High-energy density lithium-ion batteries(LIBs)with layered high-nickel oxide cathodes(LiNi_(x)Co_(y)Mn_(1-x-y)O_(2),x≥0.8)show great promise in consumer electronics and vehicular applications.However,LiNi_(x)Co_(y)M...High-energy density lithium-ion batteries(LIBs)with layered high-nickel oxide cathodes(LiNi_(x)Co_(y)Mn_(1-x-y)O_(2),x≥0.8)show great promise in consumer electronics and vehicular applications.However,LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)faces challenges related to capacity decay caused by residual alkalis owing to high sensitivity to air.To address this issue,we propose a hazardous substances upcycling method that fundamentally mitigates alkali content and concurrently induces the emergence of an anti-air-sensitive layer on the cathode surface.Through the neutralization of polyacrylic acid(PAA)with residual alkalis and then coupling it with 3-aminopropyl triethoxysilane(KH550),a stable and ion-conductive cross-linked polymer layer is in situ integrated into the LiNi_(0.89)Co_(0.06)Mn_(0.05)O_(2)(NCM)cathode.Our characterization and measurements demonstrate its effectiveness.The NCM material exhibits impressive cycling performance,retaining 88.4%of its capacity after 200 cycles at 5 C and achieving an extraordinary specific capacity of 170.0 mA h g^(-1) at 10 C.Importantly,this layer on the NCM efficiently suppresses unfavorable phase transitions,severe electrolyte degradation,and CO_(2)gas evolution,while maintaining commendable resistance to air exposure.This surface modification strategy shows widespread potential for creating air-stable LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)cathodes,thereby advancing high-performance LIBs.展开更多
The effects of different cation concentrations and types on rheological property and stability of Guar, Xanthan, and Partially Hydrolyzed Polyacrylamide(HPAM) cross-linked gels were analyzed through experiments. Also,...The effects of different cation concentrations and types on rheological property and stability of Guar, Xanthan, and Partially Hydrolyzed Polyacrylamide(HPAM) cross-linked gels were analyzed through experiments. Also, a new approach was developed to reduce the negative effects of cation by application of multi-walled carbon nano-tubes(MWCNTs). The presence of cations in cross-linked gel system will reduce the viscosity of gel, the higher the cation concentration is, the lower the viscosity will be. The bivalent cation has a greater viscosity reduction effect on gel than monovalent cation. The stability of cross-linked gels is worse with cations, this situation becomes more serious under higher salinity. MWCNTs were added to HPAM gel, cross-linked by(3-Aminopropyl) triethoxysilane(APTES), they surrounded cations and removed them from polymers and reduced the reaction possibility. This method enhances the viscosity and breakdown pressure of cross-linked gels, improves the stability of HPAM cross-linked gel under different operating conditions, and can be applied to related drilling projects.展开更多
Performance characteristics of partially hydrolyzed polyacrylamide (HPAM) and cross- linked polymer (CLP, Cr^3+ as the cross linker) solutions have been investigated. A Brookfield viscometer, rheometer, dynamic l...Performance characteristics of partially hydrolyzed polyacrylamide (HPAM) and cross- linked polymer (CLP, Cr^3+ as the cross linker) solutions have been investigated. A Brookfield viscometer, rheometer, dynamic light scattering system, and core flow device have been used to measure the viscosity, viscoelasticity, polymer coil dimensions, molecular configuration, flow characteristics, and profile modification. The results show that, under conditions of high salinity and low HPAM and Cr^3+ concentrations, cross-linking mainly occurred between different chains of the same HPAM molecule in the presence of Cr^3+, and a cross-linked polymer (CLP) system with a local network structure was formed. Compared with an HPAM solution of the same concentration, the apparent viscosity of the CLP solution increased slightly or remained almost unchanged, but its viscoelasticity (namely storage modulus, loss modulus, and first normal stress difference) increased, and the resistance coefficient and residual resistance coefficient increased significantly. This indicates that the CLP solution exhibits a strong capability to divert the sequentially injected polymer flood from high-permeability zones to low- permeability zones in a reservoir. Under the same HPAM concentration conditions, the dimensions of polymer coils in the CLP solution increased slightly compared with the dimensions of polymer coils in HPAM solution, which were smaller than the rock pores, indicating that the cross-linked polymer solution was well adapted to reservoir rocks. Core flood experiments show that at the same cost of reagent, the oil recovery by CLP injection (HPAM-1, Cr^3+ as the cross linker) is 3.1% to 5.2% higher than that by HPAM- 2 injection.展开更多
Solid polymer electrolytes(SPEs)have become increasingly important in advanced lithium-ion batteries(LIBs)due to their improved safety and mechanical properties compared to organic liquid electrolytes.Cross-linked pol...Solid polymer electrolytes(SPEs)have become increasingly important in advanced lithium-ion batteries(LIBs)due to their improved safety and mechanical properties compared to organic liquid electrolytes.Cross-linked polymers have the potential to further improve the mechanical property without trading off Li-ion conductivity.In this study,focusing on a recently developed cross-linked SPE,i.e.,the one based on poly(vinylene carbonate)-poly(ethylene oxide)cross-linked network(PVCN),we used solid-state nuclear magnetic resonance(NMR)techniques to investigate the fundamental interaction between the chain segments and Li ions,as well as the lithium-ion motion.By utilizing homonuclear/heteronuclear correlation,CP(cross-polarization)kinetics,and spin-lattice relaxation experiments,etc.,we revealed the structural characteristics and their relations to lithium-ion mobilities.It is found that the network formation prevents poly(ethylene oxide)chains from crystallization,which could create sufficient space for segmental tumbling and Li-ion co nductio n.As such,the mechanical property is greatly improved with even higher Li-ion mobilities compared to the poly(vinylene carbonate)or poly(ethylene oxide)based SPE analogues.展开更多
