Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability propertie...Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability properties.It is well known that PBAT suffers a series of natural weathering,mechanical wear,hydrolysis,photochemical transformation,and other abiotic degradation processes before being biodegraded.Therefore,it is particularly important to understand the role of abiotic degradation in the life cycle of PBAT.Since the abiotic degradation of PBAT has not been systematically summarized,this review aims to summarize the mechanisms and main factors of the three major abiotic degradation pathways(hydrolysis,photochemical transformation,and thermochemical degradation)of PBAT.It was found that all of them preferentially destroy the chemical bonds with higher energy(especially C-O and C=O)of PBAT,which eventually leads to the shortening of the polymer chain and then leads to reduction in molecular weight.The main factors affecting these abiotic degradations are closely related to the energy or PBAT structure.These findings provide important theoretical and practical guidance for identifying effective methods for PBAT waste management and proposing advanced schemes to regulate the degradation rate of PBAT.展开更多
Chain-growth radical polymerization of vinyl monomers is essential for producing a wide range of materials with properties tailored to specific applications.However,the inherent resistance of the polymer's C―C ba...Chain-growth radical polymerization of vinyl monomers is essential for producing a wide range of materials with properties tailored to specific applications.However,the inherent resistance of the polymer's C―C backbone to degradation raises significant concerns regarding long-term environmental persistence,which also limits their potential in biomedical applications.To address these challenges,researchers have developed strategies to either degrade preexisting vinyl polymers or incorporate cleavable units into the backbone to modify them with enhanced degradability.This review explores the various approaches aimed at achieving backbone degradability in chain-growth radical polymerization of vinyl monomers,while also highlighting future research directions for the development of application-driven degradable vinyl polymers.展开更多
Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermo...Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermoplastic and thermoset plastics,the development of high-performance degradable polymer adhesives is rare.Here,we have prepared high-performance nucleobase-containing thioctic acid-based supramolecular polymer adhesives through free radical polymerization.The specific hydrogen-bonding interactions between complementary nucleobases greatly improve the weak cohesion of the thioctic acid-based polymers and enhance the environmental stability of the thioctic acidbased polymers simultaneously.Degradation of the nucleobase-containing thioctic acid-based supramolecular polymers is achieved by the reduction of the disulfide backbone,and the cycle of degradation and repolymerization is further achieved via oxidative polymerization.The adhesion strength of the nucleobase-containing thioctic acid-based supramolecular polymers after two cycles of degradation and repolymerization still reaches as high as 4.7±0.3 MPa.This work provides an approach for the development of environmentally stable and high-performance degradable thioctic acid-based adhesives.展开更多
Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymeriza...Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymerization of o-phthalaldehyde(OPA)and epoxide using Lewis pair type two-component organocatalysts for producing acetal-functionalized polyether and polyurethane.Notably,triethylborane as the Lewis acid,in comparison with tri(n-butyl)borane,more effectively enhances the polymerization activity by mitigating borane-induced reduction of the aldehyde group into extra initiating(borinic ester)species.Density functional theory(DFT)calculations present comparable energy barriers of OPA-epoxide cross-propagation and epoxide self-propagation,which is consistent with the experimental finding that an alternating-rich copolymer comprising mostly OPA-epoxide units but also epoxide-epoxide linkages is produced.In particular,when epoxide is added in a large excess,the product becomes a polyether containing acetal functionalities in the central part of the backbone and thus being convertible into polyurethane with refined acid degradability.展开更多
The development of degradable and chemically recyclable polymers is a promising strategy to address pressing environmental and resource-related challenges.Despite significant progress,there is a need for continuous de...The development of degradable and chemically recyclable polymers is a promising strategy to address pressing environmental and resource-related challenges.Despite significant progress,there is a need for continuous development of such recyclable polymers.Herein,PPDOPLLA-PU copolymers were synthesized from poly(p-dioxanone)-diol(PPDO-diol)and poly(L-lactide)-diol(PLLA-diol)by chain extension reaction.The chemical structures and microphase structures of PPDO-PLLA-PU were characterized,and their crystalline properties,mechanical properties,and degradation behaviors were further investigated.Significantly,the distribution of PLLA phase in the copolymer matrix showed a rod-like microstructure with a slight orientation,despite the thermodynamic incompatibility of PPDO and PLLA segments.Moreover,on the basis of this microphase separation,PPDO spherulites can crystallize using the interface of the two phases as nucleation sites.Accordingly,the combined effect of above two contributes to the enhanced mechanical properties.In addition,PPDO-PLLA-PU copolymers have good processability and recyclability,making them valuable for a wide range of applications.展开更多
As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of t...As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of the novel imine-based polymer through the copolymerization of cyclooctene with cyclic imine comonomer via ROMP.Because of the efficient hydrolysis reactions of the imine group,the generated copolymer can be easily degraded under mild condition.Moreover,the generated degradable product was the telechelic polymer bearing amine group,which was highly challenged for its direct synthesis.And this telechelic polymer could also be used for the further synthesis of new polymer through post-transformation.The introduction of imine unit in this work provides a new example of the degradable polymer synthesis.展开更多
