Chang Gao

Designing polymers that combine performance with sustainability remains a critical challenge. Here, we report high-performance elastomers derived from CO₂ and biobased monomers that integrate both mechanical toughness and closed-loop chemical recyclability through a single material feature: dynamic metal–ionomer cross-links. These ABA block polymers, synthesized from ε-decalactone, δ-jasmolactone, CO₂, and bicyclic epoxides, incorporate abundant and inexpensive metal carboxylates (Na(I), Zn(II), and Al(III)) into the midblock, forming reversible networks that enhance tensile strength by 150% while maintaining high strain at break (>1500%) and elastic recovery (>85%). The same cross-links act as built-in catalysts, enabling energy-efficient depolymerization of both polyester and polycarbonate domains at 200 °C, recovering the original monomers. This dual-function approach advances circular polymer design by combining enhanced performance with efficient, low-energy, closed-loop recycling.

Oxygenated block polymers, comprising esters and carbonates, are priority materials to replace petrochemical polymers in a circular plastics economy. These materials should repopulate the thermomechanical property space mapped by current plastics and elastomers. Here, a novel machine learning approach, PolyReco, predicts structures of oxygenated block polymers meeting the mechanical performance thresholds for widely used and hard-to-replace petroleum derived hydrocarbon polymers. Triblock oxygenated polymers are represented as graphs, and a link prediction algorithm enables feature extraction to identify new block polymer combinations, and associated degrees of polymerization, to meet the target properties. PolyReco is paired with a visualization tool for further material down selection based on user requirements. Three case studies highlight and experimentally validate its predictive power for identifying high-performance oxygenated block polymers, with new block polymers prepared and tested. These new block polymers exhibit tensile mechanical properties in the range of high-impact polystyrene, poly(dimethylsiloxane), and styrenic elastomers; the experimental results indicate that PolyReco may help support the identification of sustainable materials that could reduce dependence on fossil-based polymer incumbents.

Pressure sensitive adhesives (PSAs) are widely used materials in a number of applications, such as sticky notes and tapes, but for most commercial products they are derived from petrochemicals. Here, a series of pentablock polymers, with an ABABA structure featuring poly(cyclohexene oxide-alt-phthalic anhydride) ‘A’ blocks and poly(ε-decalactone) (PDL) ‘B’ blocks, are prepared as pressure-sensitive adhesives from bio-sourced monomers. The pentablock polymers are prepared by controlled polymerisation techniques, using a single catalyst, in a one-pot process. Polymer properties are tuned through varying the hard block (A) content between 16–39 wt%. Below 25 wt% hard block, the pentablock polymers show low-tack adhesive performance (0.2–0.6 N cm⁻¹) and are removed by adhesive failure. Their adhesive performance compares favourably to low-tack commercial adhesives.

Polyester thermoplastic elastomers are promising sustainable materials but their mechanical properties need improvement, in particular, attempts to increase strength often result in compromised elasticity. Strong and tough elastomers are known but require complex polymer formulations together with control over cross‐linking or crystallinity, both of which challenge recycling. Here, the introduction of transient strain‐stiffening approaches into fully amorphous structures show both strengthening and toughening of elastomers while conserving recyclability. The new amorphous block polyester elastomers are prepared by controlled polymerization methods using commercial monomers. The block polymers comprise a central poly(ɛ‐caprolactone‐ co ‐ɛ‐decalactone) block flanked by poly(cyclohexene oxide‐ alt ‐phthalate) blocks. Elastomer thermomechanical properties are tuned by varying ratios of ɛ‐caprolactone to ɛ‐decalactone within the mid‐block to access materials with excellent mechanical properties. The best elastomers feature 30–50 wt.% polycaprolactone and exhibit tensile strengths up to 40 MPa, elongations at break above 2000%, with excellent elastic recovery (>90%). These materials exhibit strain‐induced crystallization and outperform current commercial elastomers, entering a new region of tensile mechanical property space. They have service temperature ranges from −60 to 140 °C and high temperature stability (≥300 °C), with wide thermal (re)processing windows. These new polyester elastomers also show high resistance to creep, humidity resistance, and excellent recyclability.

Vat photopolymerization 3D printing has proven very successful for the rapid additive manufacturing (AM) of polymeric parts at high resolution. However, the range of materials that can be printed and their resulting properties remains narrow. Herein, we report the successful AM of a series of poly(carbonate‐b‐ester‐b‐carbonate) elastomers, derived from carbon dioxide and bio‐derived ϵ‐decalactone. By employing a highly active and selective Co(II)Mg(II) polymerization catalyst, an ABA triblock copolymer (M_n=6.3 kg mol⁻¹, Ð_M=1.26) was synthesized, formulated into resins which were 3D printed using digital light processing (DLP) and a thiol‐ene‐based crosslinking system. A series of elastomeric and degradable thermosets were produced, with varying thiol cross‐linker length and poly(ethylene glycol) content, to produce complex triply periodic geometries at high resolution. Thermomechanical characterization of the materials reveals printing‐induced microphase separation and tunable hydrophilicity. These findings highlight how utilizing DLP can produce sustainable materials from low molar mass polyols quickly and at high resolution. The 3D printing of these functional materials may help to expedite the production of sustainable plastics and elastomers with potential to replace conventional petrochemical‐based options.

Vat photopolymerization 3D printing has proven very successful for the rapid additive manufacturing (AM) of polymeric parts at high resolution. However, the range of materials that can be printed and their resulting properties remains narrow. Herein, we report the successful AM of a series of poly(carbonate‐b‐ester‐b‐carbonate) elastomers, derived from carbon dioxide and bio‐derived ϵ‐decalactone. By employing a highly active and selective Co(II)Mg(II) polymerization catalyst, an ABA triblock copolymer (M_n=6.3 kg mol⁻¹, Ð_M=1.26) was synthesized, formulated into resins which were 3D printed using digital light processing (DLP) and a thiol‐ene‐based crosslinking system. A series of elastomeric and degradable thermosets were produced, with varying thiol cross‐linker length and poly(ethylene glycol) content, to produce complex triply periodic geometries at high resolution. Thermomechanical characterization of the materials reveals printing‐induced microphase separation and tunable hydrophilicity. These findings highlight how utilizing DLP can produce sustainable materials from low molar mass polyols quickly and at high resolution. The 3D printing of these functional materials may help to expedite the production of sustainable plastics and elastomers with potential to replace conventional petrochemical‐based options.