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Published on: February 7, 2017
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Carborane-Containing Aromatic Polyimide Films with Ultrahigh Thermo-Oxidative Stability
Fulin Liu1,2, Guangqiang Fang3, Haixia Yang1
1Laboratory of Advanced Polymer Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Polymers
|November 28, 2019
Summary
New carborane-containing aromatic polyimide (CPI) films exhibit exceptional thermal stability up to 700 °C. These advanced polymer films form protective boron oxide layers, acting as a self-healing shield against degradation.
Area of Science:
- Materials Science
- Polymer Chemistry
Background:
- Aromatic polyimides (CPI) are known for their thermal stability.
- Achieving ultrahigh thermo-oxidative stability at elevated temperatures remains a challenge.
Purpose of the Study:
- To develop carborane-containing aromatic polyimide (CPI) films with enhanced thermo-oxidative stability.
- To investigate the protective mechanism of carborane groups at high temperatures.
Main Methods:
- Copolymerization of aromatic dianhydride and carborane-containing aromatic diamine to form poly(amic acid) (PAA) resin.
- Casting PAA solution and subsequent thermal imidization to create CPI films.
- Thermo-oxidative aging tests at 700 °C to evaluate stability.
Main Results:
- CPI films demonstrated ultrahigh thermo-oxidative stability at 700 °C.
- Carborane groups converted to boron oxides, forming protective multilayered surface layers.
- The boron oxide layer acted as a self-healing shield, enhancing degradation activation energy and preventing oxygen contact.
- CPI-50 film retained flexibility and 50% mechanical strength after aging at 700 °C for 5 minutes.
Conclusions:
- Carborane incorporation significantly enhances the thermo-oxidative stability of aromatic polyimides.
- The self-healing boron oxide layer is key to the material's performance at extreme temperatures.
- These CPI films show promise for high-temperature applications.
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