Traditional packaging plastics derived from fossil fuels for perishable foods have caused severe environmental pollution and resource depletion.To promote sustainable development and reduce wastage of perishable produ...Traditional packaging plastics derived from fossil fuels for perishable foods have caused severe environmental pollution and resource depletion.To promote sustainable development and reduce wastage of perishable products,there is a significant challenge in developing biobased packaging plastics that offer excellent preservation,satisfactory mechanical performance,and inherent degradability.In this study,poly(urethane-urea)(PUU)plastics are fabricated using a one-pot polyaddition reaction involving castor oil(CO),tannic acid(TA),lysine-derived ethyl 2,6-diisocyanatohexanoate(LDI),and H2O.The resulting PUU plastics demonstrate a high breaking strength of about 32.7 MPa and a strain at break of ca.102%.Due to the reversibility of hydrogen bonds,PUU plastics can be easily shaped into various forms.They are non-cytotoxic and suitable for food packaging.With a high TA content of ca.38.2 wt%,PUU plastics exhibit excellent antioxidant capacity.Consequently,PUU plastics show outstanding freshness preservation performance,extending the shelf life of cherry tomatoes and winter jujubes for at least 8 days at room temperature.Importantly,PUU plastics can autonomously degrade into non-toxic substances within ca.298 days when buried in soil.展开更多
In recent years,the biodegradable plastics has extensively used in industry,agriculture,and daily life.Herein,the effects of two biodegradable microplastics(BMPs),poly(butyleneadipate-co-terephthalate)(PBAT)and polyhy...In recent years,the biodegradable plastics has extensively used in industry,agriculture,and daily life.Herein,the effects of two biodegradable microplastics(BMPs),poly(butyleneadipate-co-terephthalate)(PBAT)and polyhydroxyalkanoate(PHA),on soil sulfamethoxazole(SMX)degradation and sul genes development were comparatively studied based on the type,dosage,and state.The addition of virgin BMPs significantly increased soil DOC following a sequential order PBAT>PHA and high dose>low dose.Meanwhile virgin PBAT significantly reduced soil pH.In general,the addition of BMPs not only promoted soil SMX degradation but also increased the abundance of sul genes,with an exception that pH reduction in virgin PBAT inhibited the proliferation of sul genes.The driving effects of BMPs on soil microbial diversity following the same order as that on DOC.Specific bacteria stimulated by BMPs,such as Arthrobacter and two genera affiliated with phylum TM7,accounted for the accelerated degradation of SMX.Intriguingly,UV-aging hindered the release of DOC from BMPs and the reduction in pH,mitigated the stimulation of microbial communities,and ultimately reduced the promotion effect of BMPs on SMX degradation and sul genes proliferation.Our results suggest that more attention should be paid to the proliferation risk of ARGs in the environment affected by BMPs and UV-aging can be employed sometimes to reduce this risk.展开更多
Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents ca...Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.展开更多
Mg and its alloys show high potential to be applied as implant materials due to their superior properties like biodegradability,bioactivity,biocompatibility,and suitable mechanical behaviors.Nevertheless,the fast and ...Mg and its alloys show high potential to be applied as implant materials due to their superior properties like biodegradability,bioactivity,biocompatibility,and suitable mechanical behaviors.Nevertheless,the fast and uncontrolled degradation of Mg alloys in biological environment severely restricts their wide applications as biomedical materials.In comparison with alloying,surface coatings can not only improve corrosion resistance but also impart other bio-functional properties to achieve diverse clinical requirements.This review analyzes and summarizes the most recent developments in popular coating technologies,including micro-arc oxidation,electrophoretic deposition,chemical conversion,anodic oxidation,layered double hydroxide,and sol-gel coatings.Considering inevitable damages under complex service conditions,smart self-healing coatings are also introduced in each coating technology.The existing issues and future perspectives are finally discussed to facilitate applications of Mg alloys as biomedical materials in the medical industry.展开更多
Incorporating a low density of ester units into the backbone of polyethylene materials enhances their sustainability and recyclability while maintaining the main material properties of polyethylenes.Here we report a n...Incorporating a low density of ester units into the backbone of polyethylene materials enhances their sustainability and recyclability while maintaining the main material properties of polyethylenes.Here we report a new way to access degradable polyethylene materials with a low content of in-chain ester units via mechanochemical backbone editing.Initially,ester groups are incorporated as side groups through catalytic copolymerization of ethylene with a cyclobutene-fused lactone monomer(CBL),yielding polyethylene materials with high molecular weights and adjustable thermomechanical properties.Subsequent solid-state ball-milling treatment selectively introduces side-chain ester groups into the main chain of the polyethylene materials via force-induced cycloreversion of the cyclobutane units.Under acidic conditions,hydrolysis of the resultant polyethylene materials with in-chain ester units facilitates further degradation into oligomers.展开更多
The increasing interest in Mg-Zn binary alloys as temporary implant materials is attributed to their outstanding biocompatibility,biodegradability,and favourable mechanical properties.However,their application is cons...The increasing interest in Mg-Zn binary alloys as temporary implant materials is attributed to their outstanding biocompatibility,biodegradability,and favourable mechanical properties.However,their application is constrained by high degradation rates in the physiological environment,resulting in the release of hydrogen gas and a rapid decline in mechanical properties.Additionally,the material's biocompatibility is contingent upon its degradability.Researchers have demonstrated that addressing these issues is possible through strategies such as controlling Zn content,employing thermo-mechanical processing to achieve suitable microstructures,and applying surface coatings.This manuscript provides a comprehensive review of published literature on Mg-Zn alloys,exploring the challenges and outlining future research directions in this field.展开更多
