About this Abstract |
Meeting |
MS&T21: Materials Science & Technology
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Symposium
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Preceramic Polymers; Synthesis, Processing, Modeling, and Derived Ceramics
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Presentation Title |
Effect of Pendant Groups on the Mass Yield, Density and Process Modeling of Polycarbosilanes during Pyrolysis |
Author(s) |
Thomas S Key, Garth B. Wilks, Michael K. Cinibulk |
On-Site Speaker (Planned) |
Thomas S Key |
Abstract Scope |
As preceramic are pyrolyzed, they undergo multiple thermal decomposition reactions. Differences in initial composition leads to differences in thermal decomposition of the polymers. These differences then affect the evolution of density of the polymers in a ways that dramatically affect their volume yield as a function of pyrolysis temperature. Experimental data indicated that the material models addressing volumetric changes during pyrolysis must be able to address both the temperature and time at temperature dependent changes in mass and material density, because density is not a simple function of mass yield. The model analysis of the materials performance revealed two major spikes in the rate of volume shrinkage where the first is initially driven by changes in mass changes but is quickly overcome by density’s dominant contribution to changes in volume for both peaks. This indicates the importance changes in material density in predicting the volume yield of preceramic polymers. |