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The low thermal conductivity, poor toughness, and non‐reprocessability of thermosetting epoxy resins severely restrict their applications and sustainable development in flexible electronics. Herein, liquid crystalline epoxy (LCE) and dynamic ester and disulfide bonds are introduced into the cured network of bisphenol A epoxy resin (E‐51) to construct highly thermally conductive flexible liquid crystalline epoxy resin (LCER) vitrimers. LCER vitrimers demonstrate adjustable mechanical properties by varying the ratio of LCE to E‐51, allowing it to transition from soft to strong. Typically, a 75 mol% LCE to 25 mol% E‐51 ratio results in an in‐plane thermal conductivity (λ) of 1.27 W m−1 K−1, over double that of pure E‐51 vitrimer (0.61 W m−1 K−1). The tensile strength and toughness increase 2.88 folds to 14.1 MPa and 2.45 folds to 20.1 MJ m−3, respectively. Besides, liquid crystalline phase transition and dynamic covalent bonds enable triple shape memory and three‐dimensional shape reconstruction. After four reprocessing cycles, λ and tensile strength remain at 94% and 72%, respectively. Integrating carbon nanotubes (CNTs) imparts photo‐thermal effect and enables “on” and “off” switch under near‐infrared light to LCER vitrimer. Furthermore, the CNTs/LCER vitrimer displays light‐induced actuation, self‐repairing, and self‐welding besides the closed‐loop recycling and rapid degradation performance. The combination of liquid crystalline epoxy and dynamic covalent bonds creates highly thermally conductive liquid crystalline epoxy resin (LCER) vitrimers with multi‐shape memory and closed‐loop recycling capabilities. The 0.5 wt% introduced carbon nanotubes enable LCER vitrimers with photothermal conversion and near‐infrared light‐induced actuation, providing insights for designing recyclable materials with special functions, such as soft actuators and intelligent wearable electronics.

With an ever-increasing demand for energy, there is a proportionate increase in energy storage devices, among which batteries hold the key to the energy transition. Globally, batteries constitute the fastest-growing energy storage technology that is playing a key role in the transport sector electrification leading to rising demand for LIBs. However, there is a substantial need for innovation that will help mitigate the environmental effects of the production and use of LIBs—such as energy use, mineral extraction, and chemical processing. The battery value chain can be seen as an exceptional sustainable value creation opportunity wherein sustainability depends in part on the ability to reuse and recycle batteries. A typical LIB battery serves in electric vehicles (EVs) for about 5–10 years and needs to be replaced when they reach ~ 20% capacity loss. At this stage, the fate of the battery follows one of the routes—disposal, reuse/repurpose/remanufacture (3R) or recycle. However, a major obstacle for car and battery manufacturers to invest in second life, or to otherwise take advantage of the reuse market, is that they in many cases do not have control over the batteries. On the other hand, recycling LIBs holds tremendous potential owing to the recirculation of materials i.e., closed-loop recycling needed for battery manufacturing promoting sustainability. This review will enable readers to devise processes that contribute to closing the loop of the EV LIBs value chain from an industrial perspective as well as critically understand the current state and future of battery recycling. Graphical Abstract

Low‐density polyethylene (LDPE) is one of the most important plastics, which is produced unfortunately under extreme conditions. In addition, it consists of robust aliphatic C─C bonds which are challenging to cleave for plastic recycling. A low‐pressure and ‐temperature (pethylene = 2 bara, T = 70 °C) macromonomer‐based synthesis of long chain branched polyethylene is reported. The introduction of recycle points permits the polymerization (grafting to) of the macromonomers to form the long chain branched polyethylene and its depolymerization (branch cleavage). Coordinative chain transfer polymerization employing ethylene and co‐monomers is used for the synthesis of the macromonomers, permitting a high flexibility of their precise structure and efficient synthesis. The long chain branched polyethylene material matches key properties of low‐density polyethylene. Controlled and efficient ethylene copolymerization via coordinative chain transfer polymerization permits the synthesis of low density polyethylene materials that contain recycle points. The syntheses proceed under mild conditions and the recycle points permit closed‐loop recycling of the plastic.

