 The term "polysulfone" is normally used for polyarylethersulfones (PAES), since only aromatic polysulfones are used commercially.Furthermore, since ether groups are always present in these polysulfones, PAESs are also referred to as polyether sulfones (PES), poly(arylene sulfone)s or simply polysulfone (PSU).The simplest polysulfone poly(phenylene sulfone), known as early as 1960, is produced in a Friedel-Crafts reaction from benzenesulfonyl chloride