Lithium-metal anodes(LMAs)have been recognized as the ultimate anodes for next-generation batteries with high energy density,but stringent assembly-environment conditions derived from the poor moisture stability drama...Lithium-metal anodes(LMAs)have been recognized as the ultimate anodes for next-generation batteries with high energy density,but stringent assembly-environment conditions derived from the poor moisture stability dramatically hinder the transformation of LMAs from laboratory to industry.Herein,an in situ formed cross-linked polymer layer on LMAs is designed and constructed by a facile thiol-acrylate click chemistry reaction between poly(ethylene glycol)diacrylate(PEGDA)and the crosslinker containing multi thiol groups under UV irradiation.Owing to the hydrophobic nature of the layer,the treated LMAs demonstrate remarkable humid stability for more than 3 h in ambient air(70%relative humidity).The coating humid-resistant protective layer also possesses a dual-functional characterization as solid polymer electrolytes by introducing lithium bis(trifluoromethanesulfonyl)imide in the system in advance.The intimate contact between the polymer layer and LMAs reduces interfacial resistance in the assembled Li/LiFePO_(4)or Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)full cell effectively,and endows the cell with an outstanding cycle performance.展开更多
Serving as a promising alternative to liquid electrolyte in the application of portable and wearable devices,gel polymer electrolytes(GPEs)are expected to obtain more preferable properties rather than just be satisfie...Serving as a promising alternative to liquid electrolyte in the application of portable and wearable devices,gel polymer electrolytes(GPEs)are expected to obtain more preferable properties rather than just be satisfied with the merits of high safety and deformability.Here,an easy-operated method is employed to fabricate cross-linked composite polymer membranes used for GPEs assisted by UV irradiation,in which N-doped carbon quantum dots(N-CQDs)and TiO2are introduced as photocatalysts and additives to improve the performances of GPEs.Specifically,N-CQDs participate as a cross-linker to construct the inner porous structure,and TiO2nanoparticles serve as a stabilizer to improve the electrochemical stability of GPEs under high voltage(3.5 V).The excellent thermal and mechanical stability of the membrane fabricated in this work guarantee the safety of the supercapacitors(SCs).This GPE based SC not only exhibits prominent rate performance(105%capacitance retention at the current density of 40A g^(-1))and cyclic stability(85%at 1 A g^(-1)under 3.5 V after 20,000 cycles),but also displays remarkable energy density(42.88 Wh kg^(-1))with high power density(19.3 k W kg^(-1)).Moreover,the superior rate and cycling performances of the as-prepared GPE based flexible SCs under flat and bending state confirm the feasibility of its application in flexible energy storage devices.展开更多
The self-healing solid polymer electrolytes(SHSPEs)can spontaneously eliminate mechanical damages or micro-cracks generated during the assembly or operation of lithium-ion batteries(LIBs),significantly improving cycli...The self-healing solid polymer electrolytes(SHSPEs)can spontaneously eliminate mechanical damages or micro-cracks generated during the assembly or operation of lithium-ion batteries(LIBs),significantly improving cycling performance and extending service life of LIBs.Here,we report a novel cross-linked network SHSPE(PDDP)containing hydrogen bonds and dynamic disulfide bonds with excellent self-healing properties and nonflammability.The combination of hydrogen bonding between urea groups and the metathesis reaction of dynamic disulfide bonds endows PDDP with rapid self-healing capacity at 28°C without external stimulation.Furthermore,the addition of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMIMTFSI)improves the ionic conductivity(1.13×10^(−4)S cm^(−1)at 28°C)and non-flammability of PDDP.The assembled Li/PDDP/LiFePO_(4)cell exhibits excellent cycling performance with a discharge capacity of 137 mA h g^(−1)after 300 cycles at 0.2 C.More importantly,the self-healed PDDP can recover almost the same ionic conductivity and cycling performance as the original PDDP.展开更多
Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, thre...Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, three different physical states can be identified (viscous, skin effect and cross-linked state). Knowledge of the evolution of these states at each reaction time is essential to determine the open time for the adhe-sive industry and is generally obtained by a manual method. Automation of this moni-toring could avoid operator error and could be used for very long cross linking reac-tions or to screen a large number of catalysts. Thus, a contactless micro process tech-nology was developed to correlate these physical states with an optical technology, Raman spectroscopy, by monitoring the decrease in intensity of the Si-OCH<sub>3</sub> groups during chemical reactions. This online characterization method can also be used to compare the efficiencies of several catalysts for the cross-linking of silyl-modified polymers, using a minimum amount of chemical materials.展开更多
Insoluble β-cyclodextrin polymers were prepared from β-cyclodextrin(β-CD) using epichlorohydrin(EPI) as crosslinking agent under basic conditions.The polymers were characterized by Fourier Transform Infrared(FTIR),...Insoluble β-cyclodextrin polymers were prepared from β-cyclodextrin(β-CD) using epichlorohydrin(EPI) as crosslinking agent under basic conditions.The polymers were characterized by Fourier Transform Infrared(FTIR),Thermogravimetry(TG),X-ray diffraction(XRD) and TG-FTIR.The results demonstrated that the polym-erization between EPI and β-CD indeed occurred,and a number of CD rings were interconnected to form a three-dimensional network.Moreover,different factors influencing the polymerization,e.g.molar ratio of EPI to β-CD,the concentration of NaOH and reaction temperature,have been investigated.The polymer prepared under the optimal conditions(the molar ratio EPI:β-CD of 44,the NaOH concentration 50% in mass,and the temperature at 65 ℃) showed excellent thermal stability and insolubility in organic solvents or strong acid/base.In addition,the β-cyclodextrin polymers also presented high catalytic activity for aqueous oxidation of benzyl alcohol with hy-pochlorite as oxidant.展开更多
Ionic liquids functionalized β-cyclodextrin polymer, a mono-6-deoxy-6-(1,2-dimethylimida- zolium)-β-cyclodextrin iodide polymer (ILs-β-CDCP), was synthesized as a solid-phase adsorbent coupled with high-perform...Ionic liquids functionalized β-cyclodextrin polymer, a mono-6-deoxy-6-(1,2-dimethylimida- zolium)-β-cyclodextrin iodide polymer (ILs-β-CDCP), was synthesized as a solid-phase adsorbent coupled with high-performance liquid chromatography for separating or analyzing magnolol in drug samples. The results showed that magnolol was adsorbed rapidly on ILs-D-CDCP and eluted with methanol. Under the optimum conditions, preconcentration factor of the proposed method was 12. The linear range, limit of detection (LOD), correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.02-8.00 μg/mL, 1.9 ng/mL, 0.9992 and 2.76% (n=3, c=2.00 pg/mL), respectively. The interaction between 1Ls-])-CDCP and magnolol was studied through the inclusion constant, FTIR and TGA analysis. This proposed method has been successfully applied to the determination of magnolol in real samples.展开更多
Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge.Herein,we develop an efficient continuous adsorption process for recoveri...Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge.Herein,we develop an efficient continuous adsorption process for recovering aromatic compounds in wastewater from styrene monomer and propylene oxide coproduction(SMPO)plant.Based on our insight into the potential of bio-based porous materials for adsorption application,starch-graft-polystyrene(SPS)and aryl-modifiedβ-cyclodextrin(ACD)were prepared,and novel hypercrosslinked porous polymers combined SPS with ACD(HSPS-ACDs)were synthesized through external crosslinking approach.In a binary-component system,the best-performing one HSPS-ACD(H)with high ACD content and large specific surface area possessed superior capacities for the representative aromatic compounds,acetophenone(AP,2.81 mmol·g^(-1))and 1-phenylethanol(1-PE,1.35 mmol·g^(-1))compared with the previously reported materials.Further,the adsorption properties of aromatic compounds on HSPS-ACD(H)were investigated in batch mode.For practical application,continuous adsorption experiments were conducted in a HSPS-ACD(H)-packed fixed bed,where the target aromatic components in wastewater were effectively retained and further released by elution.Besides showing the reversible adsorption and efficient enrichment effect,the HSPS-ACD(H)-packed fixed bed also maintained great stability in multiple cycles.Moreover,quantum chemical calculations were performed to elucidate the potential mechanism of adsorption of AP and 1-PE onto HSPS-ACD(H).展开更多
Three series of amorphous copolymers containing azobenzene groups with various substituents and certain amounts of crosslinkable acrylic groups were prepared. The cross-linked polymer films were obtained by thermal po...Three series of amorphous copolymers containing azobenzene groups with various substituents and certain amounts of crosslinkable acrylic groups were prepared. The cross-linked polymer films were obtained by thermal polymerization of the acrylic groups in the copolymers, during which, by controlling the time of cross-linking reaction, the films can be made with different cross-linking degree (from 0 to 32%, which was monitored by FT-IR spectra measurement). Photo-induced alignment process of the films was performed under irradiation with linearly polarized light at 442 nm, and the effect of cross-linking degree on the photo-induced alignment rate was investigated. The dynamics of the photo-induced alignment was analyzed with biexponential curve fitting. The photo-induced alignment rate and the maximum transmittance of the films decreased because of the cross-linking. Furthermore, for the cross-linked samples, it was found that their saturated value of transmittances keep constant after repeated "writing" and "erasing" cycles. The findings reveal that the cross-linking of the film can effectively restrain the phototactic mass transport of azopolymer during irradiation by polarized light. The relationship between the cross-linking degree and the photo-induced alignment behavior of azopolymer is discussed in detail.展开更多
A new series of polymers comprising four terpolymers was synthesized via Mannich polycondensation of benzene1,4diamine,formaldehyde and piperazine by varying the benzene1,4diamine and piperazine ratio.The new polyamin...A new series of polymers comprising four terpolymers was synthesized via Mannich polycondensation of benzene1,4diamine,formaldehyde and piperazine by varying the benzene1,4diamine and piperazine ratio.The new polyamines(labeled Dipip)were characterized using 13C solidstate NMR,FTIR,TGA,DSC,XRD,SEM and EDX.The adsorptive performances of the synthesized polymers for Erichrome Black T(EBT)uptake from aqueous solution were investigated under batch process.Equilibrium,kinetic,and thermodynamic studies were conducted to determine the influence of different operational parameters of the adsorption process.The two most promising polymers among the series show an excellent EBT removal efficiency of~100%and~95%with high adsorption capacities of 775 mgg 1 and 917 mgg 1,respectively at a meager dosage of 5 mg.The sorption of EBT on the polymers was well described by RedlichPeterson&Langmuir model while the kinetic studies indicate that pseudosecond order model was followed.For the thermodynamic studies,the negative AG and positive AH values obtained suggest a spontaneity of the sorption process which was endothermic in nature.The results of reusability test of the resins were promising even at the fourth cycle,showcasing the potentials of the new polymers in dyes contaminated water treatment.展开更多
A novel cyclodextrin-containing polymer was prepared by graftingβ-cyclodextrin onto the backbone of poly(D,L-lactic acid)(PLA).First,mono(6-(2-aminoethyl)amino-6-deoxy)-β-cyclodextrin(β-CD-6-en)was prepared by sulf...A novel cyclodextrin-containing polymer was prepared by graftingβ-cyclodextrin onto the backbone of poly(D,L-lactic acid)(PLA).First,mono(6-(2-aminoethyl)amino-6-deoxy)-β-cyclodextrin(β-CD-6-en)was prepared by sulfonylation and amination ofβ-cyclodextrin and modified poly(D,L-lactic acid)(MPLA)was prepared by free radical polymerization of maleic anhydride and PLA.Then,grafting ofβ-cyclodextrin derivative to MPLA backbone was carried out by N-acylation reaction of MPLA andβ-CD-6-en in dimethyl formamide.The...展开更多
An appropriate amount of toluene 2,4-diisocyanate(TDI) was added into polyether([(CH2CH2O)13 CH2O]n/Li salt electrolyte to form a cross-linked network,with improving the film proces sability and thermal stability...An appropriate amount of toluene 2,4-diisocyanate(TDI) was added into polyether([(CH2CH2O)13 CH2O]n/Li salt electrolyte to form a cross-linked network,with improving the film proces sability and thermal stability.The relation between the structure and ioinc conductive properties of the cross-lined polyether electrolytes was investigated by means of Fourier transform infra-red spectroscopy(FTIR),differential scanning calorimetry(DSC),mechanical property and AC impedance spectroscopy.The electrolytes system is found to have two glass transitions,and it is found that the two Tgs increase with increasing salt concentration.At the some Li salt concentration,the conductivity of cross-liked polyether/LiN(CF3SO2)2 complex system is higher than that of LiClo4,At EO/Li=25:1(mol ratio),the former conductivity changes with temperature,while the later coincids with Arrhenius formula(σ=Ae^-Ea/RT).The cross-linked polyether/LiN(CF3 SO2)2 electrolyte exhibits the maximum σ=10^-4.75S/cm at 30℃.展开更多
