High-Temperature Resistant Polyborosilazanes with Tailored Structures

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Boron-containing organosilicon polymers are vital preceramic materials for harsh environments.
• Current synthesis methods often involve harmful chemicals and complex routes, limiting their use.

Purpose of the Study:

• To develop a safer and simpler synthesis for boron-containing silicone polymers.
• To investigate the thermal stability and flame retardancy of the synthesized polymers.

Main Methods:

• A two-component, solventless synthesis route was employed.
• Cross-linked boron-containing silicone polymer (CPBCS) was synthesized by reacting multifunctional boron hybrid silazane monomers (BSZ12) and poly[imino(methylsilylene)].
• Polymer structure and boron content were tuned by adjusting monomer ratios.

Main Results:

• The synthesized CPBCSs demonstrated high thermal stability with 75 wt% char yield at 1000 °C.
• Excellent flame retardancy was observed, with low heat release capacity (37.9 J/g K) and total heat release (6.2 KJ/g).
• Good mechanical properties were noted, with reduced modulus of 0.30 GPa and hardness of 2.32 GPa.

Conclusions:

• The solventless synthesis offers a safer and more efficient alternative for producing boron-containing silicone polymers.
• The resulting polymers exhibit promising properties for applications in high-temperature and fire-hazardous conditions.
• These novel polysilazanes hold potential for advanced ceramics fabrication and protective materials.