The short lifespan of most commercial plastics as disposables and the failure to adequately address the end-of-life issues of synthetic polymers have led to outrageous global plastic pollution and resource depletion.T...The short lifespan of most commercial plastics as disposables and the failure to adequately address the end-of-life issues of synthetic polymers have led to outrageous global plastic pollution and resource depletion.To solve the problem,one of the most effective strategies is to develop circular polymers and thus establish a new circular material economy.Polymers from ring-opening polymerization of five-membered(thio)lactones contribute greatly to this field due to their excellent material performance and recyclability.The emerging topic emphasizes on the monomer design strategies based on five-membered(thio)lactones,and compares the thermal and mechanical properties and depolymerizability of the resulting polymers with different structures.展开更多
The molecular recyclability of poly (ethylene terephthalate) (PET) and three semi-aromatic polyesters poly (phloretic acid) (poly-H), poly (dihydroferulic acid) (poly-G), and poly (dihydrosinapinic acid) (poly-S) is e...The molecular recyclability of poly (ethylene terephthalate) (PET) and three semi-aromatic polyesters poly (phloretic acid) (poly-H), poly (dihydroferulic acid) (poly-G), and poly (dihydrosinapinic acid) (poly-S) is evaluated in this study. PET is an extensively used aromatic polyester, and poly-H, poly-G, and poly-S can be considered semi-aromatic poly (lactic acid) modifications. All these polyesters have been depolymerized at neutral pH and by acid- and base-catalyzed hydrolysis at two temperatures, i.e., 50˚C and 80˚C. Base-catalyzed depolymerization of virgin PET leads to an isolated yield of 38% after 48 hours of reaction at 80˚C. Contrary to these results for PET, almost all the monomers of the semi-aromatic polyesters poly-H, poly-G, and poly-S are recovered with isolated yields larger than 90% at the same temperature after 15 minutes in a facile manner. A shrinking particle model used to determine the global kinetics of the base-catalyzed depolymerization showed that the rate rises with increasing temperature. Using the shrinking particle model, the intrinsic reaction rate constants were determined. It has been demonstrated that the rate coefficients of the depolymerization of the semi-aromatic polyesters poly-H, poly-G, and poly-S are between 2 and 3 orders of magnitude higher than those for PET.展开更多
Polymer circularity has received increasing attention due to ecological benefits,by which plastic waste should be reused or converted into high-value products in an economic framework balanced with virgin polymer prod...Polymer circularity has received increasing attention due to ecological benefits,by which plastic waste should be reused or converted into high-value products in an economic framework balanced with virgin polymer production.From a chemical engineering point of view,the understanding of reaction kinetics and chemical modifications plays a crucial role in improving the process towards polymer circularity.This reaction kinetics is connected to molecular variations for which(micro)kinetic models are essential.In this perspective,the main kinetic simulation methods are summarized,focusing on their respective characteristics and challenges,besides differentiating between deterministic and stochastic methods.The application of kinetic simulations in polymer circularity processes is clarified in the form of three case studies,including(i)mechanical recycling with deliberate chemical modification by reactive extrusion,(ii)chemical recycling aiming at monomer recovery,and(iii)recycling-by-design aiming at vitrimer molecular design.Attention is also paid to the relevance of benchmarking the methods applied.展开更多
Whilst polymers have played a significant role in the development of modern society,a rapid growth of polymer waste is disadvantageously influencing communities and ecosystems across the world.Constructing a closed-lo...Whilst polymers have played a significant role in the development of modern society,a rapid growth of polymer waste is disadvantageously influencing communities and ecosystems across the world.Constructing a closed-loop life cycle of polymer materials is urgently in demand.Chemical recycling of polyesters,which can be recovered to the pristine monomers or transformed to other value-added products,has been considered as an appealing recycling approach to circular polymer economy and attracted enormous attention in the last several years.This review highlights some recent progress in the chemical recycling of diverse polyesters,including commercialized poly(lactic acid),poly(ε-caprolactone),poly(ethylene terephthalate),as well as various novel chemically recyclable polyesters and polycarbonates.Eventually,based on these technological developments,we discuss the remaining challenges and identify promising research opportunities,providing insights into future directions for achieving a genuine closed-loop polymer economy.展开更多