Different proportions of β-cydodextrin and epichlorohydrin were used to prepare a group of β-cyclodextrin polymers. The relationship between the reaction extent and the molar ratios of reactants was discussed accord...Different proportions of β-cydodextrin and epichlorohydrin were used to prepare a group of β-cyclodextrin polymers. The relationship between the reaction extent and the molar ratios of reactants was discussed according to the results of ~1H-NMR, ^(13) C-NMR spectra and elemental analysis. Especially, high resolution ~1H-NMR spectra were usd for studying the reaction active sites and the extent of reaction. The solubility of oil soluble drugs in water was largely improved in the presence of water-soluble β-cyclodextrin polymer.展开更多
Lithium-ion batteries(LIBs)benefit from an effective electrolyte system design in both terms of their safety and energy storage capability.Herein,a series of precursor membranes with high porosity were produced using ...Lithium-ion batteries(LIBs)benefit from an effective electrolyte system design in both terms of their safety and energy storage capability.Herein,a series of precursor membranes with high porosity were produced using electrospinning technology by mixing PVDF and triblock copolymer(PS-PEO-PS),resulting in a porous structure with good interconnections,which facilitates the absorbency of a large amount of electrolyte and further increases the ionic conductivity of gel polymer electrolytes(GPEs).It has been demonstrated that post-cross-linking of the precursor membranes increa ses the rigidity of the nanofibers,which allows the polymer film to be dimensionally sta ble up to 260℃while maintaining superior electrochemical properties.The obtained cross-linked GPEs(CGPEs)showed high ionic conductivity up to 4.53×10^(-3)S·cm^(-1).With the CGPE-25,the assembled Li/LiFeP04 half cells exhibited good rate capability and maintained a capacity of 99.4%and a coulombic efficiency of99.3%at 0.1 C.These results suggest that the combination of electrospinning technique and post-cross-linking is an effective method to construct polymer electrolytes with high thermal stability and steadily decent electrochemical performance,particularly useful for Lithium-ion battery applications that require high-temperature usage.展开更多
Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin(CM-β-CD) modified Fe3O4 nanoparti...Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin(CM-β-CD) modified Fe3O4 nanoparticles inβ-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent.The morphology,structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy(TEM),Fourier transform infrared(FTIR) spectrometry,X-ray diffraction(XRD) measurement,thermogravimetric analysis(TGA) and Vibrating sample magnetometry (VSM),respectively.展开更多
The viscosity property of Cr^3+, Al^3+, and compound ion cross-linked polymer gel solution in the anaerobic and aerobic environment was investigated aiming at meeting the practical demand of the oil field. The visco...The viscosity property of Cr^3+, Al^3+, and compound ion cross-linked polymer gel solution in the anaerobic and aerobic environment was investigated aiming at meeting the practical demand of the oil field. The viscosity reserving effect after adding the biocide and the gelation in the anaerobic and aerobic environments was also studied in the paper. The results indicate that the viscosity of the cross-linked polymer gel solution caused by the water produced in aerobic environment is higher than that in anaerobic environment, and that the viscosity value of the cross-linked polymer gel solutions after adding biocides has improved to some extent and polymer gel has gelated well in anaerobic environment.展开更多
As two pivotal functional segments,triazine and porphyrin can be coupled to form a highly cross-linked conjugated polymer.Although the obtained conjugated polymers are almost insoluble in most solvents,a small amount ...As two pivotal functional segments,triazine and porphyrin can be coupled to form a highly cross-linked conjugated polymer.Although the obtained conjugated polymers are almost insoluble in most solvents,a small amount of protonic acid can cause the formation of a colloidal solution of polymers.The dissolution process has proved to be a surface charge effect induced by protonation of porphyrin units in the polymer framework.High-quality conjugated polymer films have been prepared on diverse substrates by solution drop-casting and then used for thermoelectric(TE)applications.The films exhibit remarkable TE performance with high Seebeck coefficients(−6650μV K^(−1))and electronic conductivities(0.042 S cm^(−1)),yielding a power factor of 185μW m^(−1) K^(−2),which,collectively,are the highest among all reported n-type organic TE materials.This work may pave the way for the design and development of solution-processed,cross-linked polymer films as promising TE materials.展开更多
基金supported by the National Natural Science Foundation of China(52162030)the Yunnan Major Scientific and Technological Projects(202202AG050003)+4 种基金the Key Research and Development Program of Yunnan Province(202103AA080019)the Scientific Research Foundation of Kunming University of Science and Technology(20220122)the Graduate Student Top Innovative Talent Program of Kunming University of Science and Technology(CA23107M139A)the Analysis and Testing Foundation of Kunming University of Science and Technology(2023T20220122)the Shenzhen Science and Technology Program(KCXST20221021111201003)。
文摘High-energy density lithium-ion batteries(LIBs)with layered high-nickel oxide cathodes(LiNi_(x)Co_(y)Mn_(1-x-y)O_(2),x≥0.8)show great promise in consumer electronics and vehicular applications.However,LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)faces challenges related to capacity decay caused by residual alkalis owing to high sensitivity to air.To address this issue,we propose a hazardous substances upcycling method that fundamentally mitigates alkali content and concurrently induces the emergence of an anti-air-sensitive layer on the cathode surface.Through the neutralization of polyacrylic acid(PAA)with residual alkalis and then coupling it with 3-aminopropyl triethoxysilane(KH550),a stable and ion-conductive cross-linked polymer layer is in situ integrated into the LiNi_(0.89)Co_(0.06)Mn_(0.05)O_(2)(NCM)cathode.Our characterization and measurements demonstrate its effectiveness.The NCM material exhibits impressive cycling performance,retaining 88.4%of its capacity after 200 cycles at 5 C and achieving an extraordinary specific capacity of 170.0 mA h g^(-1) at 10 C.Importantly,this layer on the NCM efficiently suppresses unfavorable phase transitions,severe electrolyte degradation,and CO_(2)gas evolution,while maintaining commendable resistance to air exposure.This surface modification strategy shows widespread potential for creating air-stable LiNi_(x)Co_(y)Mn_(1-x-y)O_(2)cathodes,thereby advancing high-performance LIBs.