Poly(lactic acid)(PLA)is a biodegradable and eco-friendly polymer that is increasingly being incorporated into various applications in contemporary society.However,the limited stability of PLA-based products remains a...Poly(lactic acid)(PLA)is a biodegradable and eco-friendly polymer that is increasingly being incorporated into various applications in contemporary society.However,the limited stability of PLA-based products remains a significant challenge for their broader use in various applications.In this study,poly(L-lactic acid)(PLLA)/poly(D-lactic acid)(PDLA)melt-blown nonwovens were prepared by melt spinning.The structure,thermal properties,thermal stability,biodegradability and crystalline morphology of the melt-blown nonwovens were investigated.DSC and WAXD confirmed the formation of stereocomplex(SC)crystallites in the PLLA matrix.The storage modulus(G′),loss modulus(G″),and complex viscosity(∣η^(*)∣)of the PLLA/PDLA blend increased with an increase in SC crystallite content.The thermal degradation temperatures of PLLA/PDLA melt-blown nonwovens increased with the incorporation of SC crystallites,and the maximum rate of decomposition increased to 385.5℃,thus enhancing the thermal stability.Compared with neat PLLA melt-blown nonwovens,the hydrophobicity of PLLA/PDLA melt-blown nonwovens was improved,and WCA increased to 139.7°.The SC crystallites were more resistant to degradation by proteinase K compared to neat PLLA.However,the degradation rate of PLLA/PDLA melt-blown nonwovens remained at a high level.This work provides an effective strategy to obtain high-performance PLLA melt-blown nonwovens.展开更多
A study of the effect of rotary swaging(RS)at 350℃ on mechanical properties,corrosion resistance and biocompatibility in vitro and in vivo of biodegradable Mg-1%Zn-0.6%Ca alloy was conducted.It is shown that the form...A study of the effect of rotary swaging(RS)at 350℃ on mechanical properties,corrosion resistance and biocompatibility in vitro and in vivo of biodegradable Mg-1%Zn-0.6%Ca alloy was conducted.It is shown that the formation of a recrystallized microstructure after RS with a grain size of 3.2±0.2μm leads to an increase in the strength of the alloy without reduction of level of ductility and corrosion resistance.At the same time,aging of the quenched alloy at 100℃ for 8 h leads to a slight increase in strength,but significantly reduces its ductility and corrosion resistance.The study of the degradation process of the alloy in the quenched state and after RS,both under in vitro and in vivo conditions,did not reveal a significant difference between these two microstructural states.However,an increase in the duration of incubation of the alloy in a complete growth medium from 4 h to 24 days leads to a decrease in the degradation rate(DR)by 4times(from~2 to~0.5 mm/year)due to the formation of a dense layer of degradation products.The study of biocompatibility in vitro did not reveal a significant effect of RS on the hemolytic and cytotoxic activity of the alloy.No signs of systemic toxicity were observed after subcutaneous implantation of alloy samples into mice before and after RS.However,it was found that RS promotes uniform degradation of the alloy over the entire contact surface.In summary,RS at 350℃ allows to increase the strength of Mg-1%Zn-0.6%Ca alloy up to348±5 MPa at a ductility level of 17.3±2.8%and a DRin vivoequal to 0.56±0.12 mm/year without impairing its biocompatibility in vitro and in vivo.展开更多
Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polyme...Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polymers has become an attractive subject.Herein,a new monomer of thiosalicylic methyl glycolide(TSMG)was synthesized using one-pot method and high molecular weight poly(thiosalicylic methyl glycolide)(PTSMG,M_(n) up to 300 kDa)can be obtained via the ring-opening polymerization(ROP)of TSMG.PTSMG exhibits good closed-loop recyclability and hydrolytic degradability,where PTSMG can generate pristine monomers through sublimation thermal depolymerization conditions due to the presence of thiophenol ester bond in the polymer chains,and can be degraded rapidly in aqueous solution,which provides a potential solution to the current plastic pollution problem.展开更多
Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second sur...Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second surgery and have achieved clinical applications in orthopedic and cardiovascular fields.Porous scaffolds can provide functions such as bone integration and adjustable mechanical properties,thus widely used for bone repair.Additive manufacturing(AM)offers the advantages of design freedom and high precision,enabling the reliable production of porous scaffolds with customized structures.The combination of biodegradable Mg alloys,porous scaffolds,and AM processes has created tremendous opportunities for the precision treatment of bone defects.This article reviews the current development in the additive manufacturing process and design of Mg alloy biodegradable orthopedic implants,fo-cusing on chemical compositions,structural design,surface treatment,and their effects on mechanical properties,degradation behavior,and biocompatibility.Finally,the future perspective of porous Mg alloy biodegradable orthopedic implants is proposed.展开更多
Polyethyleneimine(PEI),as a widely used polymer material in the field of gene delivery,has been extensively studied for modification and shielding to reduce its cytotoxicity.However,research aimed at preparing degrada...Polyethyleneimine(PEI),as a widely used polymer material in the field of gene delivery,has been extensively studied for modification and shielding to reduce its cytotoxicity.However,research aimed at preparing degradable PEI is scarce.In this work,the hydrogen peroxide(H_(2)O_(2))oxidation method was used to introduce degradable amide groups in the PEI and a series of oxidized PEI22k(oxPEI22k)with different degrees of oxidation were synthesized by regulating the dosage of H_(2)O_(2).The relationship between the oxidation degree of oxPEI22k and the gene transfection efficiency of oxPEI22k was studied in detail,confirming that the oxPEI22k with oxidation degrees of 16.7%and 28.6%achieved improved transfection efficiency compared to unmodified PEI.These oxPEI22k also proved reduced cytotoxicity and improved degradability.Further,this strategy was extended to the synthesis of low-molecular-weight oxPEI1.8k.The oxPEI1.8k with suitable oxidation degree also achieved improved transfection efficiency and reduced cytotoxicity.In brief,this work provided high-efficiency and low-cytotoxicity degradable gene delivery carriers by regulating the oxidation degree of PEI,which was of great significance for promoting clinical applications of PEI.展开更多
