Polyether ether ketone is a semi-crystalline aromatic thermoplastic whose repeat unit joins para-substituted phenyl rings through ether and ketone linkages ^[1]. The aromatic backbone gives chemical resistance and a high continuous service temperature, while the crystallinity of about thirty per cent fixes stiffness and the amorphous phase governs toughness ^[1]. The polymer melts near 343 degrees Celsius, keeps a glass transition at about 143 degrees, dissolves only in strong acids, and is sulfonated by concentrated sulfuric acid at the ring ^[1]. Carbon or glass fibre raises modulus and creep resistance and reduces the mismatch in thermal expansion with metal ^[2]. Because the elastic modulus approaches that of cortical bone, the unfilled polymer is examined as an implant material, although its bioinert surface bonds weakly to tissue ^[3].