文摘The effects of different cation concentrations and types on rheological property and stability of Guar, Xanthan, and Partially Hydrolyzed Polyacrylamide(HPAM) cross-linked gels were analyzed through experiments. Also, a new approach was developed to reduce the negative effects of cation by application of multi-walled carbon nano-tubes(MWCNTs). The presence of cations in cross-linked gel system will reduce the viscosity of gel, the higher the cation concentration is, the lower the viscosity will be. The bivalent cation has a greater viscosity reduction effect on gel than monovalent cation. The stability of cross-linked gels is worse with cations, this situation becomes more serious under higher salinity. MWCNTs were added to HPAM gel, cross-linked by(3-Aminopropyl) triethoxysilane(APTES), they surrounded cations and removed them from polymers and reduced the reaction possibility. This method enhances the viscosity and breakdown pressure of cross-linked gels, improves the stability of HPAM cross-linked gel under different operating conditions, and can be applied to related drilling projects.
基金financial support from the National Key Technology R&D Program in the 12th Five Year Plan of PetroChina (No: 2011ZX05010-003-02)the National Key Technology R&D Program in the 12th Five Year Plan of CNOOC (No: 2011ZX05024-04-05-03)
文摘Performance characteristics of partially hydrolyzed polyacrylamide (HPAM) and cross- linked polymer (CLP, Cr^3+ as the cross linker) solutions have been investigated. A Brookfield viscometer, rheometer, dynamic light scattering system, and core flow device have been used to measure the viscosity, viscoelasticity, polymer coil dimensions, molecular configuration, flow characteristics, and profile modification. The results show that, under conditions of high salinity and low HPAM and Cr^3+ concentrations, cross-linking mainly occurred between different chains of the same HPAM molecule in the presence of Cr^3+, and a cross-linked polymer (CLP) system with a local network structure was formed. Compared with an HPAM solution of the same concentration, the apparent viscosity of the CLP solution increased slightly or remained almost unchanged, but its viscoelasticity (namely storage modulus, loss modulus, and first normal stress difference) increased, and the resistance coefficient and residual resistance coefficient increased significantly. This indicates that the CLP solution exhibits a strong capability to divert the sequentially injected polymer flood from high-permeability zones to low- permeability zones in a reservoir. Under the same HPAM concentration conditions, the dimensions of polymer coils in the CLP solution increased slightly compared with the dimensions of polymer coils in HPAM solution, which were smaller than the rock pores, indicating that the cross-linked polymer solution was well adapted to reservoir rocks. Core flood experiments show that at the same cost of reagent, the oil recovery by CLP injection (HPAM-1, Cr^3+ as the cross linker) is 3.1% to 5.2% higher than that by HPAM- 2 injection.
基金financially supported by the National Natural Science Foundation of China(Grant No.22325405,22321002,22279153)Liaoning Revitalization Talents Program(XLYC1807207,XLYC2203134)DICP I202104。
文摘Solid polymer electrolytes(SPEs)have become increasingly important in advanced lithium-ion batteries(LIBs)due to their improved safety and mechanical properties compared to organic liquid electrolytes.Cross-linked polymers have the potential to further improve the mechanical property without trading off Li-ion conductivity.In this study,focusing on a recently developed cross-linked SPE,i.e.,the one based on poly(vinylene carbonate)-poly(ethylene oxide)cross-linked network(PVCN),we used solid-state nuclear magnetic resonance(NMR)techniques to investigate the fundamental interaction between the chain segments and Li ions,as well as the lithium-ion motion.By utilizing homonuclear/heteronuclear correlation,CP(cross-polarization)kinetics,and spin-lattice relaxation experiments,etc.,we revealed the structural characteristics and their relations to lithium-ion mobilities.It is found that the network formation prevents poly(ethylene oxide)chains from crystallization,which could create sufficient space for segmental tumbling and Li-ion co nductio n.As such,the mechanical property is greatly improved with even higher Li-ion mobilities compared to the poly(vinylene carbonate)or poly(ethylene oxide)based SPE analogues.