The construction of enzyme reactors based on metal-organic frameworks(MOFs)as the immobilized matrix is a proven strategy that has achieved the widespread application of enzymes across industries.Although many MOFs an...The construction of enzyme reactors based on metal-organic frameworks(MOFs)as the immobilized matrix is a proven strategy that has achieved the widespread application of enzymes across industries.Although many MOFs and a variety of strategies have been developed,a formidable challenge remains in maintaining the high enzyme activity with excellent recyclability and tolerance for harsh conditions.Herein,using degradable redox stimuli-responsive liposomes as the templates with microporous MOFs(M-MOFs)as the hosts for enzyme encapsulation,a series of enzyme reactors(enzyme@M-MOFs)was designed and created.Based on the premise of enhancing enzyme protection in the harsh environment,this strategy provided a high degree-of-freedom space via removal of liposomes that improved the conformational freedom of the enzymes,promoted the mass transfer of substrates and products,and greatly boosted the catalytic activity.Importantly,the strategy had good universality and was applied to various liposomes,M-MOFs and enzymes.Additionally,the co-encapsulation of different enzymes with synergistic functions was performed using the M-MOFs platform.This study solved the problems of the conformation limitation of enzymes and mass transfer resistance of substrates and products using the proposed enzyme@M-MOFs,providing a new approach for the construction of biological cascade reaction devices based on MOFs materials.展开更多
Introducing covalently crosslinked network to polymer matrix can merge the advantages in reprocessing and durability of polymers.In this contribution,a series of high-performance vitrimeric elastomers were achieved vi...Introducing covalently crosslinked network to polymer matrix can merge the advantages in reprocessing and durability of polymers.In this contribution,a series of high-performance vitrimeric elastomers were achieved via polycondensation.The topological structures of polymers were tuned by varying the feeding ratios of bisacetoacetate,hex–substituted bisacetoacetate,bisamine and tris(2-aminoethyl)amine.With these structural manipulations,the vitrimeric elastomers presented great elastic recovery properties(strain recovery value up to 80%)benefiting from the introduction of long chain branch.Furthermore,the elastomers exhibited excellent reprocessing property,water vapor/oxygen barrier and adhesive properties.Specially,the elastomers could be degraded into monomer under acid conditions which enabled the elastomer synthesis again in closed loop recycling system.The ease of the polycondensation in this work to prepare highly elastic and recyclable vitrimeric elastomers demonstrated exciting opportunities for the synthesis of sustainable polymers.展开更多
Biodegradable magnesium alloys have been widely used in medical implants. But safety concerns were put forward for the high degradation rate of biodegradable magnesium alloy. The optimal biodegradable magnesium alloys...Biodegradable magnesium alloys have been widely used in medical implants. But safety concerns were put forward for the high degradation rate of biodegradable magnesium alloy. The optimal biodegradable magnesium alloys that give rise to the desired degradation rate hasn’t yet to be defined. Assessing the degradation rate of biodegradable magnesium alloys involves in vitro testing, in vivo testing, numerical modeling, understanding the factors influencing their degradation in physiological environments, biocompatibility testing, and clinical studies. It is important to standardize analytical tools aimed at assessing the degradation rate of biodegradable magnesium alloys. It is advisable to identify the threshold for safe degradation rate of biodegradable magnesium alloys in biomedical applications.展开更多
基金supported by the National Key R&D Program of China(No.2022YFC3901800)the National Natural Science Foundation of China(No.22176041)Guangzhou Science and Technology Planning Project(No.2023A04J0918)。
文摘Poly(butylene adipate-terephthalate)(PBAT),as one of the most common and promising biodegradable plastics,has been widely used in agriculture,packaging,and other industries due to its strong biodegradability properties.It is well known that PBAT suffers a series of natural weathering,mechanical wear,hydrolysis,photochemical transformation,and other abiotic degradation processes before being biodegraded.Therefore,it is particularly important to understand the role of abiotic degradation in the life cycle of PBAT.Since the abiotic degradation of PBAT has not been systematically summarized,this review aims to summarize the mechanisms and main factors of the three major abiotic degradation pathways(hydrolysis,photochemical transformation,and thermochemical degradation)of PBAT.It was found that all of them preferentially destroy the chemical bonds with higher energy(especially C-O and C=O)of PBAT,which eventually leads to the shortening of the polymer chain and then leads to reduction in molecular weight.The main factors affecting these abiotic degradations are closely related to the energy or PBAT structure.These findings provide important theoretical and practical guidance for identifying effective methods for PBAT waste management and proposing advanced schemes to regulate the degradation rate of PBAT.
基金funding from the National Natural Science Foundation of China(No.22401037)funding from JST CREST(No.JPMJCR23L1)。
文摘Chain-growth radical polymerization of vinyl monomers is essential for producing a wide range of materials with properties tailored to specific applications.However,the inherent resistance of the polymer's C―C backbone to degradation raises significant concerns regarding long-term environmental persistence,which also limits their potential in biomedical applications.To address these challenges,researchers have developed strategies to either degrade preexisting vinyl polymers or incorporate cleavable units into the backbone to modify them with enhanced degradability.This review explores the various approaches aimed at achieving backbone degradability in chain-growth radical polymerization of vinyl monomers,while also highlighting future research directions for the development of application-driven degradable vinyl polymers.
