Synthesis and Characterization of Meltable and Soluble Reticulating Polysilazane Modified via Melamine Toward SiCN Ternary Ceramics.

The molecular structure of polymer has a great influence on the physical and chemical properties of polysilazane and the properties of ceramics pyrolyzed from the polysilazane. The polysilazane with reticulating molecular structure has good performance generally. The performance of the precursor can be effectively improved by reasonable molecular structure design and control of the synthesis process. In this paper, a reticulating polysilazane PSZ-M with outstanding meltability and solubility were synthesized via an aminolysis reaction between dichloromethylsilane (DCMS) and hexamethyldisilazane (HMDZ), and using the melamine as additive. The properties and the ceramization process of PSZ-M, as well as the molecular structure and properties of derived SiCN ceramic, were well studied. The melamine can be introduced via the dehydrogenation reaction between N–H and Si–H. The ceramics yield was enhanced to 63.18% at 900 °C after the introduction of melamine. The SiCN ceramics derived from the PSZ-M can remain amorphous when pyrolyzed below 1400 °C, the crystal phase of SiC, SiN4 were detected for 1500 °C treated samples. The using of melamine as an additive to synthesis polysilazanes has led to the development of a convenient approach for constructing polysilazanes with reticulating structure and ideal performance, which supports a strategy for the structure design of preceramic polymers. [ABSTRACT FROM AUTHOR]