Recyclable polymers offer a great opportunity to address the environmental issues of plastics.Herein,functionalization of recyclable polymers,poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),were reported via...Recyclable polymers offer a great opportunity to address the environmental issues of plastics.Herein,functionalization of recyclable polymers,poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),were reported via end-group modifications and block/random copolymerizations.Di-n-butylmagnesium was selected to catalyze ring-opening polymerization(ROP)of(R)-M in the presence of a series of functional alcohols as the initiators.Block/random copolymerizations of(R)-M andε-caprolactone(ε-CL),L-lactide(L-LA)and trimethylene carbonate(TMC)were performed to control the onset decomposition temperature(T_(d)),melting temperature(T_(m))and glass transition temperature(T_(g)).These functionalized recyclable polymers would find broad applications as the sustainable plastics.展开更多
The development of modern society is closely related to polymer materials.However,the improper disposal of the polymer wastes not only squanders resources but also intensifies the environmental issues,despite that ene...The development of modern society is closely related to polymer materials.However,the improper disposal of the polymer wastes not only squanders resources but also intensifies the environmental issues,despite that energy recovery,physical recycling and chemical recycling pathways have been developed to tackle the recycle and reuse of polymers.Among them,chemical recycling is considered as the most pivotal solution,as it can depolymerize the polymer wastes back to monomers,which then repolymerize into polymer materials.Recently,remarkable progress has been made in the development of chemically recyclable polymers through monomer design to shift“polymerization-depolymerization”equilibrium to realize the selective depolymerization of the polymers into monomers,and to achieve chemical recycling closed-loop.This article reviews the closed-loop polymers such as polyesters,polycarbonates,sulfur-containing polymers,vinyl monomer-based polymers as well as other types of polymers.Moreover,the challenges and prospects in this field are also discussed.展开更多
Developing polymers that can be chemically recycled signifies a considerable prospect to polymer scientists to tackle the increasing plastic crises but is still plagued with certain limitations in architecture/perform...Developing polymers that can be chemically recycled signifies a considerable prospect to polymer scientists to tackle the increasing plastic crises but is still plagued with certain limitations in architecture/performance diversity and depolymerization activity.Polythioesters synthesized through ring-opening polymerization(ROP)of cyclic thioesters monomers are captivating materials owing to the labile thioester bonds in polymer chains and the low ring strain energy of thiolactone monomers.In this brief review,the latest advancements in the ring-opening polymerization of dithiolactone and monothiodilactone monomers to prepare chemically recycled polythioesters are summarized.Moreover,the feasibility and challenges in future practical applications of chemically recyclable polythioesters derived from dithiolactone and monothiodilactone will be discussed.展开更多
Chiral bisoxazoline(box)ligands with indene groups at C4 and C5 are highly potent in asymmetric catalysis,but face challenges in terms of cost and recyclability.To address this,we have designed polystyrene-supported b...Chiral bisoxazoline(box)ligands with indene groups at C4 and C5 are highly potent in asymmetric catalysis,but face challenges in terms of cost and recyclability.To address this,we have designed polystyrene-supported box ligands by modifying the indene moiety instead of the traditional methylene bridge.This design preserves the necessary steric environment for copper coordination,enabling high efficiency and excellent enantioselectivity as examined in photoinduced asymmetric cyanation reactions.The resulting copper complexes are robust and recyclable,maintaining performance over five cycles.This approach provides a sustainable and practical solution for asymmetric catalysis with chiral box ligands.展开更多
The fabrication of liquid-free ionic conductive elastomers(ICEs)that can function as flexible temperature sensors with high sensitivity,fast response time,and efficient recyclability is a great challenge.In this study...The fabrication of liquid-free ionic conductive elastomers(ICEs)that can function as flexible temperature sensors with high sensitivity,fast response time,and efficient recyclability is a great challenge.In this study,novel liquid-free ICEs are conveniently fabricated through the complexation of 4-carboxybenzaldehyde-grafted poly(vinyl alcohol)(CPVA)with well-designed solid quaternary ammonium(QA)molecules bearing bifunctional hydrogen-bonding moieties.The resulting CPVA-QA elastomers,which are highly elastic and adhesive to diverse surfaces,exhibit a tensile strength of 6.6 MPa,a toughness of 14.7 MJ m^(-3),and a Young’s modulus of 0.15 MPa.These elastomers have a hydrogen-bonded network structure where the bifunctional QA molecules significantly suppress polymer chain entanglements.Benefitting from the thermally sensitive hydrogen bonds and the substantially reduced chain entanglements,the CPVA-QA elastomers show a high chain mobility upon temperature elevation,which facilitates ion transport within the CPVA-QA elastomers.Consequently,the CPVA-QA elastomer-based temperature sensors show an outstanding temperature resolution(0.05℃),a fast response time over a wide temperature range,and a record-high thermosensitivity of 10.8%K-1.Importantly,the CPVA-QA sensors can be depolymerized under mild conditions to recover their original components in high purity and yields(>96%),enabling closed-loop recycling of the sensors.展开更多
