This study proposes to use the unconfined compressive strength(UCS)and the bender element(BE)tests for determining the strength and the initial small-strain shear modulus of Bangkok soft marine clay improved by cement...This study proposes to use the unconfined compressive strength(UCS)and the bender element(BE)tests for determining the strength and the initial small-strain shear modulus of Bangkok soft marine clay improved by cement and polyester fibers.This study varies the content of admixed cement(1%–20%)and polyester fibers(0–20%),including the curing time(3–28 d)for preparing 360 samples.Moreover,this study uses the Michaelis-Menten kinetics concept to model cement hydration saturation.From the study,it is concluded as follows.The modelled results reveals that at least 10%cement and 1%polyester fiber are recommended to attain the 28-d UCS standards(294 kPa)for highway subgrade materials in Thailand.This also fulfils sustainable construction due to reducing normal-use cement from 20%to 10%.Unfortunately,the addition of polyester fibers into the Bangkok clay with at least 5%cement reduces shear modulus by 1.12–1.32 times.The Abram's relationship between shear modulus and the mixing-water-to-cement ratio is found time-dependent.From the composite theory,the BE detects the polyester fiber zone as a defect in the Bangkok clay(matrix)with 5%–20%cement.So,the 28-d shear modulus in the polyester fiber zone is negative(up to0.034 MPa for 20%fiber),similar to softening phenomenon in concrete cracking(negative stiffness).For the 28-d shear modulus of fiber zone,the optimum cement content is around 2%for the positive influences of polyester fibers.Experimentally,the timedependent normalized UCS for 10%and 20%cement is compatible with other studies,and its development rate increases with the cement content as 0.3017,0.3172 and 0.3204 for 5%,10%and 20%cement,respectively.The 28-d relationship between shear modulus and UCS shows that low-cement soft clay requires high polyester fiber content(5%–20%)to activate UCS improvement.However,the soft clay with enough cement(20%)causes the uniformly distributed UCS improvement.展开更多
The integration of interfacial photothermal conversion and hydrovoltaic effect into bifunctional evaporators has emerged as a hopeful approach to address water and energy scarcities.However,developing low-cost bifunct...The integration of interfacial photothermal conversion and hydrovoltaic effect into bifunctional evaporators has emerged as a hopeful approach to address water and energy scarcities.However,developing low-cost bifunctional evaporators and elucidating the freshwater-electricity co-generation mechanism remain challenging.In this work,we prepare porous carbon from waste polyester through a metalorganic framework(MOF)-assisted carbonization strategy and subsequently fabricate a bifunctional evaporator for freshwater-hydroelectricity co-generation.The porous carbon contains rich oxygen-containing groups and shows hierarchical micro-and mesopores with a high specific surface area of 904 m^(2)g^(-1).The porous carbon-based evaporator shows broadband and high light absorption,localized thermal management,good hydrophilicity,and high flexibility.Benefiting from these merits,it achieves high-performance freshwater and hydroelectricity co-generation,with the opencircuit voltage of 250 mV,the short-circuit current of 14μA,and the evaporation rate of 2.34 kg m^(-2)h^(-1).Hence,it is ranked among the most efficient freshwater-hydroelectricity co-generator.Additionally,the weakened hydrogen-bonding network reduces water evaporation enthalpy to 1.7 kJ g^(-1).Mechanistic investigations reveal that selective Na+interaction induces differential ion migration rate to generate streaming potential,as evidenced by molecular dynamics simulations.Meanwhile,the photothermal effect enhances voltage output by promoting interfacial ion concentration gradients.During the outdoor freshwater-electricity co-generation,it shows the voltage output of 250 mV and freshwater production of 2.34 kg m-2.This work not only puts forward a new platform to fabricate advanced evaporators from low-cost waste plastics but also unravels the freshwater-electricity co-generation mechanism,offering scalable strategies to tackle freshwater and energy crises.展开更多
The efficient recycling of poly(ethylene terephthalate)and poly(butylene terephthalate),the most extensively produced plastics,is essential for reducing global carbon emissions and the current dependence on fossil res...The efficient recycling of poly(ethylene terephthalate)and poly(butylene terephthalate),the most extensively produced plastics,is essential for reducing global carbon emissions and the current dependence on fossil resources.However,the chemical recycling of polyesters primarily involves polymer-to-monomer and monomer-to-polymer processes,resulting in significant greenhouse gas emissions owing to significant electricity and fuel consumption.Herein,this research reports a simple and efficient one-pot polymer-to-polymer upcycling process that directly converts these two polyester wastes into biodegradable thermoplastic poly(ether ester)s using poly(tetramethylene ether)glycol(PTMG).The synthesized series of poly((ET-co-BT)-mb-PTMG)(PEBTG)exhibit a maximum tensile strength of 68 MPa,with 85%weight loss after 20 weeks in composted soil.Techno-economic analysis and life cycle assessment indicate that PEBTG is more cost-competitive and environmentally beneficial than currently existing plastics derived from fossil fuels,such as polypropylene and polybutylene adipate terephthalate.Once de-risked,the proposed upcycling strategy for polymer waste can be extended to expedite the development of a sustainable plastic economy.展开更多
