Polyether Sulfone (PES or PESU) is a high-temperature aromatic sulfone polymer that exhibits xceptional thermal, mechanical, and chemical resistance properties. PES is part of the PAES (Poly Aryl Ether Sulfone) family of polymers, which includes PSU, PES, and PPSU. ThermaX PES is an amorphous polymer and has excellent dimensional stability and creep resistance.