J. Clade (Sp), R. Herborn, R. Krüger, Fraunhofer-Institut für Silicatforschung, Würzburg (Germany)
The material system Si-B-N-C is a most promising candidate for high-temperature applications. In this system, a new group of molecular precursor compounds, sharing the structural feature C-Si-N(H)-B, has been synthesized in the course of the last years. The aminolysis and polycondensation of one of these compounds, MADB (methyl-dichlorosilylamino-dichloroborane), leads to polymers which are solid at room temperature, but meltable at elevated temperatures. The rheological properties of these polymers with respect to their capability of being transformed into green fibers were intensively investigated and optimized. A manufacturing process for ceramic fibers, consisting of polymer synthesis, fiber spinning, curing, and pyrolysis, could thus be developed.
The interrelationships between structural features of the polymers, their capability of being transformed into ceramic fibers, and the properties of these fibers are discussed.
