Polyetheretherketone is a rigid thermoplastic with a high service temperature. Because of this high temperature, PEEK can be autoclaved many times. It is extremely resistant to chemical attack and thermal degradation. It can be used for implants, as well as applications with a high vacuum.
These materials have a wide range of interesting properties, but are more expensive as a result.
Related to PEEK, polyether imide is a rigid thermoplastic with a high service temperature. PEI has even more high temperature resistance than PEEK, but suffers in impact strength. Ultem® is the trade name for medical-grade PEI.
Polycarbonate is known for being optically clear and tough. Its best-known application is in bulletproof glass. In the medical industry, it is typically used in rigid packaging that must also be clear.