F. Babonneau et J. Maquet, Nuclear magnetic resonance techniques for the structural characterization of siloxane-oxide hybrid materials, POLYHEDRON, 19(3), 2000, pp. 315-322
The objective of this paper is to discuss the appropriateness of various so
lution and solid state NMR techniques to describe structural aspects of sil
oxane-oxide hybrid systems prepared by sol-gel processes. Co-hydrolysis of
organosilanes and metallic alkoxides can promote either self-condensation o
r co-condensation reactions between the different precursors, and this will
control the structural homogeneity of the final network. Solution state Si
-29 and O-17 NMR can give unique information on the formation and stability
of co-condensing species. In the final gels, solid state Si-29 MAS used in
conjunction with cross-polarization (CP) and related two-dimensional Si-29
-H-1 heteronuclear NMR correlation techniques, provides detailed informatio
n on dipole-dipole coupled Si-29 and H-1 species among different molecular
moieties. Finally, the use of O-17 MAS NMR with the newly developed MQ MAS
sequence that provides a direct identification of the various oxo bridges w
ill be discussed. (C) 2000 Elsevier Science Ltd All rights reserved.