基金the Science and Technology Department of Henan Province of China(Grant No.222102240060 and 222300420541)the Education Department of Henan Province of China(Grant No.22B430023)supported by the Program for Innovative Research Team(in Science and Technology)in University of Henan Province(Grant No.23IRTSTHN009)。
文摘Lithium-metal anodes(LMAs)have been recognized as the ultimate anodes for next-generation batteries with high energy density,but stringent assembly-environment conditions derived from the poor moisture stability dramatically hinder the transformation of LMAs from laboratory to industry.Herein,an in situ formed cross-linked polymer layer on LMAs is designed and constructed by a facile thiol-acrylate click chemistry reaction between poly(ethylene glycol)diacrylate(PEGDA)and the crosslinker containing multi thiol groups under UV irradiation.Owing to the hydrophobic nature of the layer,the treated LMAs demonstrate remarkable humid stability for more than 3 h in ambient air(70%relative humidity).The coating humid-resistant protective layer also possesses a dual-functional characterization as solid polymer electrolytes by introducing lithium bis(trifluoromethanesulfonyl)imide in the system in advance.The intimate contact between the polymer layer and LMAs reduces interfacial resistance in the assembled Li/LiFePO_(4)or Li/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)full cell effectively,and endows the cell with an outstanding cycle performance.
基金funding supports from the Natural Science Basis Research Plan in Shaanxi Province of China(2019JLZ-10)the Independent Research Project of National Key Laboratory of Electrical Insulation and Power Equipment(EIPE19111)。
文摘Serving as a promising alternative to liquid electrolyte in the application of portable and wearable devices,gel polymer electrolytes(GPEs)are expected to obtain more preferable properties rather than just be satisfied with the merits of high safety and deformability.Here,an easy-operated method is employed to fabricate cross-linked composite polymer membranes used for GPEs assisted by UV irradiation,in which N-doped carbon quantum dots(N-CQDs)and TiO2are introduced as photocatalysts and additives to improve the performances of GPEs.Specifically,N-CQDs participate as a cross-linker to construct the inner porous structure,and TiO2nanoparticles serve as a stabilizer to improve the electrochemical stability of GPEs under high voltage(3.5 V).The excellent thermal and mechanical stability of the membrane fabricated in this work guarantee the safety of the supercapacitors(SCs).This GPE based SC not only exhibits prominent rate performance(105%capacitance retention at the current density of 40A g^(-1))and cyclic stability(85%at 1 A g^(-1)under 3.5 V after 20,000 cycles),but also displays remarkable energy density(42.88 Wh kg^(-1))with high power density(19.3 k W kg^(-1)).Moreover,the superior rate and cycling performances of the as-prepared GPE based flexible SCs under flat and bending state confirm the feasibility of its application in flexible energy storage devices.
基金supported by R&D Program of Power Batteries with Low Temperature and High Energy,Science and Technology Bureau of Changchun(19SS013)Key Subject Construction of Physical Chemistry of Northeast Normal University+1 种基金the Fundamental Research Funds for the Central Universities(2412020FZ007,2412020FZ008)National Natural Science Foundation of China(22102020)
文摘The self-healing solid polymer electrolytes(SHSPEs)can spontaneously eliminate mechanical damages or micro-cracks generated during the assembly or operation of lithium-ion batteries(LIBs),significantly improving cycling performance and extending service life of LIBs.Here,we report a novel cross-linked network SHSPE(PDDP)containing hydrogen bonds and dynamic disulfide bonds with excellent self-healing properties and nonflammability.The combination of hydrogen bonding between urea groups and the metathesis reaction of dynamic disulfide bonds endows PDDP with rapid self-healing capacity at 28°C without external stimulation.Furthermore,the addition of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMIMTFSI)improves the ionic conductivity(1.13×10^(−4)S cm^(−1)at 28°C)and non-flammability of PDDP.The assembled Li/PDDP/LiFePO_(4)cell exhibits excellent cycling performance with a discharge capacity of 137 mA h g^(−1)after 300 cycles at 0.2 C.More importantly,the self-healed PDDP can recover almost the same ionic conductivity and cycling performance as the original PDDP.
文摘Cross-linking of silyl-modified polymers occurs at the alkoxysilane groups attached to the ends of polymer chains by hydrolysis and polycondensation mechanisms in the presence of moisture. During these reactions, three different physical states can be identified (viscous, skin effect and cross-linked state). Knowledge of the evolution of these states at each reaction time is essential to determine the open time for the adhe-sive industry and is generally obtained by a manual method. Automation of this moni-toring could avoid operator error and could be used for very long cross linking reac-tions or to screen a large number of catalysts. Thus, a contactless micro process tech-nology was developed to correlate these physical states with an optical technology, Raman spectroscopy, by monitoring the decrease in intensity of the Si-OCH<sub>3</sub> groups during chemical reactions. This online characterization method can also be used to compare the efficiencies of several catalysts for the cross-linking of silyl-modified polymers, using a minimum amount of chemical materials.
基金Supported by the National Natural Science Foundation of China (21036009,21176268)the Higher-level Talent Project for Guangdong Provincial Universities+1 种基金the Fundamental Research Funds for the Central UniversitiesGuangdong Province 211 Project
文摘Insoluble β-cyclodextrin polymers were prepared from β-cyclodextrin(β-CD) using epichlorohydrin(EPI) as crosslinking agent under basic conditions.The polymers were characterized by Fourier Transform Infrared(FTIR),Thermogravimetry(TG),X-ray diffraction(XRD) and TG-FTIR.The results demonstrated that the polym-erization between EPI and β-CD indeed occurred,and a number of CD rings were interconnected to form a three-dimensional network.Moreover,different factors influencing the polymerization,e.g.molar ratio of EPI to β-CD,the concentration of NaOH and reaction temperature,have been investigated.The polymer prepared under the optimal conditions(the molar ratio EPI:β-CD of 44,the NaOH concentration 50% in mass,and the temperature at 65 ℃) showed excellent thermal stability and insolubility in organic solvents or strong acid/base.In addition,the β-cyclodextrin polymers also presented high catalytic activity for aqueous oxidation of benzyl alcohol with hy-pochlorite as oxidant.