The global polymer industry encounters great challenges as plastic waste is generated and accumulated,causing severe plastic pollution in our environment.Conventional polymers are dependent on non-renewable fossil fee...The global polymer industry encounters great challenges as plastic waste is generated and accumulated,causing severe plastic pollution in our environment.Conventional polymers are dependent on non-renewable fossil feedstocks and are hard to recycle.This linear“produce-use-discard”pattern is no longer sustainable,and the development of circular polymer systems—materials that can be efficiently depolymerized,recycled,and transformed into high-value products—has emerged as a critical research frontier with significant environmental and economic implications[[1],[2],[3],[4],[5],[6],[7],[8]].Insightful perspectives and reviews are brought together in this special issue of Fundamental Research,“Polymer Depolymerization,Recycling,and High-value Transformation.”The collection highlights innovative chemical strategies,emerging technologies,and interdisciplinary approaches reshaping our understanding of polymer sustainability.By presenting work from leading researchers,this issue aims to advance the development of circular polymer systems and inspire new solutions to the plastic waste crisis.展开更多
Polymers have become an essential part of modern life and the global economy on account of their costeffectiveness and versatile properties.However,most postconsumer polymer wastes are unrecycled,leading to environmen...Polymers have become an essential part of modern life and the global economy on account of their costeffectiveness and versatile properties.However,most postconsumer polymer wastes are unrecycled,leading to environmental pollution and resource wastage.Depolymerization,as an efficient chemical recycling approach,holds great promise in establishing a circular polymer economy.In this review,we attempt to highlight recent and significant advancements in depolymerization methodologies.Two key research topics are discussed:(1)depolymerization of commodity polymers to produce reusable monomers and high-value chemicals;(2)depolymerization of intrinsically depolymerizable polymers.It is anticipated that this review will reflect the present status and future trends of this rapidly evolving realm of depolymerization.展开更多
基金supported by the National Natural Science Foundation of China(No.52173093)Peking University Ge Li and Ning Zhao Life Science Research Fund for Young Scientists.
文摘The short lifespan of most commercial plastics as disposables and the failure to adequately address the end-of-life issues of synthetic polymers have led to outrageous global plastic pollution and resource depletion.To solve the problem,one of the most effective strategies is to develop circular polymers and thus establish a new circular material economy.Polymers from ring-opening polymerization of five-membered(thio)lactones contribute greatly to this field due to their excellent material performance and recyclability.The emerging topic emphasizes on the monomer design strategies based on five-membered(thio)lactones,and compares the thermal and mechanical properties and depolymerizability of the resulting polymers with different structures.
文摘The molecular recyclability of poly (ethylene terephthalate) (PET) and three semi-aromatic polyesters poly (phloretic acid) (poly-H), poly (dihydroferulic acid) (poly-G), and poly (dihydrosinapinic acid) (poly-S) is evaluated in this study. PET is an extensively used aromatic polyester, and poly-H, poly-G, and poly-S can be considered semi-aromatic poly (lactic acid) modifications. All these polyesters have been depolymerized at neutral pH and by acid- and base-catalyzed hydrolysis at two temperatures, i.e., 50˚C and 80˚C. Base-catalyzed depolymerization of virgin PET leads to an isolated yield of 38% after 48 hours of reaction at 80˚C. Contrary to these results for PET, almost all the monomers of the semi-aromatic polyesters poly-H, poly-G, and poly-S are recovered with isolated yields larger than 90% at the same temperature after 15 minutes in a facile manner. A shrinking particle model used to determine the global kinetics of the base-catalyzed depolymerization showed that the rate rises with increasing temperature. Using the shrinking particle model, the intrinsic reaction rate constants were determined. It has been demonstrated that the rate coefficients of the depolymerization of the semi-aromatic polyesters poly-H, poly-G, and poly-S are between 2 and 3 orders of magnitude higher than those for PET.
