ABSTRACT
Polyaryl ether ketones, or PAEKs, are highly aromatic, mostly semicrystalline thermoplastics. The letters E and K refer to the sequence of ether and ketone units in their structures. Examples of this new class of high-performance thermoplastics are PEEEK, PEEK, PEEKEK, PEK, PEEKK, PEKEKK, PEKK, and PEKKK, with their chemical repeat units shown in Figure 15.1. Because of their relatively stiff aromatic polymer backbones, PAEKs exhibit some of the highest thermal transitions found in commercially available polymers today. As a result, these polymers can be continuously used at temperatures as high as 240°C in the case of polyether ether ketone (PEEK) [1]. They possess a good combination of properties, including toughness and high mechanical strength over a broad temperature range, thermal stability, solvent and chemical resistance, very low smoke emission in flammability tests, and good electrical properties. They have been shown to resist basic as well as moderately acidic environments.
