Polyetherketones
Polyetherketones (PEK for short) are polymers whose molecular backbone contain alternating ketone (R-CO-R) and Ether (R-O-R) functionalities. The most common are Polyaryletherketones (PAEK), in which there is an aryl group linked in the (1–4)-position between each of the functional groups. The backbone, which is thus very rigid, gives the materials very high glass transition and melting temperatures compared to other plastics.