PU （polyurethane） integral skin and PVC （polyvinyl chloride） are polymeric materials which have favorable physical characteristics to reduce the impact noise when applied to floor systems. In civil construction, f...PU （polyurethane） integral skin and PVC （polyvinyl chloride） are polymeric materials which have favorable physical characteristics to reduce the impact noise when applied to floor systems. In civil construction, floating floors systems are composed of two layers above the slab： a resilient layer and, above this, a rigid layer of cement matrix that works as a subfloor. This research aims to evaluate the incorporation of PVC and PU skin waste in the resilient layer of the floating floor, for impact noise insulation. It was conducted physical, mechanical and morphological tests in the composite, as SEM （scanning electron microscopy）, determination of compressive creep, and impact noise test to evaluate the absorption capacity of the floor system over time. Furthermore, experimental results were compared with theoretical studies. These correlations may assist in understanding the behavior of impact noise damping and its relation to the size of the samples.展开更多
In this article, based on the analysis of the current environmental situation in Russia and other countries, as well as of the problem of recycling plastic waste in the Russian Federation （RF）, the authors clearly s...In this article, based on the analysis of the current environmental situation in Russia and other countries, as well as of the problem of recycling plastic waste in the Russian Federation （RF）, the authors clearly show the effectiveness of investments in the processing of polymer debris on the example of polyethylene terephthalate （PET） waste （granulates, flakes）. In the frame of case study of social and environmental investment project on creating enterprise that will engage in collection, recycling, and sale of the consumer PET packaging in Russia, the authors demonstrate the economic feasibility of the creation of such kind of enterprises taking into account market conditions and the features of the existing system of taxation in Russia. The realization of the project will also help in solving environmental and social problems of large cities, in particular, will create more jobs （in terms of 6% of unemployment rate in the country）. The study also identifies the main obstacles in the way of waste recycling in Russia, and the recommendations for improvement of normative base of the industry are given.展开更多
Polypropylene(PP)has become the focus of research and development of recyclable polymer dielectric materials because of its excellent electrical and thermal properties.The residual catalyst after PP polymerisation is ...Polypropylene(PP)has become the focus of research and development of recyclable polymer dielectric materials because of its excellent electrical and thermal properties.The residual catalyst after PP polymerisation is the main part of ash.It was found that ash particles are uniformly dispersed in the PP matrix.The increase in ash content leads to a gradual decrease in their spacing,and leads to a significant decrease in electrical prop-erties,with a difference of more than one order of magnitude for volume resistivity.The decrease in the ion migration potential barrier caused by the increase of ash content is the key factor in deteriorating the electrical properties of PP.The effect of ash on the elec-trical properties of PP mainly lies in enhancing the migration of ion carriers.The PP volume resistivity corresponds to an ash threshold of 292 ppm,above which the con-centration leads to an increase in ion carriers.The accumulation of carriers leads to in-ternal electric field distortion enhancing the transition ability of carriers and leading to a rapid decrease in the electrical properties of PP.This study provides a feasible reference for the development of high-performance PP insulation materials for power cables and other applications.展开更多
Researchers are pursuing promising chemically recyclable polymers.Here,we demonstrate a series of recyclable Se-containing polyesters from the first reported cascade multicomponent polymerization of elemental Se,H_(2)...Researchers are pursuing promising chemically recyclable polymers.Here,we demonstrate a series of recyclable Se-containing polyesters from the first reported cascade multicomponent polymerization of elemental Se,H_(2)O,CO,and diacrylate.The polymerization is considered to be through a cascade mechanism:Se is first reduced by CO to COSe;COSe is then reduced by H_(2)O to H_(2)Se;H_(2)Se is finally coupled with diacrylate to form a polymer.The method uses common organic bases as a catalyst and is performed under mild conditions with high yields.The obtained polymer is thermally stable with a tunable melting point,and can be easily depolymerized to Se and diacrylate by H_(2)O_(2) under mild conditions.Owing to the versatile synthesis,the structure/properties of the polymer are scalable,such as P4 and P5 with high-density polyethylene-like mechanical performance.Overall,the polymer is a promising material owing to its modular synthesis,practical recyclability,scalable performance,and commercial raw materials.展开更多
Mixed matrix membranes(MMMs)are designed by incorporating microporous inorganic fillers into polymer matrix for the integration of inorganics’excellent gas separation performance with polymers’promising flexibility....Mixed matrix membranes(MMMs)are designed by incorporating microporous inorganic fillers into polymer matrix for the integration of inorganics’excellent gas separation performance with polymers’promising flexibility.However,due to the complex interphase interaction,the prevention of long-term aging is still challenging and the poor processability/recyclability of MMMs hinders their extensive applications.Herein,a coordination assembly protocol is developed for the fabrication of MMMs with both excellent processability/recyclability upon thermal annealing and promising dimension stability even under high gas pressure.Polymers bearing isophthalic acid(IPA)as side chains are applied to coordinate with Cu^(2+)and the assembled 2.5 nm microporous metal-organic polyhedra(MOP),{Cu_(24)IPA_(24)},serves as multi-functional cross-linkers for the polymer network formation.The MOPs’well-defined microporosity grants MMMs the capability for O_(2)/N_(2) separation while their activated dynamics at high temperatures(>120℃)endows polymer networks with excellent processability.In contrast to conventional supramolecular units,the MOPs possess unique logarithmic ligand-exchange kinetics and they show nearly frozen bonding dynamics at room temperature,ensuring promising dimensional stability to overcome the long-term aging and high gas pressure effect.This work not only provides fundamental understanding of the unique relaxation dynamics of complex systems with intertwined dynamics of supramolecular bonds and polymer chains,but also paves new avenues for the fabrication of robust and recyclable MMMs and elastomers.展开更多
