Polysiloxane polymers generally have low molecular weight and poor thermal stability. The polysilazane polymer with a certain proportion of methyl group will show good ductility and thermal stability, which can effectively improve the heat resistance of polysilazane.

The research of polysilazane is mainly focused on ceramic precursor and ceramic fiber, but there are few reports on improving the heat resistance of polysilazane. Through the ring opening polymerization of octamethylcyclotetrasilazane and the introduction of methyl group, the molecular structure of polysilazane with good heat resistance is designed, which provides certain design ideas and theoretical basis for the later structure of polysilazane with specific performance. The specific research ideas are as follows: octamethylcyclotetrasilazane as the ring opening monomer, hexamethyldisilazane as the end capping agent, toluene as the end capping agent As the reaction solvent, under the protection of dry nitrogen, ruthenium based catalyst was used as the initiator for catalytic ring opening polymerization.