In the chemical structure of polysilazanes, the electronegativity of silicon and nitrogen of the Si-N bond is 1.2, which is between the Si-C bond and the Si-O bond, and close to the Si-Cl bond, so the Si-N bond has about 30% ionic bond characteristics. At the same time, there is conjugation between the lone pair electrons on nitrogen and the 3d vacant orbitals on silicon (p-d cross-covering). The bond energy of Si -- N is about 360 kJ/mol, which is smaller than that of Si -- O and Si -- Cl, etc. Therefore, the Si -- N bond can easily be converted into other types of new bonds in the reaction, which is very beneficial for the development of new compounds. For example, it is easy to react with many electrophilic organic materials and nucleophilic organic materials, such as with epoxy resin or phenolic resin reaction, heat resistant nitrogen and heat and weather resistant Si elements into the compound, enhance the heat resistance and weather resistance of the compound, which is very useful for coatings.