Copolymerization as an efficient strategy can provide an opportunity to create new closed-loop recyclable polymeric materials with tailored properties that are generally inaccessible to the individual homopolymers.In ...Copolymerization as an efficient strategy can provide an opportunity to create new closed-loop recyclable polymeric materials with tailored properties that are generally inaccessible to the individual homopolymers.In this contribution,the bulk ring-opening copolymerization of bio-renewable-caprolactone and trans-hexahydro-(4,5)-benzofuranone was achieved to produce closed-loop recyclable copolyesters by using an organobase/urea binary catalyst at room temperature.The obtained copolyesters exhibited composition-dependent thermal properties.Remarkably,the obtained copolyesters were able to depolymerize back to recover the corresponding monomers under mild conditions.展开更多
Traditional flame-retardant plastics are technically difficult to chemically recycle.The development of newtypes of flame-retardant plastics that are intrinsically capable of being closed-loop recycled and are suffici...Traditional flame-retardant plastics are technically difficult to chemically recycle.The development of newtypes of flame-retardant plastics that are intrinsically capable of being closed-loop recycled and are sufficiently robust and stable to satisfy their practical application is urgently needed.In this study,closed-loop recyclable flame-retardant plastics with high mechanical strength and excellent chemical resistance are fabricated by cross-linking amino-terminated polyimide(PI-NH_(2))and aldehyde-terminated cyclophosphazene(CP-CHO)with imine bonds.The resultant flame-retardant plastic,which is denoted as PI-CP,exhibits a tensile strength of∼115.6 MPa,Young’s modulus of∼2.5 GPa,and glass transition temperature of 316°C.In the PI-CP plastic,the imine bonds are isolated within hydrophobic microenvironments generated by the rigid and hydrophobic polyimide chains and the benzene ring of cyclophosphazenes.As a result,the PI-CP plastics are highly stable in highly acidic and basic aqueous solutions and other commonly used organic solvents.The PI-CP plastic shows outstanding flame retardancy with a limiting oxygen index value of 48.8%.More importantly,the PI-CP plastic can be depolymerized to generate the original PI-NH_(2)and CPCHO monomers in high yields(∼97%)and purity.The recovered monomers can be used to refabricate the original plastics,establishing highly efficient polymer-monomer-polymer circulation and a sustainable plastics economy.展开更多
The extensive use of plastics,valued for their lightweight,durability,and cost-effectiveness,has led to severe environmental pollution,with 72%of plastic waste ending up in landfills or natural habitats.Traditional me...The extensive use of plastics,valued for their lightweight,durability,and cost-effectiveness,has led to severe environmental pollution,with 72%of plastic waste ending up in landfills or natural habitats.Traditional methods for plastic decomposition,including both mechanical and chemical approaches,often face challenges such as incomplete degradation and stability concerns.The innovative concept of mechanical gating presents a promising solution by incorporating mechanophores into polymer structures,enabling controlled degradation.Recent advancements have focused on utilizing mechanophores,such as cyclobutane,as"door locks"to regulate the degradation process.This perspective highlights recent progress in this field,demonstrating the potential of mechanophore-based strategies for achieving on-demand polymer degradation.It addresses the limitations of conventional recycling methods and explores how this approach can balance polymer stability with environmental degradability,paving the way for more sustainable plastic management solutions.展开更多
Comprehensive Summary Introducing covalently crosslinked network to telechelic polymers can enable the formation of advanced polymeric materials with enhanced material properties.In this contribution,well-defined tele...Comprehensive Summary Introducing covalently crosslinked network to telechelic polymers can enable the formation of advanced polymeric materials with enhanced material properties.In this contribution,well-defined telechelic polymers bearing acetoacetate groups were synthesized via Ru-catalyzed ring-opening metathesis polymerization of cyclooctene in the presence of chain transfer agents.Given the unique feature of muti-site reactive acetoacetate end groups,several crosslinked networks were constructed using different crosslinkers under mild conditions.In the Michael addition reaction system,the introduction of di/trifunctional aliphatic acrylate as crosslinkers significantly enhanced the mechanical properties of the generated crosslinked network(tensile strength up to 27 MPa,elongation at break up to 500%).On the other hand,vitrimers with dynamic covalent crosslinked networks were accessed via transamination of vinylogous urethane reaction using telechelic polymers and tris(2-aminoethyl)amine.展开更多
Comprehensive Summary,Although polyimides(PIs)have shown great potential for a broad range of applications,it remains very challenging to achieve the malleability,rehealability and recyclability for PIs and their comp...Comprehensive Summary,Although polyimides(PIs)have shown great potential for a broad range of applications,it remains very challenging to achieve the malleability,rehealability and recyclability for PIs and their composites targeting various applications,particularly for the rapidly emerging flexible and stretchable electronics.Herein,malleable conductive poly(imide-imine)hybrid(PIIH)vitrimer-graphene aerogel(GA)composites have been prepared,for the first time,via simple sol-gel film formation followed by heat-press.The resulting PIIH-GA composites exhibit not only the highly desired properties of thermosetting(strong mechanical strength)and thermoplastic(reprocessability)polymers,but also good conductivity enabled by the GA filler.PIIH3-GA-10(with 10 wt%GA)showed one of the highest electrical conductivities(26.7 S/m)for PI-based composites,as well as good electromagnetic interference(EMI)shielding performance.Moreover,the PIIH-GA films could maintain good performance during stretching and even after chemical recycling,which opens new opportunities for flexible and sustainable electronics development.展开更多
