Recyclable polymers offer a great opportunity to address the environmental issues of plastics.Herein,functionalization of recyclable polymers,poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),were reported via...Recyclable polymers offer a great opportunity to address the environmental issues of plastics.Herein,functionalization of recyclable polymers,poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),were reported via end-group modifications and block/random copolymerizations.Di-n-butylmagnesium was selected to catalyze ring-opening polymerization(ROP)of(R)-M in the presence of a series of functional alcohols as the initiators.Block/random copolymerizations of(R)-M andε-caprolactone(ε-CL),L-lactide(L-LA)and trimethylene carbonate(TMC)were performed to control the onset decomposition temperature(T_(d)),melting temperature(T_(m))and glass transition temperature(T_(g)).These functionalized recyclable polymers would find broad applications as the sustainable plastics.展开更多
Dissolution and homogeneous graft copolymerization of cellulose were performed in an ionic liquid 1-allyl-3-methylimidazolium chloride （AmimCl） with 2-hydroxyethyl methacrylate. The synthesized AmimCl and cellulose ...Dissolution and homogeneous graft copolymerization of cellulose were performed in an ionic liquid 1-allyl-3-methylimidazolium chloride （AmimCl） with 2-hydroxyethyl methacrylate. The synthesized AmimCl and cellulose graft copolymers were characterized by FTIR, ^1 H-NMR and XRD spectroscopy. The results show that AmimCl dissolved cellulose directly by destroying intermolecular and intramolecular hydrogen bonds in cellulose and the crystalline form of cellulose was transformed from cellulose Ⅰ to cellulose Ⅱ after regeneration from AmimCl. The best synthetic condition of the cellulose-graft-P （2-hydroxyethyl methacrylate） was that cellulose 0.5 g, 2-hydroxyethyl methacrylate 3.00 g and initiator ammonium persulfate 0.05 g reacted for 180 min at 60℃; the rate of grafting reached 77.3%.展开更多
The structure of polyolefin has an important influence on its performance and application.Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin.However,research on ...The structure of polyolefin has an important influence on its performance and application.Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin.However,research on the ethylene/1-hexene copolymerization catalyzed by nickel complexes with different steric ligands remains to be refined.Here,three α-dimine nickel catalysts are used to study the ligand effect on catalytic performance in the ethylene/1-hexene copolymerization.Reaction activity,molecular weight,phase-transition temperature and branching density of the resultant copolymer are measured to evaluate the catalytic performance.The results indicate that the steric ligands could exert great effect on the copolymerization.As for the chemical valence of Ni species,detailed EPR demonstrate that the presence of excess xo-catalyst can reduce Ni(Ⅱ)to the lower valence and affect the catalytic performance.展开更多
In this paper, various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) were eopolymerized b...In this paper, various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) were eopolymerized by radiation technique at low temperature (-78℃) and several kinds of copolymer carriers were obtained. Yeast cells were immobilized through adhesion and multiplication of yeast cells themselves on these carriers. The etharol productivity of immobilized yeast cells with these carriers was related to the monomer composition and water content of copolymer carriers and the optimum monomer composition was 20%:10% in poly (HEA-M23G). In this case, the ethanol productivity of immobilized yeast cells was 26 mg /( ml·h), which was 4 times as high as that of free cells. In this study, the effect of adding of crosslinking reagent (4G) in copolymer on activity of yeast cells immobilized with the carriers were also studied. It was found that the effect of adding crosslinking reagent (4G) in lower monomer composition of poly(HEA-M23G) on the ethanol productivity of immobilized cells was better than that in higher one in this work.展开更多
Two allyldimethylalkyl quaternary ammonium salt(AQAS)monomers,N,N-dimethylallylphenylpropylammonium bromide(AQAS1)and N,N-dimethylallylnonylammonium bromide(AQAS2),were synthesized and used to prepare modified polyacr...Two allyldimethylalkyl quaternary ammonium salt(AQAS)monomers,N,N-dimethylallylphenylpropylammonium bromide(AQAS1)and N,N-dimethylallylnonylammonium bromide(AQAS2),were synthesized and used to prepare modified polyacrylamide materials.Two new drag reducers were synthesized from acrylamide(AM),sodium acrylate(Na AA)and a cationic modified monomer(AQAS1 or AQAS2)via aqueous solution polymerization,and the copolymers were named P(AM/Na AA/AQAS1)and P(AM/Na AA/AQAS2),respectively.The structures of the drag reduction agents were confirmed by IR and1H NMR spectroscopies.The molecular weight(Mw)of P(AM/Na