Completely bio-based high molecular weight aliphatic poly(limonene carbonate) with excellent transparency, superior hardness compared to BPA-PC and a high Tg of 130 °C.

Completely bio-based poly(limonene carbonate) is a thermoplastic polymer, which can be synthesized by copolymerization of limonene oxide (derived from limonene, which is found in orange peel) and CO2. Poly(limonene carbonate) has one double bond per repeating unit that can be exploited for further chemical modifications. These chemical modifications allow the tuning of the properties of the aliphatic polycarbonate in nearly any direction. Here we show synthetic routes to demonstrate that poly(limonene carbonate) is the perfect green platform polymer, from which many functional materials can be derived. The relevant examples presented in this study are the transformation from an engineering thermoplastic into a rubber, addition of permanent antibacterial activity, hydrophilization and even pH-dependent water solubility of the polycarbonate. Finally, we show a synthetic route to yield the completely saturated counterpart that exhibits improved heat processability due to lower reactivity.

of biobased diols with phosgene derivatives [2,4] and the catalytic copolymerization of sustainable epoxides and CO 2 . [5,6] The copolymerization of biobased epoxides and CO 2 is of particular interest as it combines the use of biobased raw materials and the reduction of CO 2 . The anthropogenic emission of CO 2 accumulates to 32 Gt each year, which is caused mainly by the incineration of carbon matter. CO 2 is a greenhouse gas that contributes significantly to the warming of the earth's atmosphere. [7] Global warming increases chances of catastrophic weather phenomena and a rising sea level and, thus, impacts on our everyday life dramatically. Measures have been taken to reduce the emission and to contain the rise of CO 2 levels in the atmosphere in the last few decades. Part of these measures can be described by the concepts of carbon capture and storage/utilization (CCS/CCU). [8][9][10] The CCU deals with the separation and transformation of CO 2 from process gases (e.g., combustion gases in power plants and natural gas) to prevent emission of the greenhouse gas into the atmosphere. The separation step is achieved by the use of either chemical/physical absorbents or organic/inorganic membrane materials. [9,11] The class of absorbents is dominated nowadays by alkanol amine solutions, for example, monoethanolamine and diethanolamine, which require high temperatures for regeneration of the solvent. [12,13] Hence, these "wet-scrubbing" processes are connected to a considerable energy penalty that adds to the total emission of CO 2 . [14] The more energy-efficient-though less developed-technology relies on the use of membrane materials that separate CO 2 from other process gases by size exclusion (mostly hybrid metal-organic frameworks) [15,16] or solubility/diffusivity mechanisms (polymeric membranes), respectively. [17,18] The latter comprise a group of polymeric materials that exhibit permeabilities P (rate of transport through the matrix) and selectivities α (preference of one gas over the other; in this article the "ideal selectivity" is calculated as the ratio of two permeabilities) extending over several orders of magnitude. [19] However, those materials suffer frequently from low long-term stability, known as aging, which has prevented industrial application so far. [20] The large volumes of CO 2 captured in the industrial processes are either stored in gas-tight (often natural) basins (CCS) [10] or transformed into high-value chemicals via various chemical routes (CCU). Some of those routes are The biobased poly(limonene carbonate) (PLimC) synthesized by catalytic copolymerization of trans-limonene oxide and CO 2 unifies sustainability, carbon capture and utilization of CO 2 in one material. Films of PLimC show surprisingly high gas permeation and good selectivity. Additionally, it is not only very permeable to gases, but also to light, while simultaneously being a good heat insulator and mechanically strong, representing a novel type of material that is defined here as "breathing glass." Hence, this stud...

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