PEKK

PEKK = PolyEther Keton Ketone
chemical element
physical

Density
Young´s modulus (E)
Tensile Strength (σt)
Elongation @ break
melting point
water absorption, 24 hrs

1.3 g/cm³
5.5 GPa
138 MPa
> 30%
360 °C
< 0.2%
chemical Polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts.
properties PEKK is highly resistant to thermal degradation, as well as to attack by both organic and aqueous environments. It is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. Its alternating stress of excellent fatigue resistance is the most outstanding in all plastic,  comparable with alloys.
applications

 

PEKK is used to fabricate items used in demanding applications, including bearings, piston parts, pumps, HPLC columns, compressor plate valves, and electrical cable insulation, ultra-high vacuum applications. It is used in aerospace, automotive and chemical process industries.
In medicine started usage in trauma, orthopedic, spinal, maxillofacial and in dental implants for abutments. There are no long-term experiences.
source: ID 35260610
biocompatibility Biocompatibility is proved in some publications ² and ³.
adverse effects n/a. It is discussed, if stress on bone may be inadequate for bone structuring. 
ISO 10993-1 (Oxford Performance Materials, Inc.)
ASTMF2820-12, Standard Specification for Polyetherketonketone (PEKK) polymers for Surgical Implant Applications