基金supported by the National Natural Science Foundation of China(Nos.22273098,22373003,22103002 and 52033001)the Key Project of Anhui Province Science and Technology Innovation Platform(No.202305a12020030)the financial support from the Anhui Provincial Natural Science Foundation(No.2408085Y004)。
文摘Polymeric materials which can undergo controlled degradation and recycling are of great significance for a sustainable society.Although tremendous progress has been made in the degradation and recycling of both thermoplastic and thermoset plastics,the development of high-performance degradable polymer adhesives is rare.Here,we have prepared high-performance nucleobase-containing thioctic acid-based supramolecular polymer adhesives through free radical polymerization.The specific hydrogen-bonding interactions between complementary nucleobases greatly improve the weak cohesion of the thioctic acid-based polymers and enhance the environmental stability of the thioctic acidbased polymers simultaneously.Degradation of the nucleobase-containing thioctic acid-based supramolecular polymers is achieved by the reduction of the disulfide backbone,and the cycle of degradation and repolymerization is further achieved via oxidative polymerization.The adhesion strength of the nucleobase-containing thioctic acid-based supramolecular polymers after two cycles of degradation and repolymerization still reaches as high as 4.7±0.3 MPa.This work provides an approach for the development of environmentally stable and high-performance degradable thioctic acid-based adhesives.
基金financially supported by the National Key R&D Program of China(No.2022YFC2805103)the National Natural Science Foundation of China(Nos.52022031 and 52263001)the Foundation from Qinghai Science and Technology Department(No.2022-ZJ-944Q)。
文摘Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymerization of o-phthalaldehyde(OPA)and epoxide using Lewis pair type two-component organocatalysts for producing acetal-functionalized polyether and polyurethane.Notably,triethylborane as the Lewis acid,in comparison with tri(n-butyl)borane,more effectively enhances the polymerization activity by mitigating borane-induced reduction of the aldehyde group into extra initiating(borinic ester)species.Density functional theory(DFT)calculations present comparable energy barriers of OPA-epoxide cross-propagation and epoxide self-propagation,which is consistent with the experimental finding that an alternating-rich copolymer comprising mostly OPA-epoxide units but also epoxide-epoxide linkages is produced.In particular,when epoxide is added in a large excess,the product becomes a polyether containing acetal functionalities in the central part of the backbone and thus being convertible into polyurethane with refined acid degradability.
基金financially supported by the National Key R&D Program of China(No.2021YFB3801901)the National Natural Science Foundation of China(Nos.52403138 and U19A2095)+1 种基金Institutional Research Fund from Sichuan University(No.2020SCUNL205)Fundamental Research Funds for the Central Universities,and 111 Project(No.B20001)。
文摘The development of degradable and chemically recyclable polymers is a promising strategy to address pressing environmental and resource-related challenges.Despite significant progress,there is a need for continuous development of such recyclable polymers.Herein,PPDOPLLA-PU copolymers were synthesized from poly(p-dioxanone)-diol(PPDO-diol)and poly(L-lactide)-diol(PLLA-diol)by chain extension reaction.The chemical structures and microphase structures of PPDO-PLLA-PU were characterized,and their crystalline properties,mechanical properties,and degradation behaviors were further investigated.Significantly,the distribution of PLLA phase in the copolymer matrix showed a rod-like microstructure with a slight orientation,despite the thermodynamic incompatibility of PPDO and PLLA segments.Moreover,on the basis of this microphase separation,PPDO spherulites can crystallize using the interface of the two phases as nucleation sites.Accordingly,the combined effect of above two contributes to the enhanced mechanical properties.In addition,PPDO-PLLA-PU copolymers have good processability and recyclability,making them valuable for a wide range of applications.
基金financially supported by National Key R&D Program of China(No.2021YFA1501700)CAS Project for Young Scientists in Basic Research(No.YSBR-094)+1 种基金Natural Science Foundation of Anhui Province(Nos.2308085Y35 and 2023AH030002)Hefei Natural Science Foundation(No.202304)。
文摘As a powerful synthetic tool,ruthenium-catalyzed ring-opening metathesis polymerization(ROMP)has been widely utilized to prepare diverse heteroatom-containing polymers.In this contribution,we report the synthesis of the novel imine-based polymer through the copolymerization of cyclooctene with cyclic imine comonomer via ROMP.Because of the efficient hydrolysis reactions of the imine group,the generated copolymer can be easily degraded under mild condition.Moreover,the generated degradable product was the telechelic polymer bearing amine group,which was highly challenged for its direct synthesis.And this telechelic polymer could also be used for the further synthesis of new polymer through post-transformation.The introduction of imine unit in this work provides a new example of the degradable polymer synthesis.
