PEEK

PEEK = Polyether ether ketone
chemical element
physical

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

1320 kg/m³
3.6 GPa
90-100MPa
50%
55 kJ/m²
343 °C
0.25 W/(m·K)
0.1%
chemical Polymers are obtained by step-growth polymerization by the dialkylation of bisphenolate salts.
properties PEEK 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.
Manufacturing may be simple and with low cost with 3D-printing.
applications

 

PEEK 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 dental implants ¹. PEEK is tried to use in place of titanium. It is also used as coating for metal implants. 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. 
special There are trials to coat PEEK with titanium.