Plastics are integral to numerous significant social advancements.Nonetheless,their contribution to environmental pollution and climate crises cannot be disregarded,as their negative impact on the environment increase...Plastics are integral to numerous significant social advancements.Nonetheless,their contribution to environmental pollution and climate crises cannot be disregarded,as their negative impact on the environment increases with incremental production capacity and demand.Concerted global action is urgently required to promote the green recycle of plastics to prevent their accumulation in the environment and mitigate carbon emissions.This review aims to reveal the paths of green development for polyester plastics,incorporating the trends of the green revolution in mature commercial polyester plastics,newly emerging biodegradable polyester plastics,and future polyester plastics.A critical discussion was conducted on the current and potential future research areas from multiple perspectives,including raw materials,processes,and recycling,to propel us into a future marked by sustainability.展开更多
Developing new chemically recyclable polymers is important for a circular plastics economy.Herein,we prepared a class of 1,4-dithian-2-one(DTO)with thioether and thioester functionalities.These sulfur-substituted mono...Developing new chemically recyclable polymers is important for a circular plastics economy.Herein,we prepared a class of 1,4-dithian-2-one(DTO)with thioether and thioester functionalities.These sulfur-substituted monomers(DTO)showed excellent reactivity for ring-opening polymerization(turnover frequency(TOF)up to 2.3×10^(4)h^(-1)),which afforded poly(thioetherthioester)s(P(DTO)s)with high air stability,high crystallinity,and commercial high-density polyethylene-like mechanical property(σB=29.59±1.08 MPa andεB=749%±36%).Intriguingly,chemical recycling of P(DTO)to monomer could be accomplished with excellent efficiency in dilute solution(1 min)at room temperature or even from a commodity plastic waste mixture under catalyst-free thermal bulk condition(180°C),thus establishing its circular life cycle.P(Me-DTO)could be applied for selective removal of Hg^(2+)with>99%removal efficiency.More importantly,Me-DTO could be recovered in high yield after utilization for Hg^(2+)adsorption.展开更多
Metal-organic polyhedra(MOPs)possess a microporous framework and impose hierarchical constraints on their surface ligands,leading to the long-ignored,logarithmic ligand exchange dynamics.Herein,polymer networks with M...Metal-organic polyhedra(MOPs)possess a microporous framework and impose hierarchical constraints on their surface ligands,leading to the long-ignored,logarithmic ligand exchange dynamics.Herein,polymer networks with MOP as nanoscale cross-linkers(MOP-CNs)can integrate unique ligand exchange dynamics and microporosity,affording vitrimer-like gas separation membranes with promising mechanical performance and(re)processability.All the ligands on the MOP surfaces are confined and correlated via a 3D coordination framework and their neighboring spaces,giving rise to a high energy barrier for ligand exchange.Therefore,MOP-CNs demonstrate high mechanical strengths at room temperature due to their negligible ligand dynamics.The thermo-activated ligand exchange process with integrated network topology enables facile(re)processing and high solvo-resistance at high temperatures.This facilitates Arrhenius type temperature dependence of flowability and stress relaxation,giving rise to the simultaneous achievement of promising mechanical strengths and(re)processability.Finally,the cage topologies of MOPs endow the materials with a bonus microporous feature and spur their applications as gas separation membranes.展开更多
The environmentally sustainable disposal and recycling of ever increasing volumes of electronic waste has become a global waste management issue. The addition of up to 25% polymeric waste PCBs （printed circuit boards...The environmentally sustainable disposal and recycling of ever increasing volumes of electronic waste has become a global waste management issue. The addition of up to 25% polymeric waste PCBs （printed circuit boards） as fillers in polypropylene （PP） composites was partially successful： while the tensile modulus, flexural strength and tlexural modulus of composites were enhanced, the tenstle and impact strengths were found to decrease. As a lowering of impact strength can significantly limit the application of PP based composites, it is necessary to incorporate impact modifying polymers such as rubbery particles in the mix. We report on a novel investigation on the simultaneous utilization of electronic and automotive rubber waste as fillers in PP composites. These composites were prepared by using 25 wt.% polymeric PCB powder, up to 9% of ethylene propylene rubber （EPR）, and PP： balance. The influence of EPR on the structural, thermal, mechanical and rheological properties of PP/PCB/ EPR composites was investigated. While the addition of EPR caused the nucleation of the I~ crystalline phase of PP, the onset temperature for thermal degradation was found to decrease by 8%. The tensile modulus and strength decreased by 1 b% and 19%, respectively; and the elongataon at break increased by -71%. The impact strength showed a maximum increase of-18% at 7 wt.%-9 wt.% EPR content. Various rheological properties were found to be well within the range of processing limits. This novel eco-friendly approach could help utilize significant amounts of polymeric electronic and automotive waste for fabricating valuable polymer composites.展开更多
基金supported by The National Natural Science Foundation of China(21504039)。
文摘Recyclable polymers offer a great opportunity to address the environmental issues of plastics.Herein,functionalization of recyclable polymers,poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),were reported via end-group modifications and block/random copolymerizations.Di-n-butylmagnesium was selected to catalyze ring-opening polymerization(ROP)of(R)-M in the presence of a series of functional alcohols as the initiators.Block/random copolymerizations of(R)-M andε-caprolactone(ε-CL),L-lactide(L-LA)and trimethylene carbonate(TMC)were performed to control the onset decomposition temperature(T_(d)),melting temperature(T_(m))and glass transition temperature(T_(g)).These functionalized recyclable polymers would find broad applications as the sustainable plastics.