基金the financial support from the National Natural Science Foundation of China(Nos.21155001 and 21375117)a project funded by the Priority Academic ProgramDevelopment of Jiangsu Higher Education Institutionsthe Foundation of the Excellence Science and Technology Invention Team in Yangzhou University
文摘Ionic liquids functionalized β-cyclodextrin polymer, a mono-6-deoxy-6-(1,2-dimethylimida- zolium)-β-cyclodextrin iodide polymer (ILs-β-CDCP), was synthesized as a solid-phase adsorbent coupled with high-performance liquid chromatography for separating or analyzing magnolol in drug samples. The results showed that magnolol was adsorbed rapidly on ILs-D-CDCP and eluted with methanol. Under the optimum conditions, preconcentration factor of the proposed method was 12. The linear range, limit of detection (LOD), correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.02-8.00 μg/mL, 1.9 ng/mL, 0.9992 and 2.76% (n=3, c=2.00 pg/mL), respectively. The interaction between 1Ls-])-CDCP and magnolol was studied through the inclusion constant, FTIR and TGA analysis. This proposed method has been successfully applied to the determination of magnolol in real samples.
基金supported by National Natural Science Foundation of China(21868002 and 21961160741)the Natural Science Foundation of Guangxi Province(2018GXNSFAA281206,2020GXNSFGA297001,2020GXNSFAA297044)+2 种基金Dean Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2021Z010)Specific research project of Guangxi for research bases and talents(AD18126005)special funding for‘Guangxi Bagui Scholars’,Guangxi scholarship fund for the middle-aged backbone teachers。
文摘Adsorptive recovery of valuable components from industrial wastewater is highly desirable for avoiding resource wastage but remains a challenge.Herein,we develop an efficient continuous adsorption process for recovering aromatic compounds in wastewater from styrene monomer and propylene oxide coproduction(SMPO)plant.Based on our insight into the potential of bio-based porous materials for adsorption application,starch-graft-polystyrene(SPS)and aryl-modifiedβ-cyclodextrin(ACD)were prepared,and novel hypercrosslinked porous polymers combined SPS with ACD(HSPS-ACDs)were synthesized through external crosslinking approach.In a binary-component system,the best-performing one HSPS-ACD(H)with high ACD content and large specific surface area possessed superior capacities for the representative aromatic compounds,acetophenone(AP,2.81 mmol·g^(-1))and 1-phenylethanol(1-PE,1.35 mmol·g^(-1))compared with the previously reported materials.Further,the adsorption properties of aromatic compounds on HSPS-ACD(H)were investigated in batch mode.For practical application,continuous adsorption experiments were conducted in a HSPS-ACD(H)-packed fixed bed,where the target aromatic components in wastewater were effectively retained and further released by elution.Besides showing the reversible adsorption and efficient enrichment effect,the HSPS-ACD(H)-packed fixed bed also maintained great stability in multiple cycles.Moreover,quantum chemical calculations were performed to elucidate the potential mechanism of adsorption of AP and 1-PE onto HSPS-ACD(H).
基金This work was supported by the National Natural Science Foundation of China (No.50573071, No.50533040, No.50703038, No.50773075, and No.50640420265), the National Basic Research Program of China (No.2006cb302900), and the Chinese Academy of Sciences (No.kjcx2.yw.H02).
文摘Three series of amorphous copolymers containing azobenzene groups with various substituents and certain amounts of crosslinkable acrylic groups were prepared. The cross-linked polymer films were obtained by thermal polymerization of the acrylic groups in the copolymers, during which, by controlling the time of cross-linking reaction, the films can be made with different cross-linking degree (from 0 to 32%, which was monitored by FT-IR spectra measurement). Photo-induced alignment process of the films was performed under irradiation with linearly polarized light at 442 nm, and the effect of cross-linking degree on the photo-induced alignment rate was investigated. The dynamics of the photo-induced alignment was analyzed with biexponential curve fitting. The photo-induced alignment rate and the maximum transmittance of the films decreased because of the cross-linking. Furthermore, for the cross-linked samples, it was found that their saturated value of transmittances keep constant after repeated "writing" and "erasing" cycles. The findings reveal that the cross-linking of the film can effectively restrain the phototactic mass transport of azopolymer during irradiation by polarized light. The relationship between the cross-linking degree and the photo-induced alignment behavior of azopolymer is discussed in detail.
基金Imam Abdulrahman Bin Faisal University(IAU),Dammam for providing research facilities.
文摘A new series of polymers comprising four terpolymers was synthesized via Mannich polycondensation of benzene1,4diamine,formaldehyde and piperazine by varying the benzene1,4diamine and piperazine ratio.The new polyamines(labeled Dipip)were characterized using 13C solidstate NMR,FTIR,TGA,DSC,XRD,SEM and EDX.The adsorptive performances of the synthesized polymers for Erichrome Black T(EBT)uptake from aqueous solution were investigated under batch process.Equilibrium,kinetic,and thermodynamic studies were conducted to determine the influence of different operational parameters of the adsorption process.The two most promising polymers among the series show an excellent EBT removal efficiency of~100%and~95%with high adsorption capacities of 775 mgg 1 and 917 mgg 1,respectively at a meager dosage of 5 mg.The sorption of EBT on the polymers was well described by RedlichPeterson&Langmuir model while the kinetic studies indicate that pseudosecond order model was followed.For the thermodynamic studies,the negative AG and positive AH values obtained suggest a spontaneity of the sorption process which was endothermic in nature.The results of reusability test of the resins were promising even at the fourth cycle,showcasing the potentials of the new polymers in dyes contaminated water treatment.
基金Funded by the Natural Science Foundation of China(No.50603032)Education Commission of Chongqing(No.KJ090617)the Science and Technology Plan Project of Jiulongpo District,Chongqing,China(No.2008Q95)
文摘A novel cyclodextrin-containing polymer was prepared by graftingβ-cyclodextrin onto the backbone of poly(D,L-lactic acid)(PLA).First,mono(6-(2-aminoethyl)amino-6-deoxy)-β-cyclodextrin(β-CD-6-en)was prepared by sulfonylation and amination ofβ-cyclodextrin and modified poly(D,L-lactic acid)(MPLA)was prepared by free radical polymerization of maleic anhydride and PLA.Then,grafting ofβ-cyclodextrin derivative to MPLA backbone was carried out by N-acylation reaction of MPLA andβ-CD-6-en in dimethyl formamide.The...
