Ring-opening copolymerization of lactide/lactide derivatives and trans-limonene oxide is used for the synthesis of sustainable block copolymers. The method alters the properties of bio-based, non-food-based poly(limonene carbonate).

Poly­(limonene carbonate) (PLimC) has a huge potential as a sustainable biobased polymer due to its promising property profile and the availability of the raw materials from nonedible resources, i.e., limonene from orange peel. PLimC and related terpene-based polycarbonates have not been processed from the melt state successfully due to their comparably low decomposition temperatures. Indeed, melt-processed PLimC samples are brittle and colorized. To change the paradigm, we have investigated compounds of PLimC with biobased ethyl oleate (EtOL). The glass transition temperature (T g) and melt viscosity of these compounds can be readily controlled by the EtOL content. The melt-processed PLimC/EtOL compounds showed improved mechanical properties without significant loss in optical properties as compared to neat PLimC. Interestingly, the PLimC/EtOL compounds could be melt-processed a second time without significant loss of mechanical and optical properties, which could mark an important step toward recyclability.

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