Copolymerization is a commonly employed method for optimizing the properties of polymer materials.Incorporating ether segments into polyesters main chain to obtain polyether-polyester copolymers is an effective strate...Copolymerization is a commonly employed method for optimizing the properties of polymer materials.Incorporating ether segments into polyesters main chain to obtain polyether-polyester copolymers is an effective strategy to realize the integration of multiple properties of polyester and polyether,and to develop more high-performance,multi-purpose polymer materials.Herein,the synthesis of poly(ether-ester)s is accessible by employing the biphenyl-linked heterodinuclear salen Cr-AI complex in the presence of PPNCI for the copolymerization of epoxides and£-caprolactone(CL).Monitoring the copolymerization process reveals that catalyst 1 exhibited good performance for the copolymerization of epoxides and CL,affording copolymers with a gradient sequence structure.The dynamic thermomechanical analysis(DMA)study indicates the obtained poly(ether-ester)s possess enhanced flexibility compared with the block copolymers or blend of PPO and PCL homopolymers with the same ratio.This study provides a theoretical basis for the preparation of high-performance polymer materials.展开更多
Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid)(PGA) is a promising chemically recyclable polymer...Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid)(PGA) is a promising chemically recyclable polymer, characterized by its seawater degradability and high mechanical strength. In this study, aliphatic polycarbonates were synthesized through melt polycondensation and subsequently copolymerized with glycolide(GL) to produce chemically recyclable PGA based triblock copolymers with well-defined structures. The properties of these copolymers, including their thermal properties, crystallization behavior, and mechanical performance, can be effectively adjusted by modifying the structure and content of the middle block. Furthermore, an in-depth investigation reveals that the pyrolysis process involves ester exchange, radical, and back-biting reactions. In addition, the high-efficiency "Monomer↔Copolymer" chemical recycling loop has been established, achieving a remarkable yield exceeding 88% along with a purity greater than 99%.展开更多
Conventional liquid electrolytes in lithium-ion batteries(LIBs)pose significant safety risks and interfacial instability,hindering the development of high-energy-density systems.Solid polymer electrolytes(SPEs),partic...Conventional liquid electrolytes in lithium-ion batteries(LIBs)pose significant safety risks and interfacial instability,hindering the development of high-energy-density systems.Solid polymer electrolytes(SPEs),particularly polyethylene oxide(PEO)-based systems,offer enhanced safety but suffer from low room-temperature ionic conductivity due to high crystallinity,alongside limitations such as poor lithium-ion transference numbers and dendrite growth.To address these challenges,this study develops a novel composite solid electrolyte(PSPH)by synthesizing a polystyrene-polyethylene oxide-polystyrene(PSPEO-PS)triblock copolymer and blending it with poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and lithium bis(trifluoromethylsulfonyl)imide(LiTFSI).The rigid PS segments suppress PEO crystallization,while PVDF-HFP enhances amorphous domain content,promotes LiTFSI dissociation via its high dielectric constant,and improves mechanical strength.The optimized PSPH composition(M_(w,PEO)=35 kg·mol^(-1),w_(PS)=15%,w_(PVDF-HFP)=30%)exhibits a high ionic conductivity of 1.05×10^(-4) S·cm^(-1)at 25℃,a Li^(+)transference number of 0.46,and an extended electrochemical stability window up to 4.8 V.PSPH demonstrates excellent thermal stability(decomposition onset at about 340℃),flexibility,and interfacial compatibility.LiFePO_(4)/PSPH/Li cells delivere a high discharge capacity of 163.7 mAh·g^(-1) at 0.1 C,with 96.2%capacity retention and 99.83%average coulombic efficiency after 200 cycles.Furthermore,Li/PSPH/Li symmetric cells exhibit stable cycling for over 1500 h at 0.05 mA·cm^(-2) with low overpotential(about 0.15 V).These results demonstrate that PSPH is a highly promising electrolyte for enhancing the safety and electrochemical performance of all-solid-state lithium-metal batteries(LMBs).展开更多
Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carbo...Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn（II） （n）, pH, background electrolyte, etc on the rejection rate （R） and permeate flux （J） were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn（II） with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength.展开更多
