The tensile strength, flexural strength, flexural modulus, impact strength and elongation of PEEK are very high at room temperature. These values are higher than those of ordinary plastics, but there is a large drop when the temperature exceeds the glass transition temperature. After reinforced with glass fiber and carbon fiber, the tensile strength, impact strength, flexural strength and modulus increase greatly, and the elongation decreases greatly. In addition, PEEK also has excellent creep resistance, and the fatigue resistance of the unnotched specimen is also outstanding, and it can withstand the repeated effects of the load.
PEEK has excellent heat resistance, and its Tg is 143 ° C, Tm is 334 ° C, the heat distortion temperature is 135 ~ 160 ° C when not enhanced, and the high continuous use temperature can reach 240 ° C. After reinforced with 20% glass fiber, the heat distortion temperature reached 286 ° C, and the heat distortion temperature after reinforced with 30% glass fiber or carbon fiber exceeded 300 ° C.
In addition, PEEK also has high thermal oxygen stability. The thermogravimetric curve shows that the thermal weight loss at 400 °C is 0, 2.5% at 500 °C, and 59% at 600 °C. PEEK has excellent electrical properties and very large volume resistivity. The dielectric constant is 3.2-3.3 at a frequency (50-1010 Hz) and temperature (0-150 °C), and the dielectric strength is 16-21 kv/mm. It is not affected by humidity and can be used as a Class C insulation material. PEEK is resistant to all chemical media except concentrated sulfuric acid, and maintains high chemical stability even at high temperatures. Its water resistance is very prominent, it can be used for a long time in 200 ° C water vapor, and it can be used for a short time in 300 ° C high pressure water vapor. Since the macromolecular chain of PEEK contains a large amount of benzene ring, it can absorb a large amount of rays without being damaged, and the radiation resistance is also outstanding.