The asymmetric alternating copolymerization of meso-epoxide and cyclic anhydrides provides an efficient access to enantiopure polyesters.Contrary to the extensive investigation of the stereochemistry resulting from ep...The asymmetric alternating copolymerization of meso-epoxide and cyclic anhydrides provides an efficient access to enantiopure polyesters.Contrary to the extensive investigation of the stereochemistry resulting from epoxide building block,the chirality from anhydride and the configurational match with epoxide remain elusive.Herein,we discover that the bimetallic chromium catalysts have led to an obvious enhancement in terms of reactivity and enantioselectivity for the asymmetric copolymerization of meso-epoxide with various non-symmetric chiral anhydrides.Up to 97%ee was obtained during the asymmetric copolymerization of cyclohexene oxide(CHO)with(R)-methylsuccinic anhydride(R-MSA),and three-or four-carbon chiral centers were simultaneously installed in the aliphatic polyester backbone.In particular,the different combinations of stereochemistry in epoxide and anhydride building blocks considerably affect the thermal properties and crystalline behaviors of the resulting polyesters.This study uncovers an interesting method for regulating polymer crystallinity via matching the chirality of different monomers.展开更多
The thermotropic liquid crystal polyester(TLCP)fiber is an increasingly important strategic high-performance fiber.In this paper,the TLCP was prepared by two-step melt polymerization using 4-hydroxybenzoic acid(HBA)an...The thermotropic liquid crystal polyester(TLCP)fiber is an increasingly important strategic high-performance fiber.In this paper,the TLCP was prepared by two-step melt polymerization using 4-hydroxybenzoic acid(HBA)and 6-hydroxy-2-naphthoic acid(HNA)as comonomers at a molar ratio of 7∶3.The structure of TLCP was confirmed by the Fourier transform infrared(FTIR)spectrometer and nuclear magnetic resonance(NMR)spectrometer.The thermal and rheological properties of TLCP before and after heat treatment were analyzed systematically by the differential scanning calorimeter(DSC),dynamic mechanical analyzer(DMA)and high-temperature rotational rheometer.The results revealed that the melting temperature,glass transition temperature and melt viscosity of the TLCP increased significantly after heat treatment.It indicates that the crystallization of the TLCP is perfect,and solid-phase condensation occurs during heat treatment,which increases its molecular mass.In conclusion,heat treatment at a temperature below but close to the melting temperature can effectively regulate the structure and properties of the TLCP,and the results of this study can provide a reference for the high strengthening of TLCP fibers.展开更多
Chemical modification of polymers represents a pivotal method for achieving functionalized polymer materials.However,due to the lack of post-functional handle,the chemical modification of polyester materials remains a...Chemical modification of polymers represents a pivotal method for achieving functionalized polymer materials.However,due to the lack of post-functional handle,the chemical modification of polyester materials remains a significant challenge.Ring-opening copolymerization of cyclic anhydride and epoxides is a powerful approach to synthesize polyesters.In this work,we for the first time demonstrate the functionalizability of polyesters synthesized with brominated anhydride monomers.The post-functionalization is amenable to a wide variety of reactive groups and reactions with high yields.With multiple well-established functionalization pathways of brominated polyester materials and optimized the conditions for the modification reactions,a series of functionalized polyester materials can be obtained with high yields,providing new insights for the research about functionalization of polymers.展开更多
To enhance the properties of bio-based polyesters,enabling them to more closely mimic the characteristics of terephthalate-based materials,a series of aliphatic-aromatic copolyesters(P_(1)–P_(4))were synthesized via ...To enhance the properties of bio-based polyesters,enabling them to more closely mimic the characteristics of terephthalate-based materials,a series of aliphatic-aromatic copolyesters(P_(1)–P_(4))were synthesized via melt polycondensation.Diester monomers M and N were synthesized via the Williamson reaction,using lignin-derived 2-methoxyhydroquinone,methyl 4-chloromethylbenzoate,and methyl chloroacetate as starting materials.Hydroquinone bis(2-hydroxyethyl)ether(HQEE)and 1,4-cyclohexanedimethanol(CHDM)were employed as cyclic segments,while 1,4-butanediol(BDO)and 1,6-hexanediol(HDO)served as alkyl segments within the copolymer structures.The novel copolyesters exhibited molecular weights(Mw)in the range of 5.25×10^(4)–5.87×10^(4) g/mol,with polydispersity indices spanning from 2.50–2.66.Evaluation of the structural and thermomechanical properties indicated that the inclusion of alkyl segments induced a reduction in both crystallinity and molecular weight,while significantly improving the flexibility,whereas cyclic segments enhanced the processability of the copolyesters.Copolyesters P_(1) and P_(2),due to the presence of rigid segments(HQEE and CHDM),displayed relatively high glass transition temperatures(Tg>80℃)and melting temperatures(Tm>170℃).Notably,P_(2),incorporating CHDM,exhibited superior elongation properties(272%),attributed to the enhanced chain mobility resulting from its trans-conformation,while P_(1) was found to be likely brittle owing to excessive chain stiffness.Biodegradability assessment using earthworms as bioindicators revealed that the copolyesters demonstrated moderate degradation profiles,with P_(2) exhibiting a degradation rate of 4.82%,followed by P_(4) at 4.07%,P_(3) at 3.65%,and P_(1) at 3.17%.The higher degradation rate of P_(2) was attributed to its relatively larger d-spacing and lower toxicity,which facilitated enzymatic hydrolytic attack by microorganisms.These findings highlight the significance of optimizing the structural chain segments within aliphatic-aromatic copolyesters.By doing so,it is possible to significantly enhance their properties and performance,offering viable bio-based alternatives to petroleum-based polyesters such as polyethylene terephthalate(PET).展开更多
