Biodegradable Materials from Renewable Resources: Catalysts for Sustainable Synthesis of New Polyesters

Plastics are an essential part of everyday life, however, an ever-growing excess of plastic waste is becoming a persistent plague. Furthermore, most plastics are derived from petroleum feedstocks and are draining valuable energy resources. Traditional plastics are made of olefin based polymers, but a change in the environmental impact of plastics can be effected by changing the compositions of the polymers that we invest in plastic materials. Polyesters are polymers that introduce oxygen atoms into their backbone chain, making them better mimics of naturally occurring polymers and thus easier to degrade. Additionally, many of the starting materials for the creation of polyesters are considered biorenewable. Current synthetic methods available for making polyesters consist of harsh, energy intensive condensation copolymerizations or ring-opening polymerizations with narrow monomer scope. These methods limit the available properties and functionalities accessible to polyesters as a class and thus hinder the range of their applications. We present two catalytic chain-growth approaches able to alternatively copolymerize a variety of epoxides with cyclic anhydrides. These methods allow use of bio-renewable monomer feedstocks and mild conditions in an effort to develop a sustainable alternative for polyester synthesis.