In the important precursor polymer of polysilazane, the content of vinyl groups acts like a precise "molecular switch", precisely regulating the core properties of the material ranging from processing performance to final application. Its crucial role runs through the entire process of material synthesis. 
The core function of vinyl is primarily manifested in its outstanding reactivity. Under heat or catalyst conditions, vinyl can undergo crosslinking through two main pathways: one is through an efficient silane-hydrogen addition reaction with Si-H bonds on the molecular chain; the other is self-polymerization among vinyl groups. These reactions are like "molecular stitches", connecting the linear polysilazane macromolecules into a robust three-dimensional network structure. The higher the vinyl content, the more potential "sewing points" there are, allowing the material to form a denser and more stable crosslinked structure, thereby significantly improving the ceramic yield and endowing the final product with excellent high-temperature resistance and mechanical strength. 
Therefore, by precisely controlling the content of vinyl groups, materials scientists can "customize the performance" of polysilazanes. A high vinyl content is suitable for preparing dense ceramic coatings or bulk materials with high hardness and strength; while a lower content helps maintain the flexibility of the material, which is suitable for preparing porous ceramics or for applications requiring certain deformation capabilities.