P Polyether Block Amide (PEBAX) Anja Car Department of Chemistry, University of Basel, Basel, Switzerland Polyether block amide is a multiblock copoly- mer with two types of segments, rigid polyamide (PA) and flexible polyether known under the trade name Pebax ® (http://www.pebax.com/ sites/pebax/en/home.page). It is obtained by polycondensation reaction (Fakirov 2005) of a carboxylic acid polyamide (PA6, P11, P12) with an alcohol-terminated polyether either polytetra- methylene glycol (PTMG) or polyethylene glycol (PEG) with general chemical structure (Fig. 1): Pebax ® consists of a linear chain of polyamide and polyether segment (block) in an orderly pat- tern and belongs to the group of thermoplastic elastomers (Holden et al. 1996). The combination of the rigid PA segment and the flexible polyether segment yields a block copolymer that exhibits a microphase-separated morphology (Bates 1991) due to the polarity differences between them: a crystalline PA and an amorphous polyether phase. The crystalline phase allows the copoly- mer to behave as a thermoplastic and the amor- phous phase imparts elastomer characteristics. The PA block melts in the range 130–200  C (Rulkens et al. 2012); the exact value depends on average molecular weight and content of the PA in the copolymer. Polyether block crystallizes at low temperatures, the value of which lies between 30  C and 20  C mostly depending on its molecular weight of the sequences (Bailey and Koleske 1976). The glass-transition temperature (Tg) is about 50  C due to the flexible segment (Patel and Spontak 2004). Through a proper combination of the polyamide and the polyether blocks, a wide range of Pebax ® grades with a variety of end-use characteristics can be designed (Pebax ® Technical Data Sheets). In general, these polymers possess a broad range of flexibility without the use of additives while maintaining high strength and toughness. Because of the thermoplastic qualities, it can be easily processed, extruded, and shaped at ele- vated temperatures, and upon cooling, its elastic- ity will allow it to return to its original length or shape after being stretched, compressed, or deformed. Depending on the nature and the rela- tive content of both segments, certain grades of Pebax ® copolymers have great film-forming abil- ity; thus, they attracted greater attention as a promising membrane material (Blume et al. 1990). The material offers strong resistance to a range of chemicals, and it is not affected by exposure to saline or sulfuric acid (Carson et al. 2010). It can be sterilized by a variety of methods including gamma radiation and steam autoclave. Pebax ® is considered as a high per- former among its thermoplastic elastomer peers because it is lightweight and because it offers a wider range of flexibility and hardness, a higher energy return, a greater resistance to fatigue, and # Springer-Verlag Berlin Heidelberg 2014 E. Drioli, L. Giorno (eds.), Encyclopedia of Membranes, DOI 10.1007/978-3-642-40872-4_736-2