Unusual Stability of Amorphous Polymer Derived Ceramics at High Temperatures

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The objective of the proposed work is to discover what it is about the molecular structure of PDCs in the SiCN-SiCO system that renders them so resistant to crystallization and to creep. Recent SAXS studies have shown the presence of persistent nanodomains, 1-3 nm in size. However, the chemical and molecular constructions of these nanodomains are unknown. How they envolve from the organo-polymeric state into the ceramic state is not understood. Their thermodynamics of formation and interfacial energetics are unknown. Why these nanodomains preclude crystallization and creep is unclear. These questions must be answered in unison, and in relationship to each other. The US-German Team coalesces the expertise from NMR (D), SAXS (US), high temperature oxidative solution chemistry (US), ab-initio molecular modelling (D), inorganic synthesis and processing (D), and high temperature characterization (US), to solve this critical issue comprehensively and fundamentally. This international team is a natural coalition of, and also a recognition of the important role played be German scientists in the early developments of this field, and the recent role of the Americans in investigating the high temperature phenomenology of polymer-derived ceramics.