Three well-defined diblock copolymers ofpoly（methyl methacrylate-b-methacrylic acid） （P（MMA-b-MAA）） were synthesized using atom transfer radical polymerization method and varying poly（methacrylic acid） （PMAA...Three well-defined diblock copolymers ofpoly（methyl methacrylate-b-methacrylic acid） （P（MMA-b-MAA）） were synthesized using atom transfer radical polymerization method and varying poly（methacrylic acid） （PMAA） chain lengths. These copolymers were blended with PVC to fabricate porous membranes via phase inversion process. Membrane morphologies were observed by scanning electron microscopy （SEM）, and chemical composition changes of the membrane surfaces were measured by X-ray photoelectron spectroscopy （XPS）. Static and dynamic protein adsorption experiments were used to evaluate antifouling properties of the blend membranes. It was found that, the blend membranes containing longer PMAA arm length showed lower static protein adsorption, higher water permeation flux and better protein solution flux recovery.展开更多
Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,an...Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied.Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA.The impact strength of 50/10/40 PLA/MBS/PPCU blend(74.7 k J/m^2)was about 7.5 times higher than that of the neat PLA(10.8 k J/m^2),and the elongation at break of 50/10/40 PLA/MBS/PPCU blend(276.5%)was higher by about 45 times that of PLA(6.2%).The tear strength of PLA/MBS/PPCU films was 20 k N/m higher than that of PLA,and the elongation at break(MD/TD)of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%,whereas that of PLA was only 2.7%/3.0%.POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS.With increasing PPCU content from 5%to 20%,the density of spherulite nucleation increased and the size of crystalline particles decreased continuously,but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30%to 40%.The PLA/MBS/PPCU films exhibited excellent mechanical properties,which expanded the application range of these biodegradable films.展开更多
Poly （ethyleneglycol monomethylether） methacrylate （PEGMM）was synthesized by means of the reaction of methacrylyl chloride with sodium monomethylpolyethyleneglycoxide and was characterized by FTIR,;H-NMR,and ultra...Poly （ethyleneglycol monomethylether） methacrylate （PEGMM）was synthesized by means of the reaction of methacrylyl chloride with sodium monomethylpolyethyleneglycoxide and was characterized by FTIR,;H-NMR,and ultraviolet spectrometries. A series of poly （vinyl alcohol）-graft-PEGMM （PVA-g-PEGMM ）and methyl methacrylate-PEGMM copolymer （PMMA-PEGMM） were prepared and tested for antithrombogenicity in vitro. The results indicate that the antithrombogenicity of the copolymers basically increases with the increasing of the DP of polyoxyethylene （POE） chain and tends to a plateau after the DP around 114,i.e. the long chain structure of POE is favourable to the antithrombogenicityof its copolymers ;moreover, the extent of the improvement ofantithrombogenicity also relates to the PEGMM content of the copolymers and the kind of the matrix that the POE chains are located on. These results are consistent with the anticipation of the hypothesis of maintaining proteins normal conformations for blood compatible bioraaterials.展开更多
This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acr...This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.展开更多
Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as ...Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.展开更多
A carbon dioxide copolymer poly（urethane-amine） （PUA） was blended with poly（propylene carbonate） （PPC） in order to improve the toughness and flexibility of PPC without sacrificing other mechanical properties. ...A carbon dioxide copolymer poly（urethane-amine） （PUA） was blended with poly（propylene carbonate） （PPC） in order to improve the toughness and flexibility of PPC without sacrificing other mechanical properties. Compared with pure PPC, the PPC/PUA blend with 5 wt% PUA loading showed a 400% increase in elongation at break, whilst the corresponding yielding strength remained as high as 33.5 MPa and Young＇s modulus showed slightly decrease. The intermolecular hydrogen bonding interaction in PPC/PUA blends was comfirmed by FTIR, 2D IR and XPS spectra analysis, and finely dispersed particulate structure of PUA in PPC was observed in the SEM images, which provided good evidence for the toughening mechanism of PPC.展开更多
Poly（butylene terephthalate）-poly（tetramethylene glycol） （PBT-PTMG） copolymer is prepared with terephthalic acid （PTA） rather than its dimethyl ester （DMT） as starting material by a two-step melt polycondens...Poly（butylene terephthalate）-poly（tetramethylene glycol） （PBT-PTMG） copolymer is prepared with terephthalic acid （PTA） rather than its dimethyl ester （DMT） as starting material by a two-step melt polycondensation. This process includes the synthesis of PBT prepolymer from PTA with 1,4-butanediol （BDO） in the first step, followed by the synthesis of PBT-PTMG copolymer from PBT prepolymer with PTMG in the second step. The molecular weight, composition as well as thermal and mechanical properties of the products from the two-step melt polycondensation are compared with the properties of the PBT-PTMG from the traditional one-step melt polycondensation. When the PTMG content is low, there is only slight difference in molecular weight, composition, thermal and mechanical properties among PBT-PTMG copolymers obtained from these two methods. However, when the PTMG content is high, only the two-step strategy is able to give high molecular weight products, and the products have comparable thermal and mechanical properties with those from traditional one-step strategy using DMT as starting material.展开更多
