Silicone resins are not perfect. Despite their excellent hydrophobicity and low water absorption, they are relatively resistant to water vapor, especially high-pressure vapor. In addition, silicone resins have limitations when it comes to solvent resistance.
The performance of silicone resins is also affected by a variety of factors. Among them, the ratio of organic groups to silicon (R/Si) in the molecular composition plays a key role. Generally speaking, silicone resins with practical value have an R/Si ratio between 1.2 - 1.6. When the value of R/Si is small, the resulting silicone resin can be cured at lower temperatures; on the contrary, when the value of R/Si is large, the curing of the silicone resin requires prolonged baking at high temperatures of 200-250°C. In addition, the phenyl groups in the organic groups are not as important as the phenyl groups in the silicone resin, but are more important than the phenyl groups. In addition, the phenyl content of the organic groups also has an important effect on the properties of silicone resins. The lower the phenyl content, the softer the film and the faster the shrinkage; the higher the phenyl content, the harder the film and the more thermoplastic it is. When the phenyl content is between 20% - 60%, the film's bending resistance and heat resistance tend to reach the best state.

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