Polycarbonates

Abstract

Polycarbonates are an unusual and extremely useful class of polymers. The vast majority of polycarbonates are based on bisphenol A (BPA) and sold under the trade names Lexan, Makrolon, Calibre, and Panlite. BPA polycarbonates having high glass‐transition temperatures are widely regarded for optical clarity and exceptional impact resistance and ductility at room temperature and below. Other properties such as modulus, dielectric strength, or tensile strength are comparable to other amorphous thermoplastics at similar temperatures below their respective glass‐transition temperatures. Polycarbonates are prepared commercially by two processes: Schotten–Baumann reaction of phosgene and an aromatic diol in an amine‐catalyzed interfacial condensation reaction, or via base‐catalyzed transesterification of a bisphenol with a monomeric carbonate such as diphenyl carbonate. Important products are also based on polycarbonates in blends with other polymers, copolymers, branched resins, flame‐retardant compositions, foams, and other materials. Polycarbonate, produced globally, has been the object of research studies, owing to its widespread utility and unusual properties. This article summarizes the preparation, properties, and utility of polycarbonates.