基金supported by the National Natural Science Foundation of China(Nos.21935004 and 22350011)。
文摘Traditional packaging plastics derived from fossil fuels for perishable foods have caused severe environmental pollution and resource depletion.To promote sustainable development and reduce wastage of perishable products,there is a significant challenge in developing biobased packaging plastics that offer excellent preservation,satisfactory mechanical performance,and inherent degradability.In this study,poly(urethane-urea)(PUU)plastics are fabricated using a one-pot polyaddition reaction involving castor oil(CO),tannic acid(TA),lysine-derived ethyl 2,6-diisocyanatohexanoate(LDI),and H2O.The resulting PUU plastics demonstrate a high breaking strength of about 32.7 MPa and a strain at break of ca.102%.Due to the reversibility of hydrogen bonds,PUU plastics can be easily shaped into various forms.They are non-cytotoxic and suitable for food packaging.With a high TA content of ca.38.2 wt%,PUU plastics exhibit excellent antioxidant capacity.Consequently,PUU plastics show outstanding freshness preservation performance,extending the shelf life of cherry tomatoes and winter jujubes for at least 8 days at room temperature.Importantly,PUU plastics can autonomously degrade into non-toxic substances within ca.298 days when buried in soil.
基金supported by the National Key Plan for Research and Development of China(Nos.2022YFE0120300 and 2020YFC1806902)the National Natural Science Foundation of China(Nos.42161134002,81991535,and 41877058)the Natural Science Foundation of Fujian Province,China(No.2022J01509).
文摘In recent years,the biodegradable plastics has extensively used in industry,agriculture,and daily life.Herein,the effects of two biodegradable microplastics(BMPs),poly(butyleneadipate-co-terephthalate)(PBAT)and polyhydroxyalkanoate(PHA),on soil sulfamethoxazole(SMX)degradation and sul genes development were comparatively studied based on the type,dosage,and state.The addition of virgin BMPs significantly increased soil DOC following a sequential order PBAT>PHA and high dose>low dose.Meanwhile virgin PBAT significantly reduced soil pH.In general,the addition of BMPs not only promoted soil SMX degradation but also increased the abundance of sul genes,with an exception that pH reduction in virgin PBAT inhibited the proliferation of sul genes.The driving effects of BMPs on soil microbial diversity following the same order as that on DOC.Specific bacteria stimulated by BMPs,such as Arthrobacter and two genera affiliated with phylum TM7,accounted for the accelerated degradation of SMX.Intriguingly,UV-aging hindered the release of DOC from BMPs and the reduction in pH,mitigated the stimulation of microbial communities,and ultimately reduced the promotion effect of BMPs on SMX degradation and sul genes proliferation.Our results suggest that more attention should be paid to the proliferation risk of ARGs in the environment affected by BMPs and UV-aging can be employed sometimes to reduce this risk.
基金supported by Natural Science Foundation of Hunan Province(2021JJ31081,2024JJ5619)the Science Fund of State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle(No 32215004).
文摘Biliary system,which is responsible for transporting bile from the liver into the intestine,is commonly damaged by inflammation or tumors eventually causing liver failure or death.The implantation of biliary stents can effectively alleviate both benign and malignant biliary strictures,but the plastic and metal stents that are currently used cannot degrade and nearly has no beneficial biological effects,therefore their long-term service can result into inflammation,the formation of sludges and re-obstruction of bile duct.In recent years,magnesium(Mg)metal has been received increasing attention in the field of biomedical application due to its excellent biocompatibility,adequate mechanical properties,biodegradability and other advantages,such as anti-inflammatory and anti-tumor properties.The research on biliary stents made of magnesium metals(BSMM)has also made significant progress and a series of experiments in vitro and vivo has proved their possibility.However,there are still some problems holding back BSMM’s clinical use,including rapid corrosion rate and potential harmful reaction.In this review,we would summarize the current research of BSMM,evaluate their clinical benefits,find the choke points,and discuss the solving method.
基金supported by the Chongqing Natural Science Foundation(No.CSTB2023NSCQ-MSX0512)Municipal Human Resources and Social Security Bureau(No.cx2022098)China Postdoctoral Science Foundation(Nos.2022T150767 and 2021M693708).
文摘Mg and its alloys show high potential to be applied as implant materials due to their superior properties like biodegradability,bioactivity,biocompatibility,and suitable mechanical behaviors.Nevertheless,the fast and uncontrolled degradation of Mg alloys in biological environment severely restricts their wide applications as biomedical materials.In comparison with alloying,surface coatings can not only improve corrosion resistance but also impart other bio-functional properties to achieve diverse clinical requirements.This review analyzes and summarizes the most recent developments in popular coating technologies,including micro-arc oxidation,electrophoretic deposition,chemical conversion,anodic oxidation,layered double hydroxide,and sol-gel coatings.Considering inevitable damages under complex service conditions,smart self-healing coatings are also introduced in each coating technology.The existing issues and future perspectives are finally discussed to facilitate applications of Mg alloys as biomedical materials in the medical industry.
基金financially supported by the National Natural Science Foundation of China(No.52473097)the Fundamental Research Funds for the Central Universities(No.24X010301678)Shanghai Jiao Tong University 2030 Initiative(No.WH510363002/002)。
文摘Incorporating a low density of ester units into the backbone of polyethylene materials enhances their sustainability and recyclability while maintaining the main material properties of polyethylenes.Here we report a new way to access degradable polyethylene materials with a low content of in-chain ester units via mechanochemical backbone editing.Initially,ester groups are incorporated as side groups through catalytic copolymerization of ethylene with a cyclobutene-fused lactone monomer(CBL),yielding polyethylene materials with high molecular weights and adjustable thermomechanical properties.Subsequent solid-state ball-milling treatment selectively introduces side-chain ester groups into the main chain of the polyethylene materials via force-induced cycloreversion of the cyclobutane units.Under acidic conditions,hydrolysis of the resultant polyethylene materials with in-chain ester units facilitates further degradation into oligomers.
