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Nmr Imaging of Silica-Silicone Composites

Published online by Cambridge University Press:  21 February 2011

Leoncio Garrido
Affiliation:
NMR Center, Massachusetts General Hospital, 149 13th St., Charlestown, MA 02129
Jerome L. Ackerman
Affiliation:
NMR Center, Massachusetts General Hospital, 149 13th St., Charlestown, MA 02129
James E. Mark
Affiliation:
Department of Chemistry and the Polymer Research Center, University of Cincinnati, Cincinnati, OH 45221
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Abstract

Polydimethylsiloxane (PDMS) model networks reinforced by in situ precipitated SiO2, and polymer-modified silica glasses were obtained following the usual sol-gel methods. The conditions were chosen to increase the probability of observing inhomogeneities: (i) bulky samples, and (ii) limited reaction times. These composites were characterized by measuring bulk spin-lattice (T1) and spin-spin (T2) relaxation times and using 1H NMR two-dimensional Fourier transform (2DFT) spin echo imaging techniques. The T1 and T2 maps show clear and significant variations of NMR signal intensity throughout the sample due to nonuniform hydrolysis of the tetraethylorthosilicate (TEOS) in the specimens.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

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References

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