The morphology and mechanical properties of poly（ethylene-octene） copolymers （POE） obtained by dynamic packing injection molding were investigated by mechanical tests, differential scanning calorimetry （DSC）, fo...The morphology and mechanical properties of poly（ethylene-octene） copolymers （POE） obtained by dynamic packing injection molding were investigated by mechanical tests, differential scanning calorimetry （DSC）, fourier transform infrared spectroscopy （FT-IR） and scanning electron microscopy （SEM）. The mechanical tests found that only POE with low octene content and high molecular weight show apparent response for external shear field. Further investigation has been done by DSC, FT-IR, and SEM in order to make clear the reason of that phenomenon. Finally, the hypothetical mechanism of POE microstructure formation under shear field has been proposed. For POE with low octene content and high molecular weight, orientation degree and mechanical properties both increase substantially under shear field. For POE with low octene content and low molecular weight, orientation degree and crystallinity increase under shear field, but it is not dramatically benefit for the mechanical properties. For POE with high octene content and high molecular weight, the shear field has little effect on the morphology and mechanical properties.展开更多
Porous PVDF blend membranes with good hydrophilicity and a symmetric structure were prepared by the phase inversion method using amphiphilic brush-like copolymers, P（MMA-r-PEGMA）, as hydrophilic additive and triethy...Porous PVDF blend membranes with good hydrophilicity and a symmetric structure were prepared by the phase inversion method using amphiphilic brush-like copolymers, P（MMA-r-PEGMA）, as hydrophilic additive and triethylphosphate （TEP） as solvent. P（MMA-r-PEGMA） was synthesized by radical polymerization in TEP. Then the obtained amphiphilic copolymer solution was mixed with PVDF and TEP to prepare the dope solution. The effects of P（MMA-r-PEGMA） content and coagulation composition on membrane morphologies were investigated using scanning electron microscopy （SEM）. The results demonstrated that, even blended with amphiphilic copolymers, a symmetric structure can be formed. Hollow fiber membranes with a mainly symmetric structure were also fabricated. The dry hollow fiber membranes showed good hydrophilicity, high flux and good rejection performance because of their hydrophilic surface and pores wall.展开更多
Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chit...Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chitosan, (2) poly (D,L-lactic acid)(PLA) with low molecular weight can be linked to the amino group by coupling activated PLA to trimethylsilyl-chitosan. Two graft copolymers had hydrophilic-hydrophobic character and can be applied as carriers for drug delivery.展开更多
Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macr...Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly（ethylene glycol） monomethyl ether （PEG）. The copolymers were obtained via the ATRP ofN-isopropylacrylamide （NIPAM） at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O （v/v = 3：1） mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography （GPC） and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions （PDI 〈 1.15）. Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry （DSC）. As a result, the phase transition temperature of PEG45-b-（PNIPAM55）2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition.展开更多
Novel amphiphilic fluorescent graft copolymer （PVP-PyAHy） was successfully synthesized by the free radical copolymerization of hydrophobic monomer N-（1-pyrenebutyryl）-N＇-acryloyl hydrazide （PyAHy） with hydrophi...Novel amphiphilic fluorescent graft copolymer （PVP-PyAHy） was successfully synthesized by the free radical copolymerization of hydrophobic monomer N-（1-pyrenebutyryl）-N＇-acryloyl hydrazide （PyAHy） with hydrophilic precursor polymers of vinyl-functionalized poly（N-vinylpyrrolidone） （PVP） in DMF. The copolymer is amphiphilic and has intrinsic fluorescence. FT-IR, ^1H-NMR, TEM, gel permeation chromatography-multi-angle laser light scattering, UV-Vis spectroscopy and fluorescence spectroscopy were used to characterize this copolymer. The TEM observation shows that the copolymer PVP-PyAHy forms micelles in aqueous solution. Results of fluorometric measurements illustrate that the critical micelle concentration （CMC） value of PVP-PyAHy in aqueous solution is about 0.90 mg/mL. To examine the encapsulation ability of the copolymer in aqueous media, methyl yellow was employed as a model hydrophobic agent. The loading level of the polymer to methyl yellow is 8.8 mg/g. The cytotoxicity assays for Madin Darby Canine Kidney （MDCK） cells shows good biocompatibility of PVP-PyAHy in vitro. These results suggest the potential of this copolymer PVP-PyAHy as drugs delivery carrier and fluorescent tracer.展开更多
