Atmosphere‐Controlled Thermolysis of Decarborane–Diphenylamine Copolymer for Electrospun Ultrafine Boron Carbon Nitride Fibers

Polymer‐derived methods are one of the most important tools for functional ceramics with atomic homogeneous dispersed. In this article, soluble boron carbon nitride (BCN) preceramic polymer was synthesized via direct copolymerization of decarborane and diphenylamine, which suggest a high ceramic yield of about 78 wt%, as well as a linear structure with average molecular weight of 2366 and PDI of 1.11. After thermolysis process in nitrogen atmosphere and further annealing at above 1300°C, amorphous BCN ceramic with separated BN and B 13 C 2 crystalline was obtained. By switching the nitrogen atmosphere to ammonia during the pyrolysis process, BCN ceramic with lower carbon content and higher nitrogen content was obtained. The ultrafine fibers with average diameter of 1.5 μm were prepared by electrospinning of the copolymer solution in THF. The ultafine BCN nanofibers were produced with carbon contents of 41.4 and 0.4 wt% via pyrolysis under nitrogen and ammonia atmosphere, respectively.