Chapter 7. Suspension of Sic Powders in Allylhydridopolycarbosilane (Ahpcs): Control of Rheology

  1. Todd Jessen and
  2. Ersan Ustundag
  1. Frances I. Hurwitz

Published Online: 28 MAR 2008

DOI: 10.1002/9780470294635.ch7

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4

24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4

How to Cite

Hurwitz, F. I. (2008) Suspension of Sic Powders in Allylhydridopolycarbosilane (Ahpcs): Control of Rheology, in 24th Annual Conference on Composites, Advanced Ceramics, Materials, and Structures: B: Ceramic Engineering and Science Proceedings, Volume 21, Issue 4 (eds T. Jessen and E. Ustundag), John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9780470294635.ch7

Author Information

  1. NASA Glenn Research Center Lewis Field Cleveland, OH 44135

Publication History

  1. Published Online: 28 MAR 2008
  2. Published Print: 1 JAN 2000

ISBN Information

Print ISBN: 9780470375693

Online ISBN: 9780470294635

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Keywords:

  • preceramic polymers;
  • AHPCS polymer;
  • thermal conductivity;
  • starfire systems;
  • low viscosities

Summary

Inert particulate fillers can be blended with preceramic polymers prior to infiltration of composite preforms to increase pyrolysis yield and decrease shrinkage, thus reducing the number of infiltration/ pyrolysis cycles required for densification. However, particulate filler loadings and concentration of added dispersants necessary to maintain low viscosity (< 0.50 N s /m2) slurries vary with the characteristics of the particular AHPCS polymer batch. These batch to batch variations occur with alterations in the synthesis process and method of allyl substitution, which in turn alter polymer structure and molecular weight distribution. A number of different polymer batches were characterized by NMR, GPC and thermal analysis, and the influence of polymer structure on rheology of filled systems determined. When the high molecular weight fraction increased to too great a level, suitably fluid slurries could no longer be attained.