Chapter 29. Silsesquioxanes as Precursors to Ceramic Composites
- William Smothers
Published Online: 26 MAR 2008
Copyright © 1987 The American Ceramic Society, Inc.
11th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 8, Issue 7/8
How to Cite
Hurwitz, F. I., Hyatt, L., Gorecki, J. and D'Amore, L. (1987) Silsesquioxanes as Precursors to Ceramic Composites, in 11th Annual Conference on Composites and Advanced Ceramic Materials: Ceramic Engineering and Science Proceedings, Volume 8, Issue 7/8 (ed W. Smothers), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470320402.ch29
- Published Online: 26 MAR 2008
- Published Print: 1 JAN 1987
Print ISBN: 9780470374733
Online ISBN: 9780470320402
Silsesquioxanes having the general structure RSiO1.5, where R = methyl, propyi or phenyl, melt flow at 70°–100°C. Above 100°C, free-OH groups condense. At 225°C further crosslinking occurs, and the materials form thermosets. Pyrolysis, with accompanying loss of volatiles, takes place at nominally 525°C. At higher temperatures, the R group serves as an internal carbon source for carbothermal reduction to SiC accompanied by the evolution of CO. By bending Silsesquioxanes with varying R groups, both the melt rheology and composition of the fired ceramic can be controlled. Fibers can be spun from the melt which are stable in argon to 1400°C. The silsesquioxanes also have been used as matrix precursors for Nicalon and α-SiC platelet reinforced composites.