Synthesis and Characterization of a Novel Preceramic Polymer for SiBNC Ceramic Fibers

A new approach for the synthesis of polymer precursor for quaternary SiBNC fibers is presented. The inexpensive, commercially available reactants n-propylamine (C3H7NH2), trichlorosilane (SiHCl3) and boron trichloride (BCl3) were used in a simple one-step reaction. The reaction mainly involved the co-polymerization between Si-Cl, B-Cl and N-CH2CH2CH3 with C3H7NH2 evaporation. Characterization of synthesized polymer was performed by FT-IR and NMR. The polymer has a relatively linear-chain chemical structure, and could be easily converted into flexible green fibers by melt-spun with diameter of 24 μm. After pyrolysis process at 1000 °C under nitrogen atmosphere, SiBNC ceramic fibers were obtained with a diameter of about 19 μm. Those fibers showed average tensile strength of 1.05 GPa and it remained in the amorphous state up to 1600 °C, which made them as the promising candidates for reinforcements in ceramic matrix composites for hightemperature application.