Normally, when we think about polycarbonate, we think about the homopolymer based upon bisphenol A. However, there are many different variations on polycarbonate, including copolymers. Recently, I was working on a project and the part was injection molded from a poly(ester) carbonate copolymer. The copolymer is produced through the incorporation of isophthalate and terephthalate functionality into the polymer chain. This results in thermal, mechanical, chemical, and physical differences between polycarbonate homopolymer and poly(ester)carbonate copolymer. The structural variation means that the copolymer will have improved thermal stability, enhanced creep resistance, and better chemical resistance.
However, the tradeoff is reduced ductility and lower stiffness within the poly(ester)carbonate copolymer. Additionally, the copolymer requires a higher processing melt temperature for injection molding.
Once again – polymer structure determines performance properties.