Developing recyclable, multifunctional air purification materials that minimize environmental impact represents a grand challenge in the pursuit of carbon neutrality. Herein, a multifunctional air filtration membrane is prepared through a thermally induced precursor crystallization (TIPC) process that drives the self‐assembly of a supramolecular nanofibrous network from melamine (MA) and trimesic acid (TMA). Graphene oxide (GO) nanosheets, strategically incorporated as heterogeneous nucleation‐templating agents, are critical for tailoring the hierarchical network morphology and endowing the membrane with multiple synergistic properties. The resulting membrane delivers exceptional particulate matter (PM) filtration efficiency (99.48% for PM1.0), potent antimicrobial activity against (Escherichia coli) E. coli (99.4%) and (Staphylococcus aureus) S. aureus (99.8%), and a high formaldehyde removal capacity (95%). Beyond purification, the membrane also demonstrates effective thermal management for wearer comfort and superior UV‐blocking (< 0.4% transmittance). Crucially, the inherent thermoreversibility of the supramolecular network enables complete, closed‐loop recycling of the membrane using only green solvents under mild conditions. This work presents a comprehensive and sustainable strategy for preparing advanced air filtration materials, demonstrating that high performance, integrated multifunctionality, and complete lifecycle circularity can be co‐designed from the molecular level up. A green, thermoreversible self‐assembly strategy yields a multifunctional and recyclable supramolecular nanofibrous membrane. Graphene oxide (GO) nanosheet acts as a heterogeneous nucleation‐templating agent, simultaneously modulating the supramolecular crystal packing while tailoring the nanofibrous architecture for elite performance. The resulting membrane provides exceptional PM filtration, antimicrobial activity, HCHO capture, robust UV‐shielding, and effective thermal management, all while retaining complete closed‐loop recyclability.

Water bottles are widely used in the Gulf countries. One estimate indicates that the water bottle usage in the United Arab Emirates (UAE) may reach up to 250 L of water per person annually. Generally, the water bottles are made of polyethylene terephthalate (PET), a recyclable material. Because of the non-availability of a powerful incentive system, these recyclable water bottles are often disposed of in landfills. This paper proposes a feasibility study of building a Deposit–Refund System (DRS) to encourage the closed-loop recycling of 0.5 L PET water bottles in the UAE waste disposal system. Water bottles are collected by a reverse vending machine (RVM) and recycled to produce PET bottles, and the proposed system will reward consumers with 0.04 United Arab Emirates Dirham (AED) per deposited water bottle. Additionally, this study calculates the cost of 100% virgin polyethylene terephthalate (vPET) and 60% recycled polyethylene terephthalate (rPET) bottles based on the UAE population, data obtained from local water bottle companies, and existing research. Adopting this DRS will cut down on waste, protect the environment, improve the manufacturing process of water bottles, and boost the local economy.

Chemical recycling of polymers is critical for improving the circular economy of plastics and environmental sustainability. Traditional thermoset polymers have generally been considered permanently crosslinked materials that are difficult or impossible to recycle. Herein, we demonstrate that by activating ‘dormant’ covalent bonds, traditional polycyanurate thermosets can be recycled into the original monomers, which can be circularly reused for their original purpose. Through retrosynthetic analysis, we redirected the synthetic route from forming conventional C–N bonds via irreversible cyanate trimerization to forming the C–O bonds through reversible nucleophilic aromatic substitution of alkoxy-substituted triazine derivatives by alcohol nucleophiles. The new reversible synthetic route enabled the synthesis of previously inaccessible alkyl-polycyanurate thermosets, which exhibit excellent film properties with high chemical resistance, closed-loop recyclability and reprocessing capability. These results show that ‘apparently dormant’ dynamic linkages can be activated and utilized to construct fully recyclable thermoset polymers with a broader monomer scope and increased sustainability. Alkyl and aryl polycyanurate networks have now been prepared through polymerization of diols and substituted triazines via a dynamic S N Ar reaction. When treated with excess mono alcohol or phenol, the polycyanurate networks can be depolymerized into the starting monomers, which can be separated and reused, thus achieving closed-loop recycling.

To reduce environmental pollution and reliance on fossil resources, polyethylene terephthalate as the most consumed synthetic polyester needs to be recycled effectively. However, the existing recycling methods cannot process colored or blended polyethylene terephthalate materials for upcycling. Here we report a new efficient method for acetolysis of waste polyethylene terephthalate into terephthalic acid and ethylene glycol diacetate in acetic acid. Since acetic acid can dissolve or decompose other components such as dyes, additives, blends, etc., Terephthalic acid can be crystallized out in a high-purity form. In addition, Ethylene glycol diacetate can be hydrolyzed to ethylene glycol or directly polymerized with terephthalic acid to form polyethylene terephthalate, completing the closed-loop recycling. Life cycle assessment shows that, compared with the existing commercialized chemical recycling methods, acetolysis offers a low-carbon pathway to achieve the full upcycling of waste polyethylene terephthalate. The recycling of polyethylene terephthalate is of utmost importance to reduce environmental pollution and reliance on fossil resources however, the existing methods do not process colored or blended polyethylene terephthalate materials. Here, the authors demonstrate the acetolysis of waste polyethylene terephthalate into terephthalic acid and simultaneous acidic degradation of dyes and additives