基金supported by the National Natural Science Foundation of China(22225104,22071077 and 92356302)China Postdoctoral Science Foundation(2022TQ0115 and 2022M711297).
文摘The development of modern society is closely related to polymer materials.However,the improper disposal of the polymer wastes not only squanders resources but also intensifies the environmental issues,despite that energy recovery,physical recycling and chemical recycling pathways have been developed to tackle the recycle and reuse of polymers.Among them,chemical recycling is considered as the most pivotal solution,as it can depolymerize the polymer wastes back to monomers,which then repolymerize into polymer materials.Recently,remarkable progress has been made in the development of chemically recyclable polymers through monomer design to shift“polymerization-depolymerization”equilibrium to realize the selective depolymerization of the polymers into monomers,and to achieve chemical recycling closed-loop.This article reviews the closed-loop polymers such as polyesters,polycarbonates,sulfur-containing polymers,vinyl monomer-based polymers as well as other types of polymers.Moreover,the challenges and prospects in this field are also discussed.
基金supported by grants from the National Science Fund for Distinguished Young Scholars(22325108)National Natural Science Foundation of China(91856113,U21A2089 and 52273015)+2 种基金the National Key Research and Development Program of China(2022YFE0130500)the State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC,PR20232038)Jilin Province and CAS(2022SYHZ0034).
文摘Developing polymers that can be chemically recycled signifies a considerable prospect to polymer scientists to tackle the increasing plastic crises but is still plagued with certain limitations in architecture/performance diversity and depolymerization activity.Polythioesters synthesized through ring-opening polymerization(ROP)of cyclic thioesters monomers are captivating materials owing to the labile thioester bonds in polymer chains and the low ring strain energy of thiolactone monomers.In this brief review,the latest advancements in the ring-opening polymerization of dithiolactone and monothiodilactone monomers to prepare chemically recycled polythioesters are summarized.Moreover,the feasibility and challenges in future practical applications of chemically recyclable polythioesters derived from dithiolactone and monothiodilactone will be discussed.
基金the National Natural Science Foundation of China(Nos.92256301,22371085,22271113,22471089)the National Key R&D Program of China(Nos.2023YFA1507203,2024YFA1509700)+4 种基金the Fundamental Research Funds for the Central Universities(No.CCNU24JCPT018)the Wuhan Natural Science Foundation(No.2024040801020303)the Postdoctor Project of Hubei Province under Grant Number 2024HBBHCXB039the China Postdoctoral Science Foundation(No.2024M751614)First Batch of Postdoctoral Overseas Talent Program of China for support of this research.
文摘Chiral bisoxazoline(box)ligands with indene groups at C4 and C5 are highly potent in asymmetric catalysis,but face challenges in terms of cost and recyclability.To address this,we have designed polystyrene-supported box ligands by modifying the indene moiety instead of the traditional methylene bridge.This design preserves the necessary steric environment for copper coordination,enabling high efficiency and excellent enantioselectivity as examined in photoinduced asymmetric cyanation reactions.The resulting copper complexes are robust and recyclable,maintaining performance over five cycles.This approach provides a sustainable and practical solution for asymmetric catalysis with chiral box ligands.
基金supported by the National Natural Science Foundation of China(grant nos.21935004 and 22305093).
文摘The fabrication of liquid-free ionic conductive elastomers(ICEs)that can function as flexible temperature sensors with high sensitivity,fast response time,and efficient recyclability is a great challenge.In this study,novel liquid-free ICEs are conveniently fabricated through the complexation of 4-carboxybenzaldehyde-grafted poly(vinyl alcohol)(CPVA)with well-designed solid quaternary ammonium(QA)molecules bearing bifunctional hydrogen-bonding moieties.The resulting CPVA-QA elastomers,which are highly elastic and adhesive to diverse surfaces,exhibit a tensile strength of 6.6 MPa,a toughness of 14.7 MJ m^(-3),and a Young’s modulus of 0.15 MPa.These elastomers have a hydrogen-bonded network structure where the bifunctional QA molecules significantly suppress polymer chain entanglements.Benefitting from the thermally sensitive hydrogen bonds and the substantially reduced chain entanglements,the CPVA-QA elastomers show a high chain mobility upon temperature elevation,which facilitates ion transport within the CPVA-QA elastomers.Consequently,the CPVA-QA elastomer-based temperature sensors show an outstanding temperature resolution(0.05℃),a fast response time over a wide temperature range,and a record-high thermosensitivity of 10.8%K-1.Importantly,the CPVA-QA sensors can be depolymerized under mild conditions to recover their original components in high purity and yields(>96%),enabling closed-loop recycling of the sensors.