AA/AQAS1)was 1.79×10^(6)g/mol.When the copolymer concentration was 1000 mg/L and the flow rate was 45 L/min,in fresh water the highest drag reduction rate was 75.8%,in 10,000 mg/L Na Cl solution the drag reduction rate decreased to 72.9%.The molecular weight of P(AM/Na AA/AQAS2)was 3.17×10^(6)g/mol.When the copolymer concentration was500 mg/L and the flow rate was 45 L/min,the drag reduction rate reached 75.2%,and in 10,000 mg/L Na Cl solution the drag reduction rate was 73.3%,decreased by approximately 1.9%.The drag reduction rate for partially hydrolyzed polyacrylamide(HPAM)was also investigated,and the results showed that the drag reduction rates for 500 and 1000 mg/L HPAM solutions were merely 43.2%and 49.0%in brine,respectively.Compared with HPAM,both of the above copolymers presented better drag reduction capacities.展开更多
Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not bee...Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not been very effective in high-temperature drilling operations. Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials, which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization. This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions. A novel thermoresponsive Janus nanosilica(TRJS) exhibiting zwitterionic character was synthesized, characterized,and assessed as shale stabilizer for WBDFs at high temperatures. Compared to pristine nanosilica(Si NP)and symmetrical thermo-responsive nanosilica(TRS), TRJS exhibited anti-polyelectrolyte behaviour, in which electrolyte ions screened the electrostatic attraction between the charged particles, potentially stabilizing nanomaterial in hostile shaly environments(i.e., up to saturated brine or API brine). Macroscopically, TRJS exhibited higher chemical inhibition than Si NP and TRS in brine, prompting a better capability to control pressure penetration. TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding, and the interactions became substantial in brine, according to the results of electrophoretic mobility, surface wettability, and X-ray diffraction. Thus, contributing to the firm trapping of TRJS into the nanopore structure of the shale, triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere. The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190℃, implying that TRJS could find potential use as a shale stabilizer in WBDFs in hostile environments.展开更多
Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility wit...Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility with electrodes.Herein,a novel all-solid polymer electrolyte(PPLCE)was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol)dimethacrylate(PEGDMA)acts as a structural frame,combined with poly(ethylene glycol)diglycidyl ether short chain interspersed serving as mobile ion transport entities.The preparaed PPLCEs exhibit excellent mechanical property and out-standing electrochemical performances,which is attributed to their unique three-dimensional cocontinuous structure,characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase,resulting in a distinctive nanostructure with short-range order and long-range disorder.Remarkably,the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs,which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid electrolyte.When used in a lithiumion symmetrical battery configuration,the 6 wt%-PPLCE exhibites super stability,sustaining operation for over 2000 h at 30 C,with minimal and consistent overpotential of 50 mV.The resulting Li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 120.1 mA h g^(-1)at current densities of 0.2 and 1 C,respectively.Even after more than 300 cycles at a current density of 0.2 C,it retaines an impressive 73.5%capacity.Moreover,it displayes stable cycling for over 180 cycles at a high current density of 0.5C.The super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries.展开更多
The following copolymers based on aliphatic sebacic acid were synthesized through a vacuum-melt polycondensation process:poly(sebacic acid)-b-poly(isophthalic acid)(PSA-PIPH).poly (sebacic acid) -b- (tartaric acid) (P...The following copolymers based on aliphatic sebacic acid were synthesized through a vacuum-melt polycondensation process:poly(sebacic acid)-b-poly(isophthalic acid)(PSA-PIPH).poly (sebacic acid) -b- (tartaric acid) (PSA-PTTA). poly (sebacic acid) -b-poly (ethylene glycol)(PSA-PEG). copolymers of PSA and copolyether (M1= 1500) of epoxy ethane and (tetrahydrofuran)(PSA-PEG/THF). All these copolymers were characterized by means of 1H or 13C NMR. IR spectrometry. differential scanning calorimetry (DSC). Intrinsic viscosity and melting points were measured to estimate the molecular weights of polymers. DSC measurements indicated that PSA-PEG. PSA-PEG/THF have much lower crystallinity. On the other hand,PSA-PIPH and PSA-PTTA exhibit better film or fibre-forming properties than PSA.展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by graf...An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications展开更多
