The topic of the presented project is the development of polymer precursors for composites with a pyrolyzed matrix reinforced with ceramic fibers. Resins based on siloxanes with different carbon to silicon ratios will be studied as a precursor. Oxide-free carbosilanes, silazanes, boron-containing siloxanes and their copolymers will also be studied. The main goal of their research is to find the optimal precursor with suitable technological parameters in the polymer state. In the pyrolyzed state, these materials must exhibit thermal and structural stability and oxidation resistance. The composite prepared from such precursors and Nextel 720 ceramic fibers will be pyrolyzed to a temperature of up to approx. 1000 ° C.