This review states recent developments in the preparation of ceramic fibers using a chemical procedure denoted as Pyrolysis of Preceramic Polymers. Synthesis strategies which are used to prepare Polymer‐Derived Ceramics (PDCs) fibers from molecular and polymeric precursors are presented by refering to the crystalline boron nitride (BN) fibers and amorphous silicoboron carbonitride (SiBCN) fibers as models. The influence of the structure of the molecular and polymeric precursors, in which specific functional groups and structural motifs are incorporated on the melt‐spinnability, polymer‐to‐ceramic conversion and fiber properties is discussed. A minimum cross‐linking degree combined with the presence of flexible structural patterns and plasticizing functional groups yield controlled melt‐viscoelastic properties and appropriate thermal stability at low temperature to produce high quality fine‐diameter endless green fibers in a stable melt‐spinning process. These structural motifs and functional groups are also capable to undergo cross‐linking reactions and provide fiber curability allowing the polymer backbone to be interlocked, the fiber integrity to be thereby maintained. As‐cured fibers are then pyrolyzed in a controlled atmosphere with retention of the shape to produce the ceramic fibers in the desired composition and structure.
†Member of IUF (Institut Universitaire de France)
Acknowledgment
The authors thank EADS ST for supporting works on BN fibers and the Deutsche Forschungsgemeinschaft (DFG) for supporting the work dedictated to SiBCN fibers. The European Community is acknowledged for support through the Marie Curie Research Training Network “PolyCerNet” (Contract MRTN‐CT‐2005‐019601). We also gratefully acknowledge discussions with Dr. Markus Weinmann, Prof. Fritz Aldinger, Prof. Corneliu Balan, Dr. Chrystel Gervais and Dr. Florence Babonneau.
Notes
†Member of IUF (Institut Universitaire de France)