Polyether ether ketone (PEEK) and polyetherimide (PEI) for fused filament fabrication (FFF) in medical applications

Recently, high-performance polymers (HPP) have been exploited in the world of additive manufacturing (AM) as a result of improved techniques and the ability to process these materials which require higher processing temperatures. These materials present enhanced mechanical properties, chemical resistance, and thermal stability, increasing AM potentials beyond prototyping applications. Polyether ether ketone (PEEK) has been recognised for its mechanical properties due to its semi crystalline nature and established itself as a biomaterial, possessing biocompatibility and chemical resistance. Polyetherimide (PEI) is renowned for its thermal stability and has been utilised in high temperature-dependent applications. PEEK and PEI are one of the few miscible blends of HPPs, characterized through the presence of a single glass transition temperature. Both materials individually present properties which make them ideal for biomedical applications and through the blending of these materials the biomedical industry could benefit from the synergistic outcome. This review paper will look at PEEK, PEI, and their blends, focusing on the printing parameters, crystallinity and reinforcements. It will also take a look at some of the areas which PEEK and PEI are currently being used, including, implants, prosthetics, and Tissue Engineering.