Synthesis and self-assembly of biobased poly(limonene carbonate)-block-poly(cyclohexene carbonate) diblock copolymers prepared by sequential ring-opening copolymerization

Abstract

Polycarbonate diblock copolymers with a biobased poly(limonene carbonate) (PLimC) and a poly(cyclohexene carbonate) (PCHC) block were prepared via β-diiminate zinc catalysed living ring-opening copolymerization (ROCOP) of CO₂ and trans-limonene oxide and cyclohexene oxide, respectively. trans-Limonene oxide can be readily obtained from limonene, a renewable non-food source, that can be found in the peel of many citrus fruits and is the main component of orange oil. The block formation was realised by sequential addition of the epoxide monomers. The composition of the resulting amorphous poly(limonene carbonate)-block-poly(cyclohexene carbonate) (PLimC-b-PCHC) diblock copolymers was analysed by ¹H NMR spectroscopy. The self-assembly of the diblock copolymers into well-defined bulk morphologies was studied by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). Depending on the composition and molecular weight the formation of cylindrical, lamellar, and hexagonally perforated lamellar morphologies was observed.