The hydrophilic, macroporous and beaded ternary copolymer of glycidyl methacrylate （GMA）/methacrylamide（MA）/N,N＇-methylene-bis（acrylamide）（MBAA）was synthesized using the industrial agents by inverse suspensio...The hydrophilic, macroporous and beaded ternary copolymer of glycidyl methacrylate （GMA）/methacrylamide（MA）/N,N＇-methylene-bis（acrylamide）（MBAA）was synthesized using the industrial agents by inverse suspension polymerization. The apparent activity of the immobilized penicillin G acylase reached 1096 IU/g for hydrolysis penicillin G on the beads with diameter of 0.11-0.13 ram, and it changed hardly after 50 cycles. It can be expected to be a good potential in industrial application,展开更多
The effect of the architecture of poly(ethylene glycol)/poly(L-lactide)(PEG/PLLA) block copolymers on the non-isothermal crystallization behaviors of PLLA blocks was investigated by differential scanning calorimetry(D...The effect of the architecture of poly(ethylene glycol)/poly(L-lactide)(PEG/PLLA) block copolymers on the non-isothermal crystallization behaviors of PLLA blocks was investigated by differential scanning calorimetry(DSC) and wide angle X-ray diffraction(WAXD). 1-Arm MPEG-b-PLLA and 4-arm PEG-b-PLLA(4PEG-b-PLLA) were synthesized by the ring-opening polymerization of Llactide in the presence of poly(ethylene glycol) methyl ether(MPEG) and 4-arm poly(ethylene glycol)(4PEG). 4-Arm PLLA-b-MPEG(4PLLA-b-PEG) was synthesized by coupling 4-arm PLLA and MPEG. The WAXD results indicated that the crystalline structure of PLLA blocks did not alter due to the different chain architectures. The average values of Avrami index(ˉn) were all above 4, which indicated that the nucleation mechanism of PLLA blocks was heterogeneous nucleation, regardless of the architectures. The overall crystallization rates were decreased markedly as following: MPEG-b-PLLA > 4PEG-b-PLLA > 4PLLA-b-PEG, ascribed to the different confinement by PEG blocks and to the steric hindrance of chain architectures. Therefore, the crystallization of PLLA blocks became more difficult and the crystallization activation energy of the PLLA blocks increased due to the confinement of chain architectures.展开更多
Chitosan-graft-poly（lactic acid） （CS-g-PLA） copolymer was synthesized through emulsion self-assembly in a water-in-oil （W/O） microemulsion. The water phase was composed of CS aqueous solution, while the oil phas...Chitosan-graft-poly（lactic acid） （CS-g-PLA） copolymer was synthesized through emulsion self-assembly in a water-in-oil （W/O） microemulsion. The water phase was composed of CS aqueous solution, while the oil phase was made up of PLA in chloroform. The W/O microemulsion was fabricated in the presence of surfactant span-80 and the self-assembly was performed between PLA and CS under the effect of N-（3-dimethylaminopropyl）-N＇ethylcarbodiimide hydrochloride （EDC＇HCI）. FTIR and IH-NMR analysis indicated PLA was grafted onto the backbone of CS via the reaction between the carboxyl groups in PLA and the amino groups in CS. 1H-NMR characterization further revealed the grafting content of PLA was 16%. The obtained CS-g-PLA could self-assemble to form micelles, their size distributed in the range of 125-375 nm with average diameter of 142 nm. The present design integrates the favorable biological properties of CS and the excellent mechanical properties of PLA, which makes CS-g-PLA copolymer a promising candidate as a carrier for targeted bioactive molecules delivery.展开更多
Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile...Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile） （PPEN） in the presence of chlorobenzcne/N-methyl pyrrolidone （NMP） as solvents. The products were characterized by FTIR, ^1H NMR and gel permeation chromatography. Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.展开更多
基金the National Natural Science Foundation of China(Nos.21722402 and 21674015).
文摘Copolymerization is a commonly employed method for optimizing the properties of polymer materials.Incorporating ether segments into polyesters main chain to obtain polyether-polyester copolymers is an effective strategy to realize the integration of multiple properties of polyester and polyether,and to develop more high-performance,multi-purpose polymer materials.Herein,the synthesis of poly(ether-ester)s is accessible by employing the biphenyl-linked heterodinuclear salen Cr-AI complex in the presence of PPNCI for the copolymerization of epoxides and£-caprolactone(CL).Monitoring the copolymerization process reveals that catalyst 1 exhibited good performance for the copolymerization of epoxides and CL,affording copolymers with a gradient sequence structure.The dynamic thermomechanical analysis(DMA)study indicates the obtained poly(ether-ester)s possess enhanced flexibility compared with the block copolymers or blend of PPO and PCL homopolymers with the same ratio.This study provides a theoretical basis for the preparation of high-performance polymer materials.