文摘An appropriate amount of toluene 2,4-diisocyanate(TDI) was added into polyether([(CH2CH2O)13 CH2O]n/Li salt electrolyte to form a cross-linked network,with improving the film proces sability and thermal stability.The relation between the structure and ioinc conductive properties of the cross-lined polyether electrolytes was investigated by means of Fourier transform infra-red spectroscopy(FTIR),differential scanning calorimetry(DSC),mechanical property and AC impedance spectroscopy.The electrolytes system is found to have two glass transitions,and it is found that the two Tgs increase with increasing salt concentration.At the some Li salt concentration,the conductivity of cross-liked polyether/LiN(CF3SO2)2 complex system is higher than that of LiClo4,At EO/Li=25:1(mol ratio),the former conductivity changes with temperature,while the later coincids with Arrhenius formula(σ=Ae^-Ea/RT).The cross-linked polyether/LiN(CF3 SO2)2 electrolyte exhibits the maximum σ=10^-4.75S/cm at 30℃.
基金The project is supported by National Natural Science Foundation of China
文摘Different proportions of β-cydodextrin and epichlorohydrin were used to prepare a group of β-cyclodextrin polymers. The relationship between the reaction extent and the molar ratios of reactants was discussed according to the results of ~1H-NMR, ^(13) C-NMR spectra and elemental analysis. Especially, high resolution ~1H-NMR spectra were usd for studying the reaction active sites and the extent of reaction. The solubility of oil soluble drugs in water was largely improved in the presence of water-soluble β-cyclodextrin polymer.
基金financially supported by the National Natural Science Foundation of China(Nos.21574087 and 51973128)Science and Technology Department of Sichuan Province(Nos.2019YJ0128 and 2019YFG0277)supports from the Fundamental Research Funds for the Central Universities。
文摘Lithium-ion batteries(LIBs)benefit from an effective electrolyte system design in both terms of their safety and energy storage capability.Herein,a series of precursor membranes with high porosity were produced using electrospinning technology by mixing PVDF and triblock copolymer(PS-PEO-PS),resulting in a porous structure with good interconnections,which facilitates the absorbency of a large amount of electrolyte and further increases the ionic conductivity of gel polymer electrolytes(GPEs).It has been demonstrated that post-cross-linking of the precursor membranes increa ses the rigidity of the nanofibers,which allows the polymer film to be dimensionally sta ble up to 260℃while maintaining superior electrochemical properties.The obtained cross-linked GPEs(CGPEs)showed high ionic conductivity up to 4.53×10^(-3)S·cm^(-1).With the CGPE-25,the assembled Li/LiFeP04 half cells exhibited good rate capability and maintained a capacity of 99.4%and a coulombic efficiency of99.3%at 0.1 C.These results suggest that the combination of electrospinning technique and post-cross-linking is an effective method to construct polymer electrolytes with high thermal stability and steadily decent electrochemical performance,particularly useful for Lithium-ion battery applications that require high-temperature usage.
基金financially supported by the Guangdong Natural Science Foundation(No.020891)
文摘Cross-linkedβ-cyclodextrin polymer/Fe3O4 composite nanoparticles with core-shell structures were prepared via cross linking reaction on the surface of carboxymethylβ-cyclodextrin(CM-β-CD) modified Fe3O4 nanoparticles inβ-cyclodextrin alkaline solution by using epichlorohydrin as crosslinking agent.The morphology,structure and magnetic properties of the prepared composite nanoparticles were investigated by transmission electron microscopy(TEM),Fourier transform infrared(FTIR) spectrometry,X-ray diffraction(XRD) measurement,thermogravimetric analysis(TGA) and Vibrating sample magnetometry (VSM),respectively.
基金the Chinese National Natural Science Foundation(No.50634020)Scientific and Technological Project of China National Offshore Oil Corporation(No.SC06TJ-PWL-080).
文摘The viscosity property of Cr^3+, Al^3+, and compound ion cross-linked polymer gel solution in the anaerobic and aerobic environment was investigated aiming at meeting the practical demand of the oil field. The viscosity reserving effect after adding the biocide and the gelation in the anaerobic and aerobic environments was also studied in the paper. The results indicate that the viscosity of the cross-linked polymer gel solution caused by the water produced in aerobic environment is higher than that in anaerobic environment, and that the viscosity value of the cross-linked polymer gel solutions after adding biocides has improved to some extent and polymer gel has gelated well in anaerobic environment.
基金supported by the National Natural Science Foundation of China(nos.21975078 and 91833304)the Fundamental Research Funds for the Central Universities,the Introduced Innovative R&D Team of Guangdong Province(no.201101C0105067115)+1 种基金the Natural Science Foundation of Guangdong Province(no.2019B030301003)the 111 Project,and the Thousand Youth Talents Plan.
文摘As two pivotal functional segments,triazine and porphyrin can be coupled to form a highly cross-linked conjugated polymer.Although the obtained conjugated polymers are almost insoluble in most solvents,a small amount of protonic acid can cause the formation of a colloidal solution of polymers.The dissolution process has proved to be a surface charge effect induced by protonation of porphyrin units in the polymer framework.High-quality conjugated polymer films have been prepared on diverse substrates by solution drop-casting and then used for thermoelectric(TE)applications.The films exhibit remarkable TE performance with high Seebeck coefficients(−6650μV K^(−1))and electronic conductivities(0.042 S cm^(−1)),yielding a power factor of 185μW m^(−1) K^(−2),which,collectively,are the highest among all reported n-type organic TE materials.This work may pave the way for the design and development of solution-processed,cross-linked polymer films as promising TE materials.