Curing preceramic SiBNC polymers infusible by radical polymerization

Borosilazane polymers carrying vinyl groups were examined as precursors for shaping and curing polymeric green bodies. The unsaturated C-C bonds present have allowed to cure these blends infusible using the radical starter dicumyl peroxide within 75 min at 130 degrees C, and within 5-15 min at 160 degrees C. A fully vinyl-functionalized single source precursor is compared with copolymers made from established borosilazanes with vinylsilazanes. The resulting ceramics are at least stable up to 1556 degrees C against crystallization, an initial mass loss of 2.5% is observed at temperatures of 1800 degrees C for some systems. Surprisingly, the ceramics with the highest temperature stability and crystallization resistance were not achieved via the homogeneous single source precursor, but from a copolymer of aminolysed trichlorosilylamino-dichloroborane (TADB) with vinyl-methyl-silazane.