基金financially supported by the National Key R&D Program of China(No.2021YFB3801901)the Institutional Research Fund from Sichuan University(No.2020SCUNL205)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Higher Education Discipline Innovation Project(No.B20001)。
文摘Polymers that exhibit both biodegradability and chemical recyclability offer a promising solution to environmental pollution and resource scarcity. Poly(glycolic acid)(PGA) is a promising chemically recyclable polymer, characterized by its seawater degradability and high mechanical strength. In this study, aliphatic polycarbonates were synthesized through melt polycondensation and subsequently copolymerized with glycolide(GL) to produce chemically recyclable PGA based triblock copolymers with well-defined structures. The properties of these copolymers, including their thermal properties, crystallization behavior, and mechanical performance, can be effectively adjusted by modifying the structure and content of the middle block. Furthermore, an in-depth investigation reveals that the pyrolysis process involves ester exchange, radical, and back-biting reactions. In addition, the high-efficiency "Monomer↔Copolymer" chemical recycling loop has been established, achieving a remarkable yield exceeding 88% along with a purity greater than 99%.
基金supported by the 2024 Capital Construction Funds within the Provincial Budget of Jilin Provincial Development and Reform Commission[2024C018-2].
文摘Conventional liquid electrolytes in lithium-ion batteries(LIBs)pose significant safety risks and interfacial instability,hindering the development of high-energy-density systems.Solid polymer electrolytes(SPEs),particularly polyethylene oxide(PEO)-based systems,offer enhanced safety but suffer from low room-temperature ionic conductivity due to high crystallinity,alongside limitations such as poor lithium-ion transference numbers and dendrite growth.To address these challenges,this study develops a novel composite solid electrolyte(PSPH)by synthesizing a polystyrene-polyethylene oxide-polystyrene(PSPEO-PS)triblock copolymer and blending it with poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and lithium bis(trifluoromethylsulfonyl)imide(LiTFSI).The rigid PS segments suppress PEO crystallization,while PVDF-HFP enhances amorphous domain content,promotes LiTFSI dissociation via its high dielectric constant,and improves mechanical strength.The optimized PSPH composition(M_(w,PEO)=35 kg·mol^(-1),w_(PS)=15%,w_(PVDF-HFP)=30%)exhibits a high ionic conductivity of 1.05×10^(-4) S·cm^(-1)at 25℃,a Li^(+)transference number of 0.46,and an extended electrochemical stability window up to 4.8 V.PSPH demonstrates excellent thermal stability(decomposition onset at about 340℃),flexibility,and interfacial compatibility.LiFePO_(4)/PSPH/Li cells delivere a high discharge capacity of 163.7 mAh·g^(-1) at 0.1 C,with 96.2%capacity retention and 99.83%average coulombic efficiency after 200 cycles.Furthermore,Li/PSPH/Li symmetric cells exhibit stable cycling for over 1500 h at 0.05 mA·cm^(-2) with low overpotential(about 0.15 V).These results demonstrate that PSPH is a highly promising electrolyte for enhancing the safety and electrochemical performance of all-solid-state lithium-metal batteries(LMBs).
基金Project (21176264) supported by the National Natural Science Foundation of ChinaProject (11JJ2010) supported by Hunan Provincial Natural Science Foundation of ChinaProject (LC13076) supported by Undergraduate Innovation Foundation of Central South University,China
文摘Copolymer of maleic acid and acrylic acid （PMA-100）, combining with polyvinyl butyral （PVB） ultrafiltration membrane was used for the removal of Mn（II） from waste water by complexation-ultrafiltration. The carboxylic group content of PMA-100 and the rate of complexation reaction were measured. Effects of the mass ratio of PMA-100 to Mn（II） （n）, pH, background electrolyte, etc on the rejection rate （R） and permeate flux （J） were investigated. The results show that carboxylic group content of PMA-100 is 9.5 mmol/g. The complexation of Mn（II） with PMA-100 is rapid and completed within 5 min at pH 6.0. Both R and J increase with pH increasing in the range of 2.5-7.0, and R increases with the increase of n at pH 6.0 while J is little affected. The background electrolyte leads to the decrease of R, and CaCl2 has much greater effect on R than NaCl at the same ionic strength.
基金supported by the National 973 Program(No.2009CB623402)the National Natural Science Foundation of China(No.20974094)
文摘Three well-defined diblock copolymers ofpoly（methyl methacrylate-b-methacrylic acid） （P（MMA-b-MAA）） were synthesized using atom transfer radical polymerization method and varying poly（methacrylic acid） （PMAA） chain lengths. These copolymers were blended with PVC to fabricate porous membranes via phase inversion process. Membrane morphologies were observed by scanning electron microscopy （SEM）, and chemical composition changes of the membrane surfaces were measured by X-ray photoelectron spectroscopy （XPS）. Static and dynamic protein adsorption experiments were used to evaluate antifouling properties of the blend membranes. It was found that, the blend membranes containing longer PMAA arm length showed lower static protein adsorption, higher water permeation flux and better protein solution flux recovery.