Aliphatic polyesters and polycarbonates are among the promising sustainable polymers,which exhibit unique degradability and chain-chain interactions owing to their heterofunctionality.However,monocomponent aliphatic p...Aliphatic polyesters and polycarbonates are among the promising sustainable polymers,which exhibit unique degradability and chain-chain interactions owing to their heterofunctionality.However,monocomponent aliphatic polyesters and polycarbonates usually suffer from inferior properties and functionalities.By contrast,precisely modulated block copolymers composed of polyesters and polycarbonates give rise to sustainable materials with tailored performance.An efficient approach to synthesize the block copolymers is the ring-opening(co)polymerization of the heterocycle monomers.Herein,this review presents the heterocycle monomer ring-opening(co)polymerization for the formation of sequence-controlled block polyesters and polycarbonates.Available synthetic strategies,different monomers,monomer combinations and the catalyst systems for the formation of different block polyesters and polycarbonates are summarized.展开更多
Renewable 2,5-furandicarboxylic acid-based polyesters are one of the most promising materials for achieving plastic replacement in the age of energy and environmental crisis.However,their properties still cannot compe...Renewable 2,5-furandicarboxylic acid-based polyesters are one of the most promising materials for achieving plastic replacement in the age of energy and environmental crisis.However,their properties still cannot compete with those of petrochemical-based plastics,owing to insufficient molecular and/or microstructure designs.Herein,we utilize the Ti_(3)C_(2)T_(x)-based MXene nanosheets for decorating carbon nanotube(CNT)and obtaining the structurally stable and highly dispersed dendritic heterostructured MXene@CNT,that can act as multi-roles,i.e.,polycondensation catalyst,crystal nucleator,and interface enhancer of polyester.The biobased MXene@CNT/polybutylene furandicarboxylate(PBF)(denoted as MCP)nanocomposites are synthesized by the strategy of“in situ catalytic polymerization and hot-pressing”.Benefiting from the multi-scale interactions(i.e.,covalent bonds,hydrogen bonds,and physical interlocks)in hybrid structure,the MCP presents exceptional mechanical strength(≈101 MPa),stiffness(≈3.1 GPa),toughness(≈130 MJ m^(-3)),and barrier properties(e.g.,O_(2)0.0187 barrer,CO_(2)0.0264 barrer,and H2O 1.57×10^(-14) g cm cm^(-2) s Pa)that are higher than most reported bio-based materials and engineering plastics.Moreover,it also displays satisfactory multifunctionality with high reprocessability(90%strength retention after 5 recycling),UV resistance(blocking 85%UVA rays),and solvent-resistant properties.As a state-of-art high-performance and multifunctional material,the novel bio-based MCP nanocomposite offers a more sustainable alternative to petrochemical-based plastics in packaging and engineering material fields.More importantly,our catalysis-interfacial strengthening integration strategy opens a door for designing and constructing high-performance bio-based polyester materials in future.展开更多
An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromatic polyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of t...An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromatic polyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB(2) monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionyl chloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminated material (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully to avoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weight distributions and thermal properties, are reported.展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
A series of novel thermotropic liquid crystalline polyesters bearing nonlinear optical azobenzene side group were synthesized by high temperature solution polycondensation and their structures,thermal stability, phas...A series of novel thermotropic liquid crystalline polyesters bearing nonlinear optical azobenzene side group were synthesized by high temperature solution polycondensation and their structures,thermal stability, phase transition behavior and crystallinity were characterized by IR,elemental analysis, TG-DTA, polarizing optical microscope (POM) equipped with a hot stage and X-ray diffraction techniques. The results demonstrate that all the synthesized polyesters exhibit nematic liquid crystalline phases and show relatively high glass transition temperatures and good thermal stability.展开更多
Copolyesters having secondary and tertiary amine salt groups in the main and side chains are prepared by chemoselective polymerization. These copolyesters are soluble in a 10% aqueous solution of poly(vinyl alcohol) ...Copolyesters having secondary and tertiary amine salt groups in the main and side chains are prepared by chemoselective polymerization. These copolyesters are soluble in a 10% aqueous solution of poly(vinyl alcohol) (PVA) at 90 degree C and act as plasticizer in the blend films cast from the solution. Only a glass transition temperature is observed for all these blends indicating the formation of compatible blends from these polyesters with PVA. These blends exhibit manifold characteristics such as ionic conductivity, complex formation with metal ions, absorption of moisture and color changes. The electric conductivity of the copolyesters and blends is in the range of 10** minus **6 Scm** minus **1. The blends with PVA forms complexes with Cu**2** plus and Co**2** plus . The coordination structure with two chelate rings is suggested for these polymer blend/metal complexes. (Author abstract) 10 Refs.展开更多
Waterborne elastic polyester (WEP) with different content of hard polyester was applied in the maize starch (MS) based composites (MS/WEP) via solution casting method.The effects of WEP with different contents of hard...Waterborne elastic polyester (WEP) with different content of hard polyester was applied in the maize starch (MS) based composites (MS/WEP) via solution casting method.The effects of WEP with different contents of hard polyester on the structure and properties of starch were studied by Fourier transform infrared,X-ray diffraction,ultraviolet-visible,tensile test,differential scanning calorimeter,thermogravimetric analysis and moisture measurement.The experimental results show that the addition of WEP does not change the crystalline type of starch,and only reduces the crystallinity of starch.And the structure and properties of MS/WEP are related to not only the content of starch but also the microstructure of WEP or the content of hard polyester in WEP.Waterborne elastic polyester with 30wt% hard polyester (WEP30) has the best modification effect on the maize starch among all the WEPs.For example,MS/WEP30 film has the optimum toughness,aging resistance and transmittance,the lowest crystallinity and glass transition temperature among all the MS/WEP films,and the lower moisture content.It is related to the compatibility between starch and WEP,resulting from the number of physical crosslinking points in WEP..展开更多