文摘PU （polyurethane） integral skin and PVC （polyvinyl chloride） are polymeric materials which have favorable physical characteristics to reduce the impact noise when applied to floor systems. In civil construction, floating floors systems are composed of two layers above the slab： a resilient layer and, above this, a rigid layer of cement matrix that works as a subfloor. This research aims to evaluate the incorporation of PVC and PU skin waste in the resilient layer of the floating floor, for impact noise insulation. It was conducted physical, mechanical and morphological tests in the composite, as SEM （scanning electron microscopy）, determination of compressive creep, and impact noise test to evaluate the absorption capacity of the floor system over time. Furthermore, experimental results were compared with theoretical studies. These correlations may assist in understanding the behavior of impact noise damping and its relation to the size of the samples.
文摘In this article, based on the analysis of the current environmental situation in Russia and other countries, as well as of the problem of recycling plastic waste in the Russian Federation （RF）, the authors clearly show the effectiveness of investments in the processing of polymer debris on the example of polyethylene terephthalate （PET） waste （granulates, flakes）. In the frame of case study of social and environmental investment project on creating enterprise that will engage in collection, recycling, and sale of the consumer PET packaging in Russia, the authors demonstrate the economic feasibility of the creation of such kind of enterprises taking into account market conditions and the features of the existing system of taxation in Russia. The realization of the project will also help in solving environmental and social problems of large cities, in particular, will create more jobs （in terms of 6% of unemployment rate in the country）. The study also identifies the main obstacles in the way of waste recycling in Russia, and the recommendations for improvement of normative base of the industry are given.
基金National Natural Science Foundation of China,Grant/Award Numbers:52237001,51921005。
文摘Polypropylene(PP)has become the focus of research and development of recyclable polymer dielectric materials because of its excellent electrical and thermal properties.The residual catalyst after PP polymerisation is the main part of ash.It was found that ash particles are uniformly dispersed in the PP matrix.The increase in ash content leads to a gradual decrease in their spacing,and leads to a significant decrease in electrical prop-erties,with a difference of more than one order of magnitude for volume resistivity.The decrease in the ion migration potential barrier caused by the increase of ash content is the key factor in deteriorating the electrical properties of PP.The effect of ash on the elec-trical properties of PP mainly lies in enhancing the migration of ion carriers.The PP volume resistivity corresponds to an ash threshold of 292 ppm,above which the con-centration leads to an increase in ion carriers.The accumulation of carriers leads to in-ternal electric field distortion enhancing the transition ability of carriers and leading to a rapid decrease in the electrical properties of PP.This study provides a feasible reference for the development of high-performance PP insulation materials for power cables and other applications.
基金support of the National Natural Science Foundation of China(grant nos.52373014,U23A2083,and 52203129).
文摘Researchers are pursuing promising chemically recyclable polymers.Here,we demonstrate a series of recyclable Se-containing polyesters from the first reported cascade multicomponent polymerization of elemental Se,H_(2)O,CO,and diacrylate.The polymerization is considered to be through a cascade mechanism:Se is first reduced by CO to COSe;COSe is then reduced by H_(2)O to H_(2)Se;H_(2)Se is finally coupled with diacrylate to form a polymer.The method uses common organic bases as a catalyst and is performed under mild conditions with high yields.The obtained polymer is thermally stable with a tunable melting point,and can be easily depolymerized to Se and diacrylate by H_(2)O_(2) under mild conditions.Owing to the versatile synthesis,the structure/properties of the polymer are scalable,such as P4 and P5 with high-density polyethylene-like mechanical performance.Overall,the polymer is a promising material owing to its modular synthesis,practical recyclability,scalable performance,and commercial raw materials.
基金supported by the National Natural Science Foundation of China (22241501, 92261117)the Guangdong-Hong Kong-Macao Joint Laboratory for Neutron Scattering Science and Technology+2 种基金the Open Fund of the China Spallation Neutron Source Songshan Lake Science City (DG24313519)the TCL Science and Technology Innovation FundGuangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices
文摘Mixed matrix membranes(MMMs)are designed by incorporating microporous inorganic fillers into polymer matrix for the integration of inorganics’excellent gas separation performance with polymers’promising flexibility.However,due to the complex interphase interaction,the prevention of long-term aging is still challenging and the poor processability/recyclability of MMMs hinders their extensive applications.Herein,a coordination assembly protocol is developed for the fabrication of MMMs with both excellent processability/recyclability upon thermal annealing and promising dimension stability even under high gas pressure.Polymers bearing isophthalic acid(IPA)as side chains are applied to coordinate with Cu^(2+)and the assembled 2.5 nm microporous metal-organic polyhedra(MOP),{Cu_(24)IPA_(24)},serves as multi-functional cross-linkers for the polymer network formation.The MOPs’well-defined microporosity grants MMMs the capability for O_(2)/N_(2) separation while their activated dynamics at high temperatures(>120℃)endows polymer networks with excellent processability.In contrast to conventional supramolecular units,the MOPs possess unique logarithmic ligand-exchange kinetics and they show nearly frozen bonding dynamics at room temperature,ensuring promising dimensional stability to overcome the long-term aging and high gas pressure effect.This work not only provides fundamental understanding of the unique relaxation dynamics of complex systems with intertwined dynamics of supramolecular bonds and polymer chains,but also paves new avenues for the fabrication of robust and recyclable MMMs and elastomers.