基金financially supported by the National Science Foundation of Zhejiang Province of China (No. LQY19B040001)the fund of Science and Technology Bureau of Jilin Province of China (No. 20170204012SF)+1 种基金the Program of Changchun Science and Technology Bureau (No. 16CX23)National Key Research and Development Program of China (No. 2016YFC0501402-5)
文摘Polylactide(PLA),methyl methacrylate-butadiene-styrene copolymer(MBS),and poly(propylene carbonate)polyurethane(PPCU)were blended and subjected to blown film process.The rheological,mechanical,morphological,thermal,and crystalline properties of the PLA/MBS/PPCU ternary blends and the mechanical properties of the resulting films were studied.Results of mechanical test showed that PPCU and MBS could synergistically toughen PLA.The impact strength of 50/10/40 PLA/MBS/PPCU blend(74.7 k J/m^2)was about 7.5 times higher than that of the neat PLA(10.8 k J/m^2),and the elongation at break of 50/10/40 PLA/MBS/PPCU blend(276.5%)was higher by about 45 times that of PLA(6.2%).The tear strength of PLA/MBS/PPCU films was 20 k N/m higher than that of PLA,and the elongation at break(MD/TD)of 50/10/40 PLA/MBS/PPCU films was 271.1%/222.3%,whereas that of PLA was only 2.7%/3.0%.POM observations displayed that the density of spherulite nucleation increased and the size of crystalline particles decreased with the addition of MBS.With increasing PPCU content from 5%to 20%,the density of spherulite nucleation increased and the size of crystalline particles decreased continuously,but the nucleation density of spherulites was slightly lowered with increasing PPCU content from 30%to 40%.The PLA/MBS/PPCU films exhibited excellent mechanical properties,which expanded the application range of these biodegradable films.
文摘Poly （ethyleneglycol monomethylether） methacrylate （PEGMM）was synthesized by means of the reaction of methacrylyl chloride with sodium monomethylpolyethyleneglycoxide and was characterized by FTIR,;H-NMR,and ultraviolet spectrometries. A series of poly （vinyl alcohol）-graft-PEGMM （PVA-g-PEGMM ）and methyl methacrylate-PEGMM copolymer （PMMA-PEGMM） were prepared and tested for antithrombogenicity in vitro. The results indicate that the antithrombogenicity of the copolymers basically increases with the increasing of the DP of polyoxyethylene （POE） chain and tends to a plateau after the DP around 114,i.e. the long chain structure of POE is favourable to the antithrombogenicityof its copolymers ;moreover, the extent of the improvement ofantithrombogenicity also relates to the PEGMM content of the copolymers and the kind of the matrix that the POE chains are located on. These results are consistent with the anticipation of the hypothesis of maintaining proteins normal conformations for blood compatible bioraaterials.
基金the National Metallurgical Laboratory,Jamshedpur for their kind support
文摘This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin(AP), poly acrylic acid(PAA), and a graft copolymer(AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction(XRD) and electron probe microanalysis(EPMA) techniques.
基金The authors are Indebted to the National Basic Science Rescarch and Development Grants(973)(No.1999054306).
文摘Poly (L-lactide)-poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. These copolymers presented special properties, such as better miscibility between the two components, low crystallinity and better hydrophilicity, which can be modulated by adjusting the block lengths of the two components.
文摘A carbon dioxide copolymer poly（urethane-amine） （PUA） was blended with poly（propylene carbonate） （PPC） in order to improve the toughness and flexibility of PPC without sacrificing other mechanical properties. Compared with pure PPC, the PPC/PUA blend with 5 wt% PUA loading showed a 400% increase in elongation at break, whilst the corresponding yielding strength remained as high as 33.5 MPa and Young＇s modulus showed slightly decrease. The intermolecular hydrogen bonding interaction in PPC/PUA blends was comfirmed by FTIR, 2D IR and XPS spectra analysis, and finely dispersed particulate structure of PUA in PPC was observed in the SEM images, which provided good evidence for the toughening mechanism of PPC.
