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.

In this study, blends of the bio‐based poly(limonene carbonate) (PLimC) with different commodity polymers are investigated in order to explore the potential of PLimC toward generating more sustainable polymer materials by reducing the amount of petro‐ or food‐based polymers. PLimC is employed as minority component in the blends. Next to the morphology and thermal properties of the blends the impact of PLimC on the mechanical properties of the matrix polymers is studied. The interplay of incompatibility and zero‐shear melt viscosity contrast determines the blend morphology, leading for all blends to a dispersed droplet morphology for PLimC. Blends with polymers of similar structure to PLimC (i.e., aliphatic/aromatic polyester) show the best performance with respect to mechanical properties, whereas blends with polystyrene or poly(methyl methacrylate) are too brittle and polyamide 12 blends show very low elongations at break. In blends with Ecoflex (poly(butylene adipate‐co‐terephthalate)) and Arnitel EM400 (copoly(ether ester)) with poly(butylene terephthalate) hard and polytetrahydrofuran soft segments) a threefold increase in E‐modulus can be achieved, while keeping the elongation at break at reasonable high values of ≈200%, making these blends highly interesting for applications.