基金support from the National Natural Science Foundation of China(21625603,22078195,22222807,22238005)support from FWO Vlaanderen(G.0H52.16 N and G027122 N).
文摘Polymer circularity has received increasing attention due to ecological benefits,by which plastic waste should be reused or converted into high-value products in an economic framework balanced with virgin polymer production.From a chemical engineering point of view,the understanding of reaction kinetics and chemical modifications plays a crucial role in improving the process towards polymer circularity.This reaction kinetics is connected to molecular variations for which(micro)kinetic models are essential.In this perspective,the main kinetic simulation methods are summarized,focusing on their respective characteristics and challenges,besides differentiating between deterministic and stochastic methods.The application of kinetic simulations in polymer circularity processes is clarified in the form of three case studies,including(i)mechanical recycling with deliberate chemical modification by reactive extrusion,(ii)chemical recycling aiming at monomer recovery,and(iii)recycling-by-design aiming at vitrimer molecular design.Attention is also paid to the relevance of benchmarking the methods applied.
基金support from the National Natural Science Foundation of China(22231008,52103001,and 22071167)the Natural Science Foundation of Jiangsu Higher Education Institutions of China(22KJA150005)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions is gratefully acknowledged.
文摘Whilst polymers have played a significant role in the development of modern society,a rapid growth of polymer waste is disadvantageously influencing communities and ecosystems across the world.Constructing a closed-loop life cycle of polymer materials is urgently in demand.Chemical recycling of polyesters,which can be recovered to the pristine monomers or transformed to other value-added products,has been considered as an appealing recycling approach to circular polymer economy and attracted enormous attention in the last several years.This review highlights some recent progress in the chemical recycling of diverse polyesters,including commercialized poly(lactic acid),poly(ε-caprolactone),poly(ethylene terephthalate),as well as various novel chemically recyclable polyesters and polycarbonates.Eventually,based on these technological developments,we discuss the remaining challenges and identify promising research opportunities,providing insights into future directions for achieving a genuine closed-loop polymer economy.
文摘The global polymer industry encounters great challenges as plastic waste is generated and accumulated,causing severe plastic pollution in our environment.Conventional polymers are dependent on non-renewable fossil feedstocks and are hard to recycle.This linear“produce-use-discard”pattern is no longer sustainable,and the development of circular polymer systems—materials that can be efficiently depolymerized,recycled,and transformed into high-value products—has emerged as a critical research frontier with significant environmental and economic implications[[1],[2],[3],[4],[5],[6],[7],[8]].Insightful perspectives and reviews are brought together in this special issue of Fundamental Research,“Polymer Depolymerization,Recycling,and High-value Transformation.”The collection highlights innovative chemical strategies,emerging technologies,and interdisciplinary approaches reshaping our understanding of polymer sustainability.By presenting work from leading researchers,this issue aims to advance the development of circular polymer systems and inspire new solutions to the plastic waste crisis.
基金supported by the National Natural Science Foundation of China(grant nos.22193020 and 22193021).
文摘Polymers have become an essential part of modern life and the global economy on account of their costeffectiveness and versatile properties.However,most postconsumer polymer wastes are unrecycled,leading to environmental pollution and resource wastage.Depolymerization,as an efficient chemical recycling approach,holds great promise in establishing a circular polymer economy.In this review,we attempt to highlight recent and significant advancements in depolymerization methodologies.Two key research topics are discussed:(1)depolymerization of commodity polymers to produce reusable monomers and high-value chemicals;(2)depolymerization of intrinsically depolymerizable polymers.It is anticipated that this review will reflect the present status and future trends of this rapidly evolving realm of depolymerization.
