Polyetheretherketone (PEEK), a high performance engineering thermoplastic offers superior chemical and water resistance and continuous temperature resistance of 250°C in hot water or steam without permanent loss in physical properties. The high oxidative and thermal stability of PEEK is a direct consequence of the molecular structure which allows electron overlap along the molecule.
Victrex, a leader in PEEK has recently developed PEEK-HT, w ith a glass transition temperature of 157°C (315°F) and a melting temperature of 374°C (705°F), it delivers extended high temperature performance, while offering all the key characteristics of natural Victrex PEEK, including toughness, strength and chemical resistance. PEEK HT offers 30°C higher continuous temperature than the standard grades. It maintains physical and mechanical properties at higher temperatures than standard grades, boasts up to three times the wear resistance of a standard PEEK polymer grade 450G at high temperatures, has a substantially higher tensile strength and flexural modulus at 250°C and possesses improved compressive strength versus standard PEEK polymer. Additional benefits include long-term creep and fatigue resistance over a wide temperature range. Like standard PEEK it has exceptional resistance to chemicals, solvents and fuels; inherent low flammability, low smoke emission; good electrical properties; excellent hydrolysis resistance; and consistent ease of processing. This is achieved by developing higher crystallinity in PEEK. Higher crystallinity results into higher mechanical properties along with higher continuous temperature resistance.
Key features of PEEK HT are :
- Superior high temperature performance
- Up to 3 times the wear resistance of standard VICTREX PEEK at high temperatures
- Excellent long-term creep and fatigue resistance over a wide temperature range
- Substantially higher tensile strength and flexural modulus at 250°C (482°F)
- Improved compressive strength
- Exceptional resistance to chemicals, solvents and fuels
- Inherent low flammability, low smoke emission
- Good electrical properties
- Outstanding hydrolysis resistance
- Consistent ease of processing
PEEK-HT polymer is market positioned as a premium material that is a cost-effective and lightweight alternative to metals. Key industries where there is a demand for extreme heat resistance applications include the automotive, aerospace and engineering industries. Typical applications encompass engine compartment parts, headlamp reflectors, aircraft components, sub sea connectors, heat exchanger elements and industrial valve linings. PEEK HT is available in powder or granules. Victrex anticipates producing even higher-temperature grades, as the market demands them. The company is also placing increased emphasis on development of specialty PEEK grades such as a silicone-modified PEEK, which provides toughness and impact performance approaching PC filled PEEK grades with 3-5 times the wear life of unfilled PEEK, and an ultra-high purity grade with 'order-of-magnitude' lower extractables. A version of PEEK-Optima with better mechanical properties has also been introduced.