A series of degradable polyesters was synthesized via melt polymerization of 3,6-dioxaoctane-1,8-dioic acid and five different diols,catalyzed by antimony trioxide(Sb_(2)O_(3)).The polymers were characterized by FT-IR...A series of degradable polyesters was synthesized via melt polymerization of 3,6-dioxaoctane-1,8-dioic acid and five different diols,catalyzed by antimony trioxide(Sb_(2)O_(3)).The polymers were characterized by FT-IR and ^(1)H NMR spectroscopy,gel permeation chromatography(GPC)and differential scanning calorimetry(DSC)analysis.The polydispersity index(PDI=M_(w)/M_(n))of the polyesters ranged from 1.55 to 1.99,the weight-average molecular weight(M_(w))from 1.8×10^(4) to 3.2×10^(4) Da,the melting point from 63 to 123℃,and the highest decomposition temperature observed was 363℃.The influence of the structure of the polymer chain on hydrolytic degradability was investigated with tests performed at three different values of pH.The findings obtained provide useful insight for the molecular design and the synthesis of degradable polyesters.展开更多
Unsaturated polyester resin(UPR)/acrylate-terminated polyurethane(ATPU)/organo-modified montmorillonite(OMMT)nanocomposites were prepared by the in situ intercalative polymerization method.Samples were prepared by the...Unsaturated polyester resin(UPR)/acrylate-terminated polyurethane(ATPU)/organo-modified montmorillonite(OMMT)nanocomposites were prepared by the in situ intercalative polymerization method.Samples were prepared by the sequential mixing,i.e.mixture of the ATPU and styrene(S)and OMMT were prepared in the first step;UPR was then added to the pre-intercalates of ATPU/S/OMMT.Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT.Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites,but the tensile strength,flexural strength and heat resistance of the materials are obviously decreased.When the weight ratio between UPR,ATPU and OMMT were 82:15:3,the impact strength and heat distortion-temperature of nanocomposite were greatly improved,meanwhile there was little change for other properties of the nanocomposites.The synergistic enhancement effects of ATPU and OMMT on the composites were observed.The structures and morphology of the composites were investigated by X-ray diffraction,scanning electron microscopy and transmission electron microscopy.展开更多
Wood-based bilayer solar evaporators,which possess cooperative advantages of natural wood and photothermal conversion coating including fast water transportation,low heat conduction,renewability,and high light absorba...Wood-based bilayer solar evaporators,which possess cooperative advantages of natural wood and photothermal conversion coating including fast water transportation,low heat conduction,renewability,and high light absorbability,hold great promise for water purification.However,previous studies suffer from low evaporation rates and high cost of coatings,and lack a deep understanding how the porous structures of coating layer function.Herein,a novel bilayer solar evaporator is designed through facile surface coating of wood by low-cost porous carbon from controlled carbonization of polyester waste.The porous carbon bears rich oxygen-containing groups,well-controlled micro-/meso-/macropores,and high surface areas(1164 m^(2) g^(−1)).It is proved that porous carbon improves sunlight absorption and promotes the formation of numerous water clusters to reduce water evaporation enthalpy.Owing to these combined features,the bilayer solar evaporator exhibits high evaporation rate(2.38 kg m^(−2) h^(−1)),excellent longterm stability,and good salt resistance.More importantly,a large-scale solar desalination device for outdoor experiments is developed to produce freshwater from seawater.The daily freshwater production amount(3.65 kg m^(−2))per unit area meets the daily water consumption requirement of one adult.These findings will inspire new paradigms toward developing efficient solar steaming technologies for desalination to address global freshwater shortage.展开更多
Acrylate modified polyurethane resin was first synthesized, and interpenetrated with unsaturated polyester resin to form IPNs and gradient IPNs which cured at room temperature. The polymerization process was traced by...Acrylate modified polyurethane resin was first synthesized, and interpenetrated with unsaturated polyester resin to form IPNs and gradient IPNs which cured at room temperature. The polymerization process was traced by an IR spectroscopy technique and the simultaneous interpenetrating techniques were determined. The morphology of these IPNs were estimated by TMA and TEM methods. The results indicated that large amount of interpenetrating and entanglement make T g linked up effectively, and domains between two phases can be in nanometre ranges, which changed with composition ratios. The mechanical properties results showed that IPNs varied from elastomeric to plastic materials. It was noteworthy that, with the introduction of modified groups and the formation of graft construction in IPNs, the miscibility in the systems was improved a lot. These further led to the improved mechanical properties of IPNs with elastomer reinforced and plasticizer toughened as well. The reinforced miscibility between the networks can apparently change mechanical property especially for the gradient ones when the materials are elongated.展开更多
基金allocated by National Science,Research and Innovation Fund(NSRF)King Mongkut's University of Technology North Bangkok(project no.KMUTNB-FF-67-B-44 and KMUTNB-FF-67-B-45)supported by the NSRF through the Program Management Unit for Human Resources&Institutional Development,Research and Innovation(grant no.B40G660036).
