular, methods quantifying the magnetic dipole–dipole interaction strengths and indirect spin–spin interactions prove useful for the measurement of intermolecular association, connectivity, assessment of FLP–ligand distributions, and the stereochemistry of adducts. The present review illustrates several important solid-state NMR methods with some insightful applications to open questions in FLP chemistry, with a particular focus on supramolecular associates.


2008 ◽  
Vol 11 (4-5) ◽  
pp. 387-397 ◽  
Author(s):  
Cristina Coelho ◽  
Thierry Azais ◽  
Christian Bonhomme ◽  
Laure Bonhomme-Coury ◽  
Cédric Boissière ◽  
...  

2017 ◽  
Vol 121 (25) ◽  
pp. 13823-13832 ◽  
Author(s):  
Mickaël Blais-Roberge ◽  
Silvia H. Santagneli ◽  
Sandra H. Messaddeq ◽  
Maxime Rioux ◽  
Yannick Ledemi ◽  
...  

1986 ◽  
Vol 73 ◽  
Author(s):  
W. G. Klemperer ◽  
V. V. Mainz ◽  
D. M. Millar

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.


2008 ◽  
Vol 396-398 ◽  
pp. 481-484
Author(s):  
Rodrigo Jiménez-Gallegos ◽  
L. Téllez-Jurado ◽  
Luis M. Rodríguez-Lorenzo ◽  
Julio San Román

This paper focuses on the preparation of siloxane-polyurethane hybrid materials using a sol-gel method. The global aim of the project is to tailor mechanical properties, degradability rate, bioactivity and biocompatibility to design scaffolds for musculoskeletal applications. A series of seven hybrid materials were synthesized with varying the proportion of polydimethylsiloxane (PDMS), and Polyurethane (PU). The organic part ratios (by weight) employed were (% PDMS:% PU) 30:0, 35:5, 20:10, 15:15, 10:20, 5:25, and 0:30. The organic part was reacted with constant 70 % TEOS to obtain the hybrid materials. A sol-gel process was selected for the synthesis of the hybrids. The characterization of materials was carried out by the fourier-infrared spectroscopy (FT-IR), x-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electronic microscopy (SEM) and proton nuclear magnetic resonance (1H-NMR) techniques in order to analyze the structure, microstructure and chemical composition of the hybrid materials. Gelification time depends on the proportion of PU used. When no PU is employed, the gel time is 8 hours but it rises up to 18 days for 30 % of polyurethane. Materials range from opaque to translucent but with a greater fragility for greater amounts of polyurethane. No differences in the bonding of materials could be appreciated.


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