基金financially supported by the Key Research Program of the Chinese Academy of Sciences(No.KGZD-EW-606-16)Ningbo Key Lab of Polymer Materials(No.2010A22001)Ningbo Natural Science Foundation(Nos.2013A610025,2013A610023 and 2014A610135)
文摘Poly（butylene terephthalate）-poly（tetramethylene glycol） （PBT-PTMG） copolymer is prepared with terephthalic acid （PTA） rather than its dimethyl ester （DMT） as starting material by a two-step melt polycondensation. This process includes the synthesis of PBT prepolymer from PTA with 1,4-butanediol （BDO） in the first step, followed by the synthesis of PBT-PTMG copolymer from PBT prepolymer with PTMG in the second step. The molecular weight, composition as well as thermal and mechanical properties of the products from the two-step melt polycondensation are compared with the properties of the PBT-PTMG from the traditional one-step melt polycondensation. When the PTMG content is low, there is only slight difference in molecular weight, composition, thermal and mechanical properties among PBT-PTMG copolymers obtained from these two methods. However, when the PTMG content is high, only the two-step strategy is able to give high molecular weight products, and the products have comparable thermal and mechanical properties with those from traditional one-step strategy using DMT as starting material.
基金supported by the special funds for Major State Basic Research Projects of China (No.2011CB606006)Program for the New-Century Excellent Talents of Ministry of Education of China(NCET-10- 0580)
文摘The morphology and mechanical properties of poly（ethylene-octene） copolymers （POE） obtained by dynamic packing injection molding were investigated by mechanical tests, differential scanning calorimetry （DSC）, fourier transform infrared spectroscopy （FT-IR） and scanning electron microscopy （SEM）. The mechanical tests found that only POE with low octene content and high molecular weight show apparent response for external shear field. Further investigation has been done by DSC, FT-IR, and SEM in order to make clear the reason of that phenomenon. Finally, the hypothetical mechanism of POE microstructure formation under shear field has been proposed. For POE with low octene content and high molecular weight, orientation degree and mechanical properties both increase substantially under shear field. For POE with low octene content and low molecular weight, orientation degree and crystallinity increase under shear field, but it is not dramatically benefit for the mechanical properties. For POE with high octene content and high molecular weight, the shear field has little effect on the morphology and mechanical properties.
基金financially supported by the National Natural Science Foundation of China(No.20974094)National 973 Program(No.2009CB623402)+1 种基金Key Innovation Team for Science and Technology of Zhejiang Province,China(No.2009R50047)Postdoctoral Science Foundation funded project of Zhejiang Province,China(No.Bsh1202045)
文摘Porous PVDF blend membranes with good hydrophilicity and a symmetric structure were prepared by the phase inversion method using amphiphilic brush-like copolymers, P（MMA-r-PEGMA）, as hydrophilic additive and triethylphosphate （TEP） as solvent. P（MMA-r-PEGMA） was synthesized by radical polymerization in TEP. Then the obtained amphiphilic copolymer solution was mixed with PVDF and TEP to prepare the dope solution. The effects of P（MMA-r-PEGMA） content and coagulation composition on membrane morphologies were investigated using scanning electron microscopy （SEM）. The results demonstrated that, even blended with amphiphilic copolymers, a symmetric structure can be formed. Hollow fiber membranes with a mainly symmetric structure were also fabricated. The dry hollow fiber membranes showed good hydrophilicity, high flux and good rejection performance because of their hydrophilic surface and pores wall.
文摘Biodegradable chitosan-g-poly (D, L-lactic acid) copolymers were prepared via two methods. (1) The lactide was grafted onto hydroxyl groups of chitosan by using macromolecular initiator sodium of trimethylsilyl-chitosan, (2) poly (D,L-lactic acid)(PLA) with low molecular weight can be linked to the amino group by coupling activated PLA to trimethylsilyl-chitosan. Two graft copolymers had hydrophilic-hydrophobic character and can be applied as carriers for drug delivery.
基金support from the National Natural Science Foundation of China(No. 20134020)the Visiting Scholar Project of Shandong Province of China(No.20081001)the Science Research Fund of Shandong Jiaotong University of China(No.Z200802)
文摘Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly（ethylene glycol） monomethyl ether （PEG）. The copolymers were obtained via the ATRP ofN-isopropylacrylamide （NIPAM） at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O （v/v = 3：1） mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography （GPC） and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions （PDI 〈 1.15）. Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry （DSC）. As a result, the phase transition temperature of PEG45-b-（PNIPAM55）2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition.
基金This work was supported by the National Natural Science Foundation of China (No. 20474044).