文摘This study proposes to use the unconfined compressive strength(UCS)and the bender element(BE)tests for determining the strength and the initial small-strain shear modulus of Bangkok soft marine clay improved by cement and polyester fibers.This study varies the content of admixed cement(1%–20%)and polyester fibers(0–20%),including the curing time(3–28 d)for preparing 360 samples.Moreover,this study uses the Michaelis-Menten kinetics concept to model cement hydration saturation.From the study,it is concluded as follows.The modelled results reveals that at least 10%cement and 1%polyester fiber are recommended to attain the 28-d UCS standards(294 kPa)for highway subgrade materials in Thailand.This also fulfils sustainable construction due to reducing normal-use cement from 20%to 10%.Unfortunately,the addition of polyester fibers into the Bangkok clay with at least 5%cement reduces shear modulus by 1.12–1.32 times.The Abram's relationship between shear modulus and the mixing-water-to-cement ratio is found time-dependent.From the composite theory,the BE detects the polyester fiber zone as a defect in the Bangkok clay(matrix)with 5%–20%cement.So,the 28-d shear modulus in the polyester fiber zone is negative(up to0.034 MPa for 20%fiber),similar to softening phenomenon in concrete cracking(negative stiffness).For the 28-d shear modulus of fiber zone,the optimum cement content is around 2%for the positive influences of polyester fibers.Experimentally,the timedependent normalized UCS for 10%and 20%cement is compatible with other studies,and its development rate increases with the cement content as 0.3017,0.3172 and 0.3204 for 5%,10%and 20%cement,respectively.The 28-d relationship between shear modulus and UCS shows that low-cement soft clay requires high polyester fiber content(5%–20%)to activate UCS improvement.However,the soft clay with enough cement(20%)causes the uniformly distributed UCS improvement.
基金supported by the National Natural Science Foundation of China(52373099)Interdisciplinary Research Program of Huazhong University of Science and Technology(5003013161)+1 种基金Innovation and Talent Recruitment Base of New Energy Chemistry and Device(B21003)Hubei Integrative Technology and Innovation Center for Advanced Fiberous Materials(XC202502)。
文摘The integration of interfacial photothermal conversion and hydrovoltaic effect into bifunctional evaporators has emerged as a hopeful approach to address water and energy scarcities.However,developing low-cost bifunctional evaporators and elucidating the freshwater-electricity co-generation mechanism remain challenging.In this work,we prepare porous carbon from waste polyester through a metalorganic framework(MOF)-assisted carbonization strategy and subsequently fabricate a bifunctional evaporator for freshwater-hydroelectricity co-generation.The porous carbon contains rich oxygen-containing groups and shows hierarchical micro-and mesopores with a high specific surface area of 904 m^(2)g^(-1).The porous carbon-based evaporator shows broadband and high light absorption,localized thermal management,good hydrophilicity,and high flexibility.Benefiting from these merits,it achieves high-performance freshwater and hydroelectricity co-generation,with the opencircuit voltage of 250 mV,the short-circuit current of 14μA,and the evaporation rate of 2.34 kg m^(-2)h^(-1).Hence,it is ranked among the most efficient freshwater-hydroelectricity co-generator.Additionally,the weakened hydrogen-bonding network reduces water evaporation enthalpy to 1.7 kJ g^(-1).Mechanistic investigations reveal that selective Na+interaction induces differential ion migration rate to generate streaming potential,as evidenced by molecular dynamics simulations.Meanwhile,the photothermal effect enhances voltage output by promoting interfacial ion concentration gradients.During the outdoor freshwater-electricity co-generation,it shows the voltage output of 250 mV and freshwater production of 2.34 kg m-2.This work not only puts forward a new platform to fabricate advanced evaporators from low-cost waste plastics but also unravels the freshwater-electricity co-generation mechanism,offering scalable strategies to tackle freshwater and energy crises.
基金supported by grants from the National Research Foundation of Korea(NRF),funded by the Korean government(RS-2024-00408795 and RS-2024-00466473).
文摘The efficient recycling of poly(ethylene terephthalate)and poly(butylene terephthalate),the most extensively produced plastics,is essential for reducing global carbon emissions and the current dependence on fossil resources.However,the chemical recycling of polyesters primarily involves polymer-to-monomer and monomer-to-polymer processes,resulting in significant greenhouse gas emissions owing to significant electricity and fuel consumption.Herein,this research reports a simple and efficient one-pot polymer-to-polymer upcycling process that directly converts these two polyester wastes into biodegradable thermoplastic poly(ether ester)s using poly(tetramethylene ether)glycol(PTMG).The synthesized series of poly((ET-co-BT)-mb-PTMG)(PEBTG)exhibit a maximum tensile strength of 68 MPa,with 85%weight loss after 20 weeks in composted soil.Techno-economic analysis and life cycle assessment indicate that PEBTG is more cost-competitive and environmentally beneficial than currently existing plastics derived from fossil fuels,such as polypropylene and polybutylene adipate terephthalate.Once de-risked,the proposed upcycling strategy for polymer waste can be extended to expedite the development of a sustainable plastic economy.