文摘The increasing interest in Mg-Zn binary alloys as temporary implant materials is attributed to their outstanding biocompatibility,biodegradability,and favourable mechanical properties.However,their application is constrained by high degradation rates in the physiological environment,resulting in the release of hydrogen gas and a rapid decline in mechanical properties.Additionally,the material's biocompatibility is contingent upon its degradability.Researchers have demonstrated that addressing these issues is possible through strategies such as controlling Zn content,employing thermo-mechanical processing to achieve suitable microstructures,and applying surface coatings.This manuscript provides a comprehensive review of published literature on Mg-Zn alloys,exploring the challenges and outlining future research directions in this field.
基金financially supported by the fund of the Science and Technology Development Plan Project of Jilin Province of China(No.20240304161SF)the Science and Technology Development Plan Project of Jilin Province of China(No.20220203019SF)+1 种基金the Science and Technology Bureau of Changchun City of China(Nos.23SH11,23SH08)the Chinese Science Academy(Changchun Branch)(No.2024SYHZ0038).
文摘Poly(lactic acid)(PLA)is a biodegradable and eco-friendly polymer that is increasingly being incorporated into various applications in contemporary society.However,the limited stability of PLA-based products remains a significant challenge for their broader use in various applications.In this study,poly(L-lactic acid)(PLLA)/poly(D-lactic acid)(PDLA)melt-blown nonwovens were prepared by melt spinning.The structure,thermal properties,thermal stability,biodegradability and crystalline morphology of the melt-blown nonwovens were investigated.DSC and WAXD confirmed the formation of stereocomplex(SC)crystallites in the PLLA matrix.The storage modulus(G′),loss modulus(G″),and complex viscosity(∣η^(*)∣)of the PLLA/PDLA blend increased with an increase in SC crystallite content.The thermal degradation temperatures of PLLA/PDLA melt-blown nonwovens increased with the incorporation of SC crystallites,and the maximum rate of decomposition increased to 385.5℃,thus enhancing the thermal stability.Compared with neat PLLA melt-blown nonwovens,the hydrophobicity of PLLA/PDLA melt-blown nonwovens was improved,and WCA increased to 139.7°.The SC crystallites were more resistant to degradation by proteinase K compared to neat PLLA.However,the degradation rate of PLLA/PDLA melt-blown nonwovens remained at a high level.This work provides an effective strategy to obtain high-performance PLLA melt-blown nonwovens.
基金Funding support of this work was carried out within the governmental task#075-00319-25-00.
文摘A study of the effect of rotary swaging(RS)at 350℃ on mechanical properties,corrosion resistance and biocompatibility in vitro and in vivo of biodegradable Mg-1%Zn-0.6%Ca alloy was conducted.It is shown that the formation of a recrystallized microstructure after RS with a grain size of 3.2±0.2μm leads to an increase in the strength of the alloy without reduction of level of ductility and corrosion resistance.At the same time,aging of the quenched alloy at 100℃ for 8 h leads to a slight increase in strength,but significantly reduces its ductility and corrosion resistance.The study of the degradation process of the alloy in the quenched state and after RS,both under in vitro and in vivo conditions,did not reveal a significant difference between these two microstructural states.However,an increase in the duration of incubation of the alloy in a complete growth medium from 4 h to 24 days leads to a decrease in the degradation rate(DR)by 4times(from~2 to~0.5 mm/year)due to the formation of a dense layer of degradation products.The study of biocompatibility in vitro did not reveal a significant effect of RS on the hemolytic and cytotoxic activity of the alloy.No signs of systemic toxicity were observed after subcutaneous implantation of alloy samples into mice before and after RS.However,it was found that RS promotes uniform degradation of the alloy over the entire contact surface.In summary,RS at 350℃ allows to increase the strength of Mg-1%Zn-0.6%Ca alloy up to348±5 MPa at a ductility level of 17.3±2.8%and a DRin vivoequal to 0.56±0.12 mm/year without impairing its biocompatibility in vitro and in vivo.
基金supported by the National Key R&D Program of China(No.2023YFA1506804)the National Natural Science Foundation of China(Nos.22471110,22171111,22131007 and 22071093)+1 种基金the Science Foundation of Gansu Province of China(No.22JR5RA406)the Fundamental Research Funds for the Central Universities(No.lzujbky-2023-15)。
文摘Most commercial plastics cannot easily degrade,which raises a number of sustainability issues.To address the current problem of plastic pollution,the research and development of easily degradable and recyclable polymers has become an attractive subject.Herein,a new monomer of thiosalicylic methyl glycolide(TSMG)was synthesized using one-pot method and high molecular weight poly(thiosalicylic methyl glycolide)(PTSMG,M_(n) up to 300 kDa)can be obtained via the ring-opening polymerization(ROP)of TSMG.PTSMG exhibits good closed-loop recyclability and hydrolytic degradability,where PTSMG can generate pristine monomers through sublimation thermal depolymerization conditions due to the presence of thiophenol ester bond in the polymer chains,and can be degraded rapidly in aqueous solution,which provides a potential solution to the current plastic pollution problem.
基金funded by the National Key Research and Devel-opment Program of China(2018YFE0104200)the National Natural Science Foundation of China(52175274,82172065,and 51875310)+1 种基金the Tsinghua-Toyota Joint Research Fund,the Tsinghua Precision Medicine Foundationthe Cross-Strait Tsinghua Research Insti-tute Fund.