Recycled plastics are low-value commodities due to residual impurities and the degradation of polymer properties with each cycle of re-use. Plastics that undergo reversible polymerization allow high-value monomers to be recovered and re-manufactured into pristine materials, which should incentivize recycling in closed-loop life cycles. However, monomer recovery is often costly, incompatible with complex mixtures and energy-intensive. Here, we show that next-generation plastics—polymerized using dynamic covalent diketoenamine bonds—allow the recovery of monomers from common additives, even in mixed waste streams. Poly(diketoenamine)s ‘click’ together from a wide variety of triketones and aromatic or aliphatic amines, yielding only water as a by-product. Recovered monomers can be re-manufactured into the same polymer formulation, without loss of performance, as well as other polymer formulations with differentiated properties. The ease with which poly(diketoenamine)s can be manufactured, used, recycled and re-used—without losing value—points to new directions in designing sustainable polymers with minimal environmental impact. It is difficult to recover materials for re-manufacturing and re-use from plastics that are compounded with colourants, fillers and flame retardants. Now, it has been shown that alternative plastics based on dynamic covalent poly(diketoenamine)s depolymerize in strong aqueous acids and enable triketone and amine monomers to be isolated and upcycled into new plastics.

Sustainable battery recycling is essential for achieving resource conservation and alleviating environmental issues. Many open/closed-loop strategies for critical metal recycling or direct recovery aim at a single component, and the reuse of mixed cathode materials is a significant challenge. To address this barrier, here we propose an upcycling strategy for spent LiFePO 4 and Mn-rich cathodes by structural design and transition metal replacement, for which uses a green deep eutectic solvent to regenerate a high-voltage polyanionic cathode material. This process ensures the complete recycling of all the elements in mixed cathodes and the deep eutectic solvent can be reused. The regenerated LiFe 0.5 Mn 0.5 PO 4 has an increased mean voltage (3.68 V versus Li/Li + ) and energy density (559 Wh kg –1 ) compared with a commercial LiFePO 4 (3.38 V and 524 Wh kg –1 ). The proposed upcycling strategy can expand at a gram-grade scale and was also applicable for LiFe 0.5 Mn 0.5 PO 4 recovery, thus achieving a closed-loop recycling between the mixed spent cathodes and the next generation cathode materials. Techno-economic analysis shows that this strategy has potentially high environmental and economic benefits, while providing a sustainable approach for the value-added utilization of waste battery materials. Direct recycling of critical battery materials bring promise but a challenge for the mixed cathode chemistries. Here, the authors report a sustainable upcycling approach, transforming degraded LiFePO 4 and Mn-rich cathodes into a high-voltage polyanionic material with an increased energy density and economic value.

Alcoholysis of poly(ethylene terephthalate) (PET) waste to produce monomers, including methanolysis to yield dimethyl terephthalate (DMT) and glycolysis to generate bis-2-hydroxyethyl terephthalate (BHET), is a promising strategy in PET waste management. Here, we introduce an efficient PET-alcoholysis approach utilizing an oxygen-vacancy ( V o )-rich catalyst under air, achieving space time yield (STY) of 505.2 g DMT ·g cat −1 ·h −1 and 957.1 g BHET ·g cat −1 ·h −1 , these results represent 51-fold and 28-fold performance enhancements compared to reactions conducted under N 2 . In situ spectroscopy, in combination with density functional theory calculations, elucidates the reaction pathways of PET depolymerization. The process involves O 2 -assisted activation of CH 3 OH to form CH 3 OH * and OOH * species at V o -Zn 2+ –O–Fe 3+ sites, highlighting the critical role of V o -Zn 2+ –O–Fe 3+ sites in ester bond activation and C–O bond cleavage. Moreover, a life cycle assessment demonstrates the viability of our approach in closed-loop recycling, achieving 56.0% energy savings and 44.5% reduction in greenhouse-gas emissions. Notably, utilizing PET textile scrap further leads to 58.4% reduction in initial total operating costs. This research offers a sustainable solution to the challenge of PET waste accumulation. Polyester waste is increasingly accumulating in the environment, and alcoholysis recycling offers a sustainable management solution. This study demonstrates the use of an oxygen vacancy-rich catalyst to transform waste blended polyester/textiles into high-value monomers.