基金financially supported by the National Natural Science Foundation of China(Nos.22071016 and 21920102006)。
文摘The asymmetric alternating copolymerization of meso-epoxide and cyclic anhydrides provides an efficient access to enantiopure polyesters.Contrary to the extensive investigation of the stereochemistry resulting from epoxide building block,the chirality from anhydride and the configurational match with epoxide remain elusive.Herein,we discover that the bimetallic chromium catalysts have led to an obvious enhancement in terms of reactivity and enantioselectivity for the asymmetric copolymerization of meso-epoxide with various non-symmetric chiral anhydrides.Up to 97%ee was obtained during the asymmetric copolymerization of cyclohexene oxide(CHO)with(R)-methylsuccinic anhydride(R-MSA),and three-or four-carbon chiral centers were simultaneously installed in the aliphatic polyester backbone.In particular,the different combinations of stereochemistry in epoxide and anhydride building blocks considerably affect the thermal properties and crystalline behaviors of the resulting polyesters.This study uncovers an interesting method for regulating polymer crystallinity via matching the chirality of different monomers.
基金National Key Research and Development Program of China (No.2021YFB3700105)。
文摘The thermotropic liquid crystal polyester(TLCP)fiber is an increasingly important strategic high-performance fiber.In this paper,the TLCP was prepared by two-step melt polymerization using 4-hydroxybenzoic acid(HBA)and 6-hydroxy-2-naphthoic acid(HNA)as comonomers at a molar ratio of 7∶3.The structure of TLCP was confirmed by the Fourier transform infrared(FTIR)spectrometer and nuclear magnetic resonance(NMR)spectrometer.The thermal and rheological properties of TLCP before and after heat treatment were analyzed systematically by the differential scanning calorimeter(DSC),dynamic mechanical analyzer(DMA)and high-temperature rotational rheometer.The results revealed that the melting temperature,glass transition temperature and melt viscosity of the TLCP increased significantly after heat treatment.It indicates that the crystallization of the TLCP is perfect,and solid-phase condensation occurs during heat treatment,which increases its molecular mass.In conclusion,heat treatment at a temperature below but close to the melting temperature can effectively regulate the structure and properties of the TLCP,and the results of this study can provide a reference for the high strengthening of TLCP fibers.
基金financially supported by the National Key R&D Program of China(No.2021YFA1501700)the Science and Technology Development Plan of Jilin Province(Nos.20230101042JC and 20210201059GX)+1 种基金the National Natural Science Foundation of China,Basic Science Center Program(No.51988102)the National Natural Science Foundation of China(Nos.52203017 and 52073272)。
文摘Chemical modification of polymers represents a pivotal method for achieving functionalized polymer materials.However,due to the lack of post-functional handle,the chemical modification of polyester materials remains a significant challenge.Ring-opening copolymerization of cyclic anhydride and epoxides is a powerful approach to synthesize polyesters.In this work,we for the first time demonstrate the functionalizability of polyesters synthesized with brominated anhydride monomers.The post-functionalization is amenable to a wide variety of reactive groups and reactions with high yields.With multiple well-established functionalization pathways of brominated polyester materials and optimized the conditions for the modification reactions,a series of functionalized polyester materials can be obtained with high yields,providing new insights for the research about functionalization of polymers.
基金financially supported by State Administration of Foreign Experts Affairs(SAFEA)through the High-End Foreign Expert Program(No.BG2021227001)postdoctoral funding from Wuhan University of Science and Technology(No.105008701)。
文摘To enhance the properties of bio-based polyesters,enabling them to more closely mimic the characteristics of terephthalate-based materials,a series of aliphatic-aromatic copolyesters(P_(1)–P_(4))were synthesized via melt polycondensation.Diester monomers M and N were synthesized via the Williamson reaction,using lignin-derived 2-methoxyhydroquinone,methyl 4-chloromethylbenzoate,and methyl chloroacetate as starting materials.Hydroquinone bis(2-hydroxyethyl)ether(HQEE)and 1,4-cyclohexanedimethanol(CHDM)were employed as cyclic segments,while 1,4-butanediol(BDO)and 1,6-hexanediol(HDO)served as alkyl segments within the copolymer structures.The novel copolyesters exhibited molecular weights(Mw)in the range of 5.25×10^(4)–5.87×10^(4) g/mol,with polydispersity indices spanning from 2.50–2.66.Evaluation of the structural and thermomechanical properties indicated that the inclusion of alkyl segments induced a reduction in both crystallinity and molecular weight,while significantly improving the flexibility,whereas cyclic segments enhanced the processability of the copolyesters.Copolyesters P_(1) and P_(2),due to the presence of rigid segments(HQEE and CHDM),displayed relatively high glass transition temperatures(Tg>80℃)and melting temperatures(Tm>170℃).Notably,P_(2),incorporating CHDM,exhibited superior elongation properties(272%),attributed to the enhanced chain mobility resulting from its trans-conformation,while P_(1) was found to be likely brittle owing to excessive chain stiffness.Biodegradability assessment using earthworms as bioindicators revealed that the copolyesters demonstrated moderate degradation profiles,with P_(2) exhibiting a degradation rate of 4.82%,followed by P_(4) at 4.07%,P_(3) at 3.65%,and P_(1) at 3.17%.The higher degradation rate of P_(2) was attributed to its relatively larger d-spacing and lower toxicity,which facilitated enzymatic hydrolytic attack by microorganisms.These findings highlight the significance of optimizing the structural chain segments within aliphatic-aromatic copolyesters.By doing so,it is possible to significantly enhance their properties and performance,offering viable bio-based alternatives to petroleum-based polyesters such as polyethylene terephthalate(PET).