基金support by National Natural Science Foundation of China(Nos.52322304,22075160 and 22031005)Taishan Scholar Foundation of Shandong Province(No.tsqn202103078).
文摘Copolymerization as an efficient strategy can provide an opportunity to create new closed-loop recyclable polymeric materials with tailored properties that are generally inaccessible to the individual homopolymers.In this contribution,the bulk ring-opening copolymerization of bio-renewable-caprolactone and trans-hexahydro-(4,5)-benzofuranone was achieved to produce closed-loop recyclable copolyesters by using an organobase/urea binary catalyst at room temperature.The obtained copolyesters exhibited composition-dependent thermal properties.Remarkably,the obtained copolyesters were able to depolymerize back to recover the corresponding monomers under mild conditions.
基金supported by the National Natural Science Foundation of China(NSFC grant no.21935004).
文摘Traditional flame-retardant plastics are technically difficult to chemically recycle.The development of newtypes of flame-retardant plastics that are intrinsically capable of being closed-loop recycled and are sufficiently robust and stable to satisfy their practical application is urgently needed.In this study,closed-loop recyclable flame-retardant plastics with high mechanical strength and excellent chemical resistance are fabricated by cross-linking amino-terminated polyimide(PI-NH_(2))and aldehyde-terminated cyclophosphazene(CP-CHO)with imine bonds.The resultant flame-retardant plastic,which is denoted as PI-CP,exhibits a tensile strength of∼115.6 MPa,Young’s modulus of∼2.5 GPa,and glass transition temperature of 316°C.In the PI-CP plastic,the imine bonds are isolated within hydrophobic microenvironments generated by the rigid and hydrophobic polyimide chains and the benzene ring of cyclophosphazenes.As a result,the PI-CP plastics are highly stable in highly acidic and basic aqueous solutions and other commonly used organic solvents.The PI-CP plastic shows outstanding flame retardancy with a limiting oxygen index value of 48.8%.More importantly,the PI-CP plastic can be depolymerized to generate the original PI-NH_(2)and CPCHO monomers in high yields(∼97%)and purity.The recovered monomers can be used to refabricate the original plastics,establishing highly efficient polymer-monomer-polymer circulation and a sustainable plastics economy.
文摘The extensive use of plastics,valued for their lightweight,durability,and cost-effectiveness,has led to severe environmental pollution,with 72%of plastic waste ending up in landfills or natural habitats.Traditional methods for plastic decomposition,including both mechanical and chemical approaches,often face challenges such as incomplete degradation and stability concerns.The innovative concept of mechanical gating presents a promising solution by incorporating mechanophores into polymer structures,enabling controlled degradation.Recent advancements have focused on utilizing mechanophores,such as cyclobutane,as"door locks"to regulate the degradation process.This perspective highlights recent progress in this field,demonstrating the potential of mechanophore-based strategies for achieving on-demand polymer degradation.It addresses the limitations of conventional recycling methods and explores how this approach can balance polymer stability with environmental degradability,paving the way for more sustainable plastic management solutions.
基金National Natural Science Foundation of China(NSFC,21971230 and U19B6001)the mentorship and strong support from Professor Changle Chen(USTC).
文摘Comprehensive Summary Introducing covalently crosslinked network to telechelic polymers can enable the formation of advanced polymeric materials with enhanced material properties.In this contribution,well-defined telechelic polymers bearing acetoacetate groups were synthesized via Ru-catalyzed ring-opening metathesis polymerization of cyclooctene in the presence of chain transfer agents.Given the unique feature of muti-site reactive acetoacetate end groups,several crosslinked networks were constructed using different crosslinkers under mild conditions.In the Michael addition reaction system,the introduction of di/trifunctional aliphatic acrylate as crosslinkers significantly enhanced the mechanical properties of the generated crosslinked network(tensile strength up to 27 MPa,elongation at break up to 500%).On the other hand,vitrimers with dynamic covalent crosslinked networks were accessed via transamination of vinylogous urethane reaction using telechelic polymers and tris(2-aminoethyl)amine.
基金supported by the National Natural Science Foundation of China(21875208,51962036)Key Project of the Natural Science Foundation of Yunnan(Grant 202201AS070011)High-Level Talents Introduction in Yunnan Province(C619300A025).
