PBI examples of tensile strength retention versus temperature C

For long-term heat ageing, property retention depends on the property considered. Impact strength and elongation at break are especially heat-sensitive characteristics. 

After 500 h exposure in hot air, retentions based on compressive strength are  

The behaviour at low temperatures is good, depending on the mechanical constraints undergone. Mechanical properties vary little between room temperature and -70°C. Suitably designed parts are usable at cryogenic temperatures, -160°C for example. Notched Izod impact strengths are weak and parts must be designed to avoid stress concentrators. 

These results relate to some grades only and cannot be generalized. 

The mechanical properties are good but notched Izod impact strengths are weak and parts must be conveniently designed to avoid stress concentrators. 

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Figure 4.129. PBI examples of tensile strength retention (%) versus temperature (°C)...

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