基金supported by the National Natural Science Foundation of China,Fund for Distinguished Young Scholars(No.52325301)CAS Project for Young Scientists in Basic Research(YSBR-094)the National Natural Science Foundation of China,Basic Science Center Program(No.51988102).
文摘Aliphatic polyesters and polycarbonates are among the promising sustainable polymers,which exhibit unique degradability and chain-chain interactions owing to their heterofunctionality.However,monocomponent aliphatic polyesters and polycarbonates usually suffer from inferior properties and functionalities.By contrast,precisely modulated block copolymers composed of polyesters and polycarbonates give rise to sustainable materials with tailored performance.An efficient approach to synthesize the block copolymers is the ring-opening(co)polymerization of the heterocycle monomers.Herein,this review presents the heterocycle monomer ring-opening(co)polymerization for the formation of sequence-controlled block polyesters and polycarbonates.Available synthetic strategies,different monomers,monomer combinations and the catalyst systems for the formation of different block polyesters and polycarbonates are summarized.
基金financial supports from the National Natural Science Foundation of China(Grant No.NSFC52473104)National Key R&D Program of China(Grant No.2022YFC2104500)+3 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.Y24B040002)Ningbo 2025 Key Scientific Research Programs(Grant No.2022Z160)the China Postdoctoral Science Foundation(Grant No.2023M733601)the Ningbo Natural Science Foundation(Grant No.2023I333&2023J409).
文摘Renewable 2,5-furandicarboxylic acid-based polyesters are one of the most promising materials for achieving plastic replacement in the age of energy and environmental crisis.However,their properties still cannot compete with those of petrochemical-based plastics,owing to insufficient molecular and/or microstructure designs.Herein,we utilize the Ti_(3)C_(2)T_(x)-based MXene nanosheets for decorating carbon nanotube(CNT)and obtaining the structurally stable and highly dispersed dendritic heterostructured MXene@CNT,that can act as multi-roles,i.e.,polycondensation catalyst,crystal nucleator,and interface enhancer of polyester.The biobased MXene@CNT/polybutylene furandicarboxylate(PBF)(denoted as MCP)nanocomposites are synthesized by the strategy of“in situ catalytic polymerization and hot-pressing”.Benefiting from the multi-scale interactions(i.e.,covalent bonds,hydrogen bonds,and physical interlocks)in hybrid structure,the MCP presents exceptional mechanical strength(≈101 MPa),stiffness(≈3.1 GPa),toughness(≈130 MJ m^(-3)),and barrier properties(e.g.,O_(2)0.0187 barrer,CO_(2)0.0264 barrer,and H2O 1.57×10^(-14) g cm cm^(-2) s Pa)that are higher than most reported bio-based materials and engineering plastics.Moreover,it also displays satisfactory multifunctionality with high reprocessability(90%strength retention after 5 recycling),UV resistance(blocking 85%UVA rays),and solvent-resistant properties.As a state-of-art high-performance and multifunctional material,the novel bio-based MCP nanocomposite offers a more sustainable alternative to petrochemical-based plastics in packaging and engineering material fields.More importantly,our catalysis-interfacial strengthening integration strategy opens a door for designing and constructing high-performance bio-based polyester materials in future.
基金The project is supported by the EPSRC and the Youth Science Foundation of Shanghai Higher Education.
文摘An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromatic polyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB(2) monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionyl chloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminated material (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully to avoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weight distributions and thermal properties, are reported.
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
文摘A series of novel thermotropic liquid crystalline polyesters bearing nonlinear optical azobenzene side group were synthesized by high temperature solution polycondensation and their structures,thermal stability, phase transition behavior and crystallinity were characterized by IR,elemental analysis, TG-DTA, polarizing optical microscope (POM) equipped with a hot stage and X-ray diffraction techniques. The results demonstrate that all the synthesized polyesters exhibit nematic liquid crystalline phases and show relatively high glass transition temperatures and good thermal stability.
文摘Copolyesters having secondary and tertiary amine salt groups in the main and side chains are prepared by chemoselective polymerization. These copolyesters are soluble in a 10% aqueous solution of poly(vinyl alcohol) (PVA) at 90 degree C and act as plasticizer in the blend films cast from the solution. Only a glass transition temperature is observed for all these blends indicating the formation of compatible blends from these polyesters with PVA. These blends exhibit manifold characteristics such as ionic conductivity, complex formation with metal ions, absorption of moisture and color changes. The electric conductivity of the copolyesters and blends is in the range of 10** minus **6 Scm** minus **1. The blends with PVA forms complexes with Cu**2** plus and Co**2** plus . The coordination structure with two chelate rings is suggested for these polymer blend/metal complexes. (Author abstract) 10 Refs.