文摘Comprehensive Summary,Although polyimides(PIs)have shown great potential for a broad range of applications,it remains very challenging to achieve the malleability,rehealability and recyclability for PIs and their composites targeting various applications,particularly for the rapidly emerging flexible and stretchable electronics.Herein,malleable conductive poly(imide-imine)hybrid(PIIH)vitrimer-graphene aerogel(GA)composites have been prepared,for the first time,via simple sol-gel film formation followed by heat-press.The resulting PIIH-GA composites exhibit not only the highly desired properties of thermosetting(strong mechanical strength)and thermoplastic(reprocessability)polymers,but also good conductivity enabled by the GA filler.PIIH3-GA-10(with 10 wt%GA)showed one of the highest electrical conductivities(26.7 S/m)for PI-based composites,as well as good electromagnetic interference(EMI)shielding performance.Moreover,the PIIH-GA films could maintain good performance during stretching and even after chemical recycling,which opens new opportunities for flexible and sustainable electronics development.
基金support by the National Natural Science Foundation of China(21901249)the Taishan Scholars Program of Shandong Province(tsqn201812112)the Scientific Research and Innovation Fund Project of the Shandong Energy Research Institute(SEI I202004).
文摘Plastics are integral to numerous significant social advancements.Nonetheless,their contribution to environmental pollution and climate crises cannot be disregarded,as their negative impact on the environment increases with incremental production capacity and demand.Concerted global action is urgently required to promote the green recycle of plastics to prevent their accumulation in the environment and mitigate carbon emissions.This review aims to reveal the paths of green development for polyester plastics,incorporating the trends of the green revolution in mature commercial polyester plastics,newly emerging biodegradable polyester plastics,and future polyester plastics.A critical discussion was conducted on the current and potential future research areas from multiple perspectives,including raw materials,processes,and recycling,to propel us into a future marked by sustainability.
基金supported by the National Key R&D Program of China(2021YFA1501700)the National Natural Science Foundation of China(51903177,U19A2095)+1 种基金the“1000-Youth Talents Program”the Fundamental Research Funds for the Central Universities(YJ201924,YJ202209)。
文摘Developing new chemically recyclable polymers is important for a circular plastics economy.Herein,we prepared a class of 1,4-dithian-2-one(DTO)with thioether and thioester functionalities.These sulfur-substituted monomers(DTO)showed excellent reactivity for ring-opening polymerization(turnover frequency(TOF)up to 2.3×10^(4)h^(-1)),which afforded poly(thioetherthioester)s(P(DTO)s)with high air stability,high crystallinity,and commercial high-density polyethylene-like mechanical property(σB=29.59±1.08 MPa andεB=749%±36%).Intriguingly,chemical recycling of P(DTO)to monomer could be accomplished with excellent efficiency in dilute solution(1 min)at room temperature or even from a commodity plastic waste mixture under catalyst-free thermal bulk condition(180°C),thus establishing its circular life cycle.P(Me-DTO)could be applied for selective removal of Hg^(2+)with>99%removal efficiency.More importantly,Me-DTO could be recovered in high yield after utilization for Hg^(2+)adsorption.
基金The work is supported by the National Natural Science Foundation of China(grant nos.51873067 and 21961142018)the Natural Science Foundation of Guangdong Province(grant no.2021A1515012024).
文摘Metal-organic polyhedra(MOPs)possess a microporous framework and impose hierarchical constraints on their surface ligands,leading to the long-ignored,logarithmic ligand exchange dynamics.Herein,polymer networks with MOP as nanoscale cross-linkers(MOP-CNs)can integrate unique ligand exchange dynamics and microporosity,affording vitrimer-like gas separation membranes with promising mechanical performance and(re)processability.All the ligands on the MOP surfaces are confined and correlated via a 3D coordination framework and their neighboring spaces,giving rise to a high energy barrier for ligand exchange.Therefore,MOP-CNs demonstrate high mechanical strengths at room temperature due to their negligible ligand dynamics.The thermo-activated ligand exchange process with integrated network topology enables facile(re)processing and high solvo-resistance at high temperatures.This facilitates Arrhenius type temperature dependence of flowability and stress relaxation,giving rise to the simultaneous achievement of promising mechanical strengths and(re)processability.Finally,the cage topologies of MOPs endow the materials with a bonus microporous feature and spur their applications as gas separation membranes.
文摘The environmentally sustainable disposal and recycling of ever increasing volumes of electronic waste has become a global waste management issue. The addition of up to 25% polymeric waste PCBs （printed circuit boards） as fillers in polypropylene （PP） composites was partially successful： while the tensile modulus, flexural strength and tlexural modulus of composites were enhanced, the tenstle and impact strengths were found to decrease. As a lowering of impact strength can significantly limit the application of PP based composites, it is necessary to incorporate impact modifying polymers such as rubbery particles in the mix. We report on a novel investigation on the simultaneous utilization of electronic and automotive rubber waste as fillers in PP composites. These composites were prepared by using 25 wt.% polymeric PCB powder, up to 9% of ethylene propylene rubber （EPR）, and PP： balance. The influence of EPR on the structural, thermal, mechanical and rheological properties of PP/PCB/ EPR composites was investigated. While the addition of EPR caused the nucleation of the I~ crystalline phase of PP, the onset temperature for thermal degradation was found to decrease by 8%. The tensile modulus and strength decreased by 1 b% and 19%, respectively; and the elongataon at break increased by -71%. The impact strength showed a maximum increase of-18% at 7 wt.%-9 wt.% EPR content. Various rheological properties were found to be well within the range of processing limits. This novel eco-friendly approach could help utilize significant amounts of polymeric electronic and automotive waste for fabricating valuable polymer composites.