The acidic effect in grafting of acrylonitrile onto wool fibre under mutual irradiation has been studied. The reactivity of various acids towards graft copolymerization was found as the order: H<sub>2</sub>...The acidic effect in grafting of acrylonitrile onto wool fibre under mutual irradiation has been studied. The reactivity of various acids towards graft copolymerization was found as the order: H<sub>2</sub>SO<sub>4</sub>】HNO<sub>3</sub>】HCl】HClO<sub>4</sub>】HOAC.展开更多
Poly(aspartic acid-itaconic acid) copolymer was synthesized from aspartic acid(Asp) and itaconic acid(Ita) under microwave irradiation. The effects of microwave power, microwave irradiation time, molar ratio of itacon...Poly(aspartic acid-itaconic acid) copolymer was synthesized from aspartic acid(Asp) and itaconic acid(Ita) under microwave irradiation. The effects of microwave power, microwave irradiation time, molar ratio of itaconic acid and aspartic acid, catalyst type, catalyst and organic solvent content on copolymer yield, and the performance for inhibition of CaCO_3 fouling were investigated. It was found that the product yield achieved a highest record of 95% when the amount of catalyst Na H_2PO_4 was 0.012 mol, the amount of organic solvent propylene carbonate was 16 m L, the molar ratio of Asp/Ita was 3:1, the microwave output power was 1200 W and the irradiation time was 5.5 min. And the product performance for inhibition of calcium carbonate also reached a highest value of 94.38%. Structural characterization of the product showed that the product was the aspartic acid-itaconic acid copolymer.展开更多
The special gas wettability phenomenon of reservoir rocks has been recognized by more and more researchers.It has a significant effect on efficient development of unconventional reservoirs.First,based on the preferent...The special gas wettability phenomenon of reservoir rocks has been recognized by more and more researchers.It has a significant effect on efficient development of unconventional reservoirs.First,based on the preferentially gas-covered ability and surface free energy changes,definition and evaluation methods have been established.Second,a method for altering rock wettability and its mechanisms have been studied,surface oriented phenomena of functional groups with low surface energy are the fundamental reason for gas wettability alteration of rock.Third,the effect of gas wettability on the surface energy,electrical properties and dilatability are investigated.Last,the effects of gas wettability on capillary pressure,oil/gas/water distribution and flow are investigated with capillary tubes and etchedglass network models.The gas wettability theory of reservoir rocks has been initially established,which provides theoretical support for the efficient production of unconventional reservoirs and has great significance.展开更多
Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactiv...Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactive lithium metal result in the severe safety risks and the short lifespan for highenergy-density rechargeable batteries.Here,we demonstrate a hydrophobic and ionically conductive ethylene-vinyl acetate(EVA)copolymer layer can not only endow lithium metal anodes with an air-stable and anti-water surface,but also efficiently suppress the lithium-dendrites growth during the electrochemical cycling process.Therefore,the introduction of the EVA copolymer as a bifunctional protection layer simultaneously improves the anti-water/air performance and electrochemical cycling stability of lithium metal anode.展开更多
Nitrogen-doped carbon materials encapsulating 3 d transition metals are promising alternatives to replace noble metal Pt catalysts for efficiently catalyzing the oxygen reduction reaction(ORR). Herein, we use cobalt s...Nitrogen-doped carbon materials encapsulating 3 d transition metals are promising alternatives to replace noble metal Pt catalysts for efficiently catalyzing the oxygen reduction reaction(ORR). Herein, we use cobalt substituted perfluorosulfonic acid/polytetrafluoroethylene copolymer and dicyandiamide as the pyrolysis precursor to synthesize nitrogen-doped carbon nanotube(N–CNT) encapsulating cobalt nanoparticles hybrid material. The carbon layers and specific surface area of N–CNT have a critical role to the ORR performance due to the exposed active sites, determined by the mass ratio of the two precursors. The optimum hybrid material exhibits high ORR activity and stability, as well as excellent performance and durability in zinc–air battery.展开更多
Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by...Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by using maleic anhydride （MA） and vinyl acetate （VA） as raw materials, toluene as solvent, dibenzoyl peroxide （BPO） as initiator, through alternating polymerization under nitrogen to obtain a binary-polymer and then through aminolysis by using a higher carbon amine as aminating agent at a temperature of 80 ℃. A cold flow improver was designed and prepared for No. 0 diesel fuel from Zhang Jia-Gang Petrochemical Company according to the contents of n-paraffin and its carbon number distribution in the No. 0 diesel fuel. It was also used together with two kinds of ethene-vinyl acetate copolymer improvers （EVA） separately. The test result showed that the CFPP of the No. 0 diesel fuel could be lowered by 3-5 ℃ when the improver MAVA-a was used. The CFPP was lowered by 8℃ when the improver MAVA-a was used together with EVA-2.展开更多
Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes a...Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes are still limited by the low ionic conductivity,poor interfacial contact with electrodes,narrow electrochemical window and weak mechanical strength.Here,a series of novel block copolymer electrolytes with three-dimensional networks are designed by cross-linked copolymerization of the polyethylene glycol soft segments and hexamethylene diisocyanate trimer hard segments.Their ionic migration performances and interface compatibilities with Li metal anode have been optimized delicately by tailoring the ratio of these functional units.The optimized block copolymer electrolyte has shown an amorphous crystalline structure,a high ionic conductivity of ~5.7×10^(-4)S cm^(-1),high lithium ion transference number(~0.49),wide electrochemical window up to ~4.65 V(vs.Li+/Li) and favorable mechanical strength at 55℃.Furthermore,the enhanced interface compatibility can well support the normal operations of lithium metal batteries using both LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes.This study not only paves a new way to develop solid polymer electrolyte with optimizing functional units,but also provides a polymer electrolyte design strategy for the application demand of lithium metal battery.展开更多
Ordered porous cabon with a 2-D hexagonal structure,high specific surface area and large pore volume was synthesized through a twostep heating method using tri-block copolymer as template and phenolic resin as carbon ...Ordered porous cabon with a 2-D hexagonal structure,high specific surface area and large pore volume was synthesized through a twostep heating method using tri-block copolymer as template and phenolic resin as carbon precursor.The results indicated the electrochemical performance of the sulfur/carbon composites prepared with the ordered porous carbon was significantly affected by the pore structure of the carbon.Both the specific capacity and cycling stability of the sulfur/carbon composites were improved using the bimodal micro/meso-porous carbon frameworks with high surface area.Its initial discharge capacity can be as high as 1200 mAh·g-1 at a current density of 167.5 mA·g-1The improved capacity retention was obtained during the cell cycling as well.展开更多
Solid-state lithium(Li) metal batteries overwhelm the lithium-ion batteries by harvesting high energy from Li metal anode with ultrahigh capacities and gaining excellent safety from solid electrolytes.However,the unco...Solid-state lithium(Li) metal batteries overwhelm the lithium-ion batteries by harvesting high energy from Li metal anode with ultrahigh capacities and gaining excellent safety from solid electrolytes.However,the uncontrollable solvents in solid electrolytes usually aggravate poor interfacial contact with lithium metal anode and deteriorate Li^(+) pathways.Here a copolymeric network-structured ion conductor by rationally integrating cellulose nanofibril as a two-in-one functional material is employed to anchor the solvent.Taking advantages of tightly anchoring of cellulose nanofibril to solvent,the asconstructed quasi-solid polymer-based electrolyte offers rapid Li^(+) transport channels and realizes effective Li-dendrite suppression,which enables high ionic conductivity of 1.93 × 10^(-3)S cm^(-1) at room temperature,long-term Li plating/stripping over 1900 h,and high capacity retention of 99%.This work provides a fresh strategy for creating solid electrolytes that meet both high ionic conductivity and interfacial stability requirements for practical solid-state lithium metal battery.展开更多
基金supported by The National Natural Science Foundation of China(21504039)。
文摘Recyclable polymers offer a great opportunity to address the environmental issues of plastics.Herein,functionalization of recyclable polymers,poly((R)-3,4-trans six-membered ring-fused GBL)(P((R)-M)),were reported via end-group modifications and block/random copolymerizations.Di-n-butylmagnesium was selected to catalyze ring-opening polymerization(ROP)of(R)-M in the presence of a series of functional alcohols as the initiators.Block/random copolymerizations of(R)-M andε-caprolactone(ε-CL),L-lactide(L-LA)and trimethylene carbonate(TMC)were performed to control the onset decomposition temperature(T_(d)),melting temperature(T_(m))and glass transition temperature(T_(g)).These functionalized recyclable polymers would find broad applications as the sustainable plastics.
