Polyether Ether Ketone (PEEK) Encapsulated NdFeB Stir Bars and Discs
Neodymium Iron Boron (NdFeB) is the strongest of the permanent magnetic materials. Previously, Neodymium Iron Boron has not been available as a completely encapsulated Magnetic Stir Element. V&P is the only source of Polyether ether ketone (PEEK) encapsulated NdFeB. We offer a high and a low-temperature resistant form of the NdFeB which can be selected to fit your application. We also offer Samarium Cobalt (SmCo) rare earth magnets which are available for even higher-temperature applications. By way of comparison, Alnico magnets the most commonly used in magnetic stir bars, are much weaker at only 7 MGO. So if you need to stir viscous material, soil samples, wood chips, or particulates at high speeds or grind nanoparticles with glass beads, this is the system for you.
Polyether ether ketone (PEEK) is a thermoplastic with excellent mechanical and chemical resistance properties that are retained through higher temperature applications. Because of these inherent properties, PEEK is an ideal material for use as a magnetic stir bar in high mechanical stress-induced applications for its abrasion resistance or when chemical attacks are a concern. See detailed information on the properties of PEEK.
PEEK is much superior to PVDF in grinding applications or applications where glass beads or Zirconium Oxide beads are used to make nano particles.
V&P is the first to offer this option with our new PEEK POWER Magnetic Stir Bars. Made with PEEK-CLASSIX from Invibio. See detailed information on PEEK-CLASSIX.
PEEK Properties
The thermal oxidative stability of PEEK is excellent and the material has a UL-rated continuous operating temperature of around 250°C (depending on the grade used). PEEK has excellent resistance to burning and very low flame spread being rated as UL 94 V-0 for thicknesses down to 2 mm. The LOI (Limiting Oxygen Index) is 35% (depending on grade) and even when burning the material has one of the lowest smoke generation characteristics of engineering thermoplastics.
Chemical Resistance
PEEK has outstanding chemical resistance and is extremely resistant to most organic and inorganic chemicals. It is dissolved or decomposed only by concentrated anhydrous or strong oxidizing agents. The material has exceptionally good resistance to hydrolysis in hot water and remains unaffected after several thousand hours at more than 250°C in pressurized water. PEEK is not greatly resistant to UV radiation but has good resistance to beta and X-rays, as well as exceptional resistance to gamma rays (more than 1000 Mrad without significant loss in mechanical properties). These properties allow for ease of sterilization, and coupled with good biocompatibility (USP Class VI), PEEK makes a strong candidate for medical applications.
Physical and Mechanical
PEEK has greater strength and rigidity than many of the other engineering thermoplastics, making it tough over a wide range of temperatures. It has good mechanical properties, including impact resistance, low wear rate, and a low coefficient of friction, but more importantly, these properties are also retained over a wide temperature range.
PEEK-CLASSIX Certifications:
- US Pharmacopoeia Class VI
- ISO 10993-1 Guidance
- ISO 10993-5 Cytotoxicity
- ISO 10993-10 Sensitization
Applications
- Nano suspension synthesis in drugs where the PEEK stirrer can be used to break down drug compounds in combination with zirconium oxide beads. Other materials, such as PVDF encapsulated magnets or even stainless steel will be quickly damaged by the zirconium oxide beads, leading to sample contamination, while PEEK will remain virtually undamaged for a prolonged (8 hours) period of mixing.
- Grinding wood pulp using the PEEK stirrers for fermenting biomass. One of our customers requested some of our PVDF Magnetic Stir Bars but quickly found out that the PVDF because it is a soft material, was destroyed by the wood pulp. We recommended using one of our PEEK Stir Bars and the problem was solved.