文摘Biodegradable magnesium(Mg)alloys exhibit excellent biocompatibility,adequate mechanical properties,and osteogenic effect.They can contribute to complete recovery of damaged tissues without concerns about a second surgery and have achieved clinical applications in orthopedic and cardiovascular fields.Porous scaffolds can provide functions such as bone integration and adjustable mechanical properties,thus widely used for bone repair.Additive manufacturing(AM)offers the advantages of design freedom and high precision,enabling the reliable production of porous scaffolds with customized structures.The combination of biodegradable Mg alloys,porous scaffolds,and AM processes has created tremendous opportunities for the precision treatment of bone defects.This article reviews the current development in the additive manufacturing process and design of Mg alloy biodegradable orthopedic implants,fo-cusing on chemical compositions,structural design,surface treatment,and their effects on mechanical properties,degradation behavior,and biocompatibility.Finally,the future perspective of porous Mg alloy biodegradable orthopedic implants is proposed.
基金financially supported by National Key Research and Development Program of China(No.2021YFB3800900)the National Natural Science Foundation of China(Nos.51925305,51833010 and 52203183)+2 种基金Natural Science Foundation of Xiamen,China(No.3502Z202371004)Fundamental Research Funds for the Central Universities(No.20720230004)the talent cultivation project Funds for the Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(No.HRTP-[2022]52)。
文摘Polyethyleneimine(PEI),as a widely used polymer material in the field of gene delivery,has been extensively studied for modification and shielding to reduce its cytotoxicity.However,research aimed at preparing degradable PEI is scarce.In this work,the hydrogen peroxide(H_(2)O_(2))oxidation method was used to introduce degradable amide groups in the PEI and a series of oxidized PEI22k(oxPEI22k)with different degrees of oxidation were synthesized by regulating the dosage of H_(2)O_(2).The relationship between the oxidation degree of oxPEI22k and the gene transfection efficiency of oxPEI22k was studied in detail,confirming that the oxPEI22k with oxidation degrees of 16.7%and 28.6%achieved improved transfection efficiency compared to unmodified PEI.These oxPEI22k also proved reduced cytotoxicity and improved degradability.Further,this strategy was extended to the synthesis of low-molecular-weight oxPEI1.8k.The oxPEI1.8k with suitable oxidation degree also achieved improved transfection efficiency and reduced cytotoxicity.In brief,this work provided high-efficiency and low-cytotoxicity degradable gene delivery carriers by regulating the oxidation degree of PEI,which was of great significance for promoting clinical applications of PEI.
基金the financial support from the National Natural Science Foundation of China(No.22274159)。
文摘The construction of enzyme reactors based on metal-organic frameworks(MOFs)as the immobilized matrix is a proven strategy that has achieved the widespread application of enzymes across industries.Although many MOFs and a variety of strategies have been developed,a formidable challenge remains in maintaining the high enzyme activity with excellent recyclability and tolerance for harsh conditions.Herein,using degradable redox stimuli-responsive liposomes as the templates with microporous MOFs(M-MOFs)as the hosts for enzyme encapsulation,a series of enzyme reactors(enzyme@M-MOFs)was designed and created.Based on the premise of enhancing enzyme protection in the harsh environment,this strategy provided a high degree-of-freedom space via removal of liposomes that improved the conformational freedom of the enzymes,promoted the mass transfer of substrates and products,and greatly boosted the catalytic activity.Importantly,the strategy had good universality and was applied to various liposomes,M-MOFs and enzymes.Additionally,the co-encapsulation of different enzymes with synergistic functions was performed using the M-MOFs platform.This study solved the problems of the conformation limitation of enzymes and mass transfer resistance of substrates and products using the proposed enzyme@M-MOFs,providing a new approach for the construction of biological cascade reaction devices based on MOFs materials.
基金supported by National Natural Science Foundation of China(NSFC,Nos.21971230,U19B6001,22201003)Excellent Research and Innovation Team Project of Anhui Province(No.2022AH010001)Anhui Province Key Laboratory of Environment-friendly Polymer Materials。
文摘Introducing covalently crosslinked network to polymer matrix can merge the advantages in reprocessing and durability of polymers.In this contribution,a series of high-performance vitrimeric elastomers were achieved via polycondensation.The topological structures of polymers were tuned by varying the feeding ratios of bisacetoacetate,hex–substituted bisacetoacetate,bisamine and tris(2-aminoethyl)amine.With these structural manipulations,the vitrimeric elastomers presented great elastic recovery properties(strain recovery value up to 80%)benefiting from the introduction of long chain branch.Furthermore,the elastomers exhibited excellent reprocessing property,water vapor/oxygen barrier and adhesive properties.Specially,the elastomers could be degraded into monomer under acid conditions which enabled the elastomer synthesis again in closed loop recycling system.The ease of the polycondensation in this work to prepare highly elastic and recyclable vitrimeric elastomers demonstrated exciting opportunities for the synthesis of sustainable polymers.
文摘Biodegradable magnesium alloys have been widely used in medical implants. But safety concerns were put forward for the high degradation rate of biodegradable magnesium alloy. The optimal biodegradable magnesium alloys that give rise to the desired degradation rate hasn’t yet to be defined. Assessing the degradation rate of biodegradable magnesium alloys involves in vitro testing, in vivo testing, numerical modeling, understanding the factors influencing their degradation in physiological environments, biocompatibility testing, and clinical studies. It is important to standardize analytical tools aimed at assessing the degradation rate of biodegradable magnesium alloys. It is advisable to identify the threshold for safe degradation rate of biodegradable magnesium alloys in biomedical applications.
