Polysilazanes are a class of inorganic polymers with Si-N bonds as repeating units in the main chain. Researchers have been studying polysilazanes for nearly a century, since A. Stock et al. first reported the preparation of polysilazanes from chlorosilanes using ammonia in 1921. Compared with its similar polymers - polysiloxanes with Si-O chains as repeating units in the main chain - polysilazanes are much less well developed and applied. There are two main reasons: first, most of the polysilazanes are relatively active, with water, polar compounds, oxygen and other high reactivity, so it is more difficult to save and transport; second, the preparation method of polysilazanes is not yet perfect, and can not effectively control the reaction products, the reaction products are complex, the molar mass is low. Nevertheless, after nearly a century of development, commercialized polysilazanes have been developed, such as the all-hydrogen polysilazanes of Clariant (Switzerland), Teon (Japan), and AZ Electronic materials (UK), and the polyurethane-silazanes of KiON (USA) under the brand name of “ceraset”, Polysilazanes; in addition, Dow Corning Company of the United States and Bayer of Germany also have some polysilazane products; in China, the Institute of Chemistry of the Chinese Academy of Sciences has developed the PSN series of polysilazanes. The successful commercialization of polysilazanes has promoted its application research in various aspects, among which the research as ceramic precursor is the most abundant.

The development of polysilazanes
1.First of all, in the 1920s, researchers began to try to synthesize and classify silazane rings and oligomers, in which A. Stock made a pioneering work, but the development of polysilazanes was slow during this period.
2. The outbreak of World War II prompted the successful commercialization of polysiloxanes in the 50s and 60s, which greatly aroused the researchers' enthusiasm for the study of polysiloxane-like polymers - polysilazanes. During this period, the researchers mainly adopted the similar method of preparing polysiloxanes, such as ring-opening polymerization to prepare polysilazanes, and studied their main properties in the hope of being able to be applied in the form of polymers, but the progress was extremely limited. the progress made was extremely limited.
3. In 1976, S. Yajima et al. succeeded in obtaining SiC fibers by cracking polysilanes, and SiC fibers under the trade name Nicalon were applied. The researchers turned their attention to polysilazanes, expecting to prepare Si3N4 and Si-C-N fibers by designing polysilazanes with suitable molecular structures. Therefore, during this time, researchers focused on the spinnability of polysilazanes and how to cure the cleavage. Since then, polysilazanes as ceramic precursor polymers have become a hot research topic for researchers, and the polymer precursor method has also become a new ceramic preparation method. In short, it is a method of preparing ceramic products by cracking polymers with specific molecular compositions at high temperatures (generally above 1,000 ℃) under a certain atmosphere.
4. In the 1990s, R. Reidel's research group introduced the B element into polysilazanes to produce Si-B-C-N ceramics with a temperature resistance of 2,200 ℃, which motivated researchers to focus on modifying polysilazanes in order to prepare functional or Si-C-N ceramics with higher temperature resistance. Subsequently, Si-Fe-C-N ceramics with magnetic properties, Si-Ag-C-N ceramics with antimicrobial properties, and Si-Zr-C-N ceramics with good anti-crystallization properties have been prepared by modifying polysilazanes.
Polysilazanes have been mainly used as precursors for Si3N4 or Si-C-N ceramics, so most of the work focuses on the use of its high-temperature pyrolytic conversion to form ceramic materials to expand their applications, which have been expanded to coatings, adhesives, ceramic matrix composites, ceramic films, microelectromechanical systems (MEMS) and porous ceramics and other fields.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150A. 
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.