基金Funded by the National Natural Science Foundation of China(No.51603134)the Graduate Program Construction Project Funding of Sichuan University(No.2017KCSJ036)+1 种基金the Opening Project of Key Laboratory of Leather Chemistry and Engeering(Sichuan University)Ministry of Education(SCU2021D005)。
文摘Waterborne elastic polyester (WEP) with different content of hard polyester was applied in the maize starch (MS) based composites (MS/WEP) via solution casting method.The effects of WEP with different contents of hard polyester on the structure and properties of starch were studied by Fourier transform infrared,X-ray diffraction,ultraviolet-visible,tensile test,differential scanning calorimeter,thermogravimetric analysis and moisture measurement.The experimental results show that the addition of WEP does not change the crystalline type of starch,and only reduces the crystallinity of starch.And the structure and properties of MS/WEP are related to not only the content of starch but also the microstructure of WEP or the content of hard polyester in WEP.Waterborne elastic polyester with 30wt% hard polyester (WEP30) has the best modification effect on the maize starch among all the WEPs.For example,MS/WEP30 film has the optimum toughness,aging resistance and transmittance,the lowest crystallinity and glass transition temperature among all the MS/WEP films,and the lower moisture content.It is related to the compatibility between starch and WEP,resulting from the number of physical crosslinking points in WEP..
基金Funded by the Program(BG20190227001)of High-end Foreign Experts of the State Administration of Foreign Experts Affairs(SAFEA)the Coal Conversion and New Carbon Materials Hubei Key Laboratory in Wuhan University of Science and Technology(WKDM201909)。
文摘A series of degradable polyesters was synthesized via melt polymerization of 3,6-dioxaoctane-1,8-dioic acid and five different diols,catalyzed by antimony trioxide(Sb_(2)O_(3)).The polymers were characterized by FT-IR and ^(1)H NMR spectroscopy,gel permeation chromatography(GPC)and differential scanning calorimetry(DSC)analysis.The polydispersity index(PDI=M_(w)/M_(n))of the polyesters ranged from 1.55 to 1.99,the weight-average molecular weight(M_(w))from 1.8×10^(4) to 3.2×10^(4) Da,the melting point from 63 to 123℃,and the highest decomposition temperature observed was 363℃.The influence of the structure of the polymer chain on hydrolytic degradability was investigated with tests performed at three different values of pH.The findings obtained provide useful insight for the molecular design and the synthesis of degradable polyesters.
基金This research was supported by the Science and Technology Key Project of Guangdong(A1070203).
文摘Unsaturated polyester resin(UPR)/acrylate-terminated polyurethane(ATPU)/organo-modified montmorillonite(OMMT)nanocomposites were prepared by the in situ intercalative polymerization method.Samples were prepared by the sequential mixing,i.e.mixture of the ATPU and styrene(S)and OMMT were prepared in the first step;UPR was then added to the pre-intercalates of ATPU/S/OMMT.Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT.Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites,but the tensile strength,flexural strength and heat resistance of the materials are obviously decreased.When the weight ratio between UPR,ATPU and OMMT were 82:15:3,the impact strength and heat distortion-temperature of nanocomposite were greatly improved,meanwhile there was little change for other properties of the nanocomposites.The synergistic enhancement effects of ATPU and OMMT on the composites were observed.The structures and morphology of the composites were investigated by X-ray diffraction,scanning electron microscopy and transmission electron microscopy.
基金supported by the National Natural Science Foundation of China(No.51903099 and 51991353)Huazhong University of Science and Technology(No.3004013134)the 100 Talents Program of the Hubei Provincial Government,and the Innovation and Talent Recruitment Base of New Energy Chemistry and Device(No.B21003).
文摘Wood-based bilayer solar evaporators,which possess cooperative advantages of natural wood and photothermal conversion coating including fast water transportation,low heat conduction,renewability,and high light absorbability,hold great promise for water purification.However,previous studies suffer from low evaporation rates and high cost of coatings,and lack a deep understanding how the porous structures of coating layer function.Herein,a novel bilayer solar evaporator is designed through facile surface coating of wood by low-cost porous carbon from controlled carbonization of polyester waste.The porous carbon bears rich oxygen-containing groups,well-controlled micro-/meso-/macropores,and high surface areas(1164 m^(2) g^(−1)).It is proved that porous carbon improves sunlight absorption and promotes the formation of numerous water clusters to reduce water evaporation enthalpy.Owing to these combined features,the bilayer solar evaporator exhibits high evaporation rate(2.38 kg m^(−2) h^(−1)),excellent longterm stability,and good salt resistance.More importantly,a large-scale solar desalination device for outdoor experiments is developed to produce freshwater from seawater.The daily freshwater production amount(3.65 kg m^(−2))per unit area meets the daily water consumption requirement of one adult.These findings will inspire new paradigms toward developing efficient solar steaming technologies for desalination to address global freshwater shortage.
文摘Acrylate modified polyurethane resin was first synthesized, and interpenetrated with unsaturated polyester resin to form IPNs and gradient IPNs which cured at room temperature. The polymerization process was traced by an IR spectroscopy technique and the simultaneous interpenetrating techniques were determined. The morphology of these IPNs were estimated by TMA and TEM methods. The results indicated that large amount of interpenetrating and entanglement make T g linked up effectively, and domains between two phases can be in nanometre ranges, which changed with composition ratios. The mechanical properties results showed that IPNs varied from elastomeric to plastic materials. It was noteworthy that, with the introduction of modified groups and the formation of graft construction in IPNs, the miscibility in the systems was improved a lot. These further led to the improved mechanical properties of IPNs with elastomer reinforced and plasticizer toughened as well. The reinforced miscibility between the networks can apparently change mechanical property especially for the gradient ones when the materials are elongated.
