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The growing burden of plastics on the environment represents an urgent global challenge. We report a robust strategy to convert waste cooking oil (WCO), an abundant biomass waste, into chemically recyclable polyesters that mimic polyethylene in performance but offer degradability and excellent adhesion. Through catalytical transformation, both the fatty acid and glycerol components of WCO are valorized into monomers, which are then polymerized into long-chain linear and branched aliphatic polyesters with tunable crystallinity and mechanical properties. These materials, especially branched polyesters with long aliphatic side chains, rival low-density polyethylene (LDPE) in flexibility and strength and notably outperform commercial adhesives in shear strength by creating robust yet temporary bonds with multiple substrates, offering safety, ease of handling, and removability. These mimics can be depolymerized and repolymerized under mild conditions, even in mixed plastic streams. Simulations and experiments reveal that the strikingly increased crystallinity in polyesters with longer side chains is driven by side-chain alignment, offering new molecular insights for materials design. This work illustrates a powerful waste-to-materials approach that aligns with circular economy principles and elevates the potential of biomass in sustainable plastics’ innovation. 

Most current strategies for carbon management require CO2 removal (CDR) from the atmosphere on the multi-hundred gigatonne (Gt) scale by 2100. Mg-rich silicate minerals can remove >105 Gt CO2 and sequester it as stable and innocuous carbonate minerals or dissolved bicarbonate ions. However, the reaction rates of these minerals under ambient conditions are far too slow for practical use. Here we show that CaCO3 and CaSO4 react quantitatively with diverse Mg-rich silicates (for example, olivine, serpentine and augite) under thermochemical conditions to form Ca2SiO4 and MgO. On exposure to ambient air under wet conditions, Ca2SiO4 is converted to CaCO3 and silicic acid, and MgO is partially converted into a Mg carbonate within weeks, whereas the input Mg silicate shows no reactivity over 6 months. Alternatively, Ca2SiO4 and MgO can be completely carbonated to CaCO3 and Mg(HCO3)2 under 1 atm CO2 at ambient temperature within hours. Using CaCO3 as the Ca source, this chemistry enables a CDR process in which the output Ca2SiO4/MgO material is used to remove CO2 from air or soil and the CO2 process emissions are sequestered. Analysis of the energy requirements indicates that this process could require less than 1 MWh per tonne CO2 removed, approximately half the energy of CO2 capture with leading direct air capture technologies. The chemistry described here could unlock Mg-rich silicates as a vast resource for safe and permanent CDR. 

Poly(lactic acid) (PLA) offers a renewable and degradable alternative to petroleum-based plastic, but its mechanical properties are not ideal for many applications. Herein, we describe the synthesis and polymerization of oxo-3,8-dioxabicyclo[3.2.1]octane (ODO), a bio-derived bicyclic lactone, and show that copolymers of L-lactide (LA) with small amounts of ODO have improved mechanical properties over PLA. Homopolymerization of ODO to poly(oxo-3,8-dioxabicyclo[3.2.1]octane) (PODO) is optimized for both solution-phase, organocatalytic and melt-phase, metal-catalyzed conditions. In comparison to the monocyclic analog, ε-caprolactone (CL), ODO has a lower enthalpy of polymerization and faster rate of polymerization. PODO is an amorphous, elastomeric polyester that has a 90 °C higher Tg than poly(ε-caprolactone) (PCL). Statistical copolymerization of LA with small fractions of ODO yields tough and transparent thermoplastics that have over 12× elongation at break compared to native PLA, while maintaining Tg, Young’s modulus (E), and yield strength. Together, these results describe how the incorporation of the tetrahydrofuran ring alters polymerizability and the thermomechanical properties of the homopolymer and copolymer materials.