Synthesis and Pyrolysis of Polysilazane Precursors Containing Linear-Cyclic Structures for Si/N/C-Based Ceramics

摘要

A new kind of polysilazane precursor containing linear-cyclic structure was synthesized from the de-lithium chloride condensation reaction of hexamethylcyclotrisi-lazane lithium salts (D_3~(NLi)) and 1,3-dichlorotetraorganodisilazanes [(CIR_1R_2Si)_2NH].Py-rolyses of these precursors and some comparable linear polysilazanes were carried out at 900 deg C in nitrogen.The results indicated that the existence of linear-cyclic structure in precursors provided relatively crosslinked or branched structures,which were helpfulf or improving ceramic yields.The precursor containing a linear-cyclic structure as well as reactive vinyl groups gave the highest pyrolytic yields.