文摘Novel amphiphilic fluorescent graft copolymer （PVP-PyAHy） was successfully synthesized by the free radical copolymerization of hydrophobic monomer N-（1-pyrenebutyryl）-N＇-acryloyl hydrazide （PyAHy） with hydrophilic precursor polymers of vinyl-functionalized poly（N-vinylpyrrolidone） （PVP） in DMF. The copolymer is amphiphilic and has intrinsic fluorescence. FT-IR, ^1H-NMR, TEM, gel permeation chromatography-multi-angle laser light scattering, UV-Vis spectroscopy and fluorescence spectroscopy were used to characterize this copolymer. The TEM observation shows that the copolymer PVP-PyAHy forms micelles in aqueous solution. Results of fluorometric measurements illustrate that the critical micelle concentration （CMC） value of PVP-PyAHy in aqueous solution is about 0.90 mg/mL. To examine the encapsulation ability of the copolymer in aqueous media, methyl yellow was employed as a model hydrophobic agent. The loading level of the polymer to methyl yellow is 8.8 mg/g. The cytotoxicity assays for Madin Darby Canine Kidney （MDCK） cells shows good biocompatibility of PVP-PyAHy in vitro. These results suggest the potential of this copolymer PVP-PyAHy as drugs delivery carrier and fluorescent tracer.
基金supported by the National Natural Science Foundation of China(No.20564002)the State Key Program of Fundamental Research(No.2004CCA05900).
文摘The hydrophilic, macroporous and beaded ternary copolymer of glycidyl methacrylate （GMA）/methacrylamide（MA）/N,N＇-methylene-bis（acrylamide）（MBAA）was synthesized using the industrial agents by inverse suspension polymerization. The apparent activity of the immobilized penicillin G acylase reached 1096 IU/g for hydrolysis penicillin G on the beads with diameter of 0.11-0.13 ram, and it changed hardly after 50 cycles. It can be expected to be a good potential in industrial application,
基金financially supported by the National Natural Science Foundation of China(Nos.51303176,51873209,51573178,and 51773194)the National Key Research and Development Program of China(No.2016YFB0302500)
文摘The effect of the architecture of poly(ethylene glycol)/poly(L-lactide)(PEG/PLLA) block copolymers on the non-isothermal crystallization behaviors of PLLA blocks was investigated by differential scanning calorimetry(DSC) and wide angle X-ray diffraction(WAXD). 1-Arm MPEG-b-PLLA and 4-arm PEG-b-PLLA(4PEG-b-PLLA) were synthesized by the ring-opening polymerization of Llactide in the presence of poly(ethylene glycol) methyl ether(MPEG) and 4-arm poly(ethylene glycol)(4PEG). 4-Arm PLLA-b-MPEG(4PLLA-b-PEG) was synthesized by coupling 4-arm PLLA and MPEG. The WAXD results indicated that the crystalline structure of PLLA blocks did not alter due to the different chain architectures. The average values of Avrami index(ˉn) were all above 4, which indicated that the nucleation mechanism of PLLA blocks was heterogeneous nucleation, regardless of the architectures. The overall crystallization rates were decreased markedly as following: MPEG-b-PLLA > 4PEG-b-PLLA > 4PLLA-b-PEG, ascribed to the different confinement by PEG blocks and to the steric hindrance of chain architectures. Therefore, the crystallization of PLLA blocks became more difficult and the crystallization activation energy of the PLLA blocks increased due to the confinement of chain architectures.
基金financially supported by the National Natural Science Foundation of China(Nos.11272038,50803032,11032012,10925208,11202017 and 11120101001)the Fundamental Research Funds for the Central Universities(No.YWF-13-T-RSC-024)+2 种基金the 111 Project(No.B13003)the International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology of Chinathe Program of Pearl River Young Talents of Science and Technology in Guangzhou,China(No.2013Z2200010)
文摘Chitosan-graft-poly（lactic acid） （CS-g-PLA） copolymer was synthesized through emulsion self-assembly in a water-in-oil （W/O） microemulsion. The water phase was composed of CS aqueous solution, while the oil phase was made up of PLA in chloroform. The W/O microemulsion was fabricated in the presence of surfactant span-80 and the self-assembly was performed between PLA and CS under the effect of N-（3-dimethylaminopropyl）-N＇ethylcarbodiimide hydrochloride （EDC＇HCI）. FTIR and IH-NMR analysis indicated PLA was grafted onto the backbone of CS via the reaction between the carboxyl groups in PLA and the amino groups in CS. 1H-NMR characterization further revealed the grafting content of PLA was 16%. The obtained CS-g-PLA could self-assemble to form micelles, their size distributed in the range of 125-375 nm with average diameter of 142 nm. The present design integrates the favorable biological properties of CS and the excellent mechanical properties of PLA, which makes CS-g-PLA copolymer a promising candidate as a carrier for targeted bioactive molecules delivery.
文摘Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile） （PPEN） in the presence of chlorobenzcne/N-methyl pyrrolidone （NMP） as solvents. The products were characterized by FTIR, ^1H NMR and gel permeation chromatography. Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.