基金supported by the 11th Five-Year Plan of the National Scientific and Technological Support Projects of China (Grant No. 2006BAD18B10)the Major Project of Chinese National Programs for Fundamental Research and Development (973 Program) (Grant No. 2010CB732204)
文摘Dissolution and homogeneous graft copolymerization of cellulose were performed in an ionic liquid 1-allyl-3-methylimidazolium chloride （AmimCl） with 2-hydroxyethyl methacrylate. The synthesized AmimCl and cellulose graft copolymers were characterized by FTIR, ^1 H-NMR and XRD spectroscopy. The results show that AmimCl dissolved cellulose directly by destroying intermolecular and intramolecular hydrogen bonds in cellulose and the crystalline form of cellulose was transformed from cellulose Ⅰ to cellulose Ⅱ after regeneration from AmimCl. The best synthetic condition of the cellulose-graft-P （2-hydroxyethyl methacrylate） was that cellulose 0.5 g, 2-hydroxyethyl methacrylate 3.00 g and initiator ammonium persulfate 0.05 g reacted for 180 min at 60℃; the rate of grafting reached 77.3%.
基金Financial support from the National Key Research and Development Program(2016YFB0302403)is gratefully acknowledged.
文摘The structure of polyolefin has an important influence on its performance and application.Ethylene/1-hexene copolymerization is one of the important ways to control the structure of the polyolefin.However,research on the ethylene/1-hexene copolymerization catalyzed by nickel complexes with different steric ligands remains to be refined.Here,three α-dimine nickel catalysts are used to study the ligand effect on catalytic performance in the ethylene/1-hexene copolymerization.Reaction activity,molecular weight,phase-transition temperature and branching density of the resultant copolymer are measured to evaluate the catalytic performance.The results indicate that the steric ligands could exert great effect on the copolymerization.As for the chemical valence of Ni species,detailed EPR demonstrate that the presence of excess xo-catalyst can reduce Ni(Ⅱ)to the lower valence and affect the catalytic performance.
基金This research projcct was financed by applied base research fund of jiangsu provicial Scicntific and Tcchniquuc Committee from 1989-1991
文摘In this paper, various kinds of monomers 2-hydroxyethyl methacrylate (HEMA), 2-hydroxyethyl acrylate (HEA), hydroxypropyl methacrylate (HPMA) and methoxy polyethylene glycol methylacrylate (M-23G) were eopolymerized by radiation technique at low temperature (-78℃) and several kinds of copolymer carriers were obtained. Yeast cells were immobilized through adhesion and multiplication of yeast cells themselves on these carriers. The etharol productivity of immobilized yeast cells with these carriers was related to the monomer composition and water content of copolymer carriers and the optimum monomer composition was 20%:10% in poly (HEA-M23G). In this case, the ethanol productivity of immobilized yeast cells was 26 mg /( ml·h), which was 4 times as high as that of free cells. In this study, the effect of adding of crosslinking reagent (4G) in copolymer on activity of yeast cells immobilized with the carriers were also studied. It was found that the effect of adding crosslinking reagent (4G) in lower monomer composition of poly(HEA-M23G) on the ethanol productivity of immobilized cells was better than that in higher one in this work.
基金supported by the National Natural Science Foundation of China(Project Nos.51774062 and 52274032)Scientific and Technological Key Research Program of Chongqing Municipal Education Commission(KJZD-K201901502)+1 种基金General Project of Chongqing Natural Science Foundation(CSTB2022NSCQMSX0349)Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202313101)。
文摘Two allyldimethylalkyl quaternary ammonium salt(AQAS)monomers,N,N-dimethylallylphenylpropylammonium bromide(AQAS1)and N,N-dimethylallylnonylammonium bromide(AQAS2),were synthesized and used to prepare modified polyacrylamide materials.Two new drag reducers were synthesized from acrylamide(AM),sodium acrylate(Na AA)and a cationic modified monomer(AQAS1 or AQAS2)via aqueous solution polymerization,and the copolymers were named P(AM/Na AA/AQAS1)and P(AM/Na AA/AQAS2),respectively.The structures of the drag reduction agents were confirmed by IR and1H NMR spectroscopies.The molecular weight(Mw)of P(AM/Na AA/AQAS1)was 1.79×10^(6)g/mol.When the copolymer concentration was 1000 mg/L and the flow rate was 45 L/min,in fresh water the highest drag reduction rate was 75.8%,in 10,000 mg/L Na Cl solution the drag reduction rate decreased to 72.9%.The molecular weight of P(AM/Na AA/AQAS2)was 3.17×10^(6)g/mol.When the copolymer concentration was500 mg/L and the flow rate was 45 L/min,the drag reduction rate reached 75.2%,and in 10,000 mg/L Na Cl solution the drag reduction rate was 73.3%,decreased by approximately 1.9%.The drag reduction rate for partially hydrolyzed polyacrylamide(HPAM)was also investigated,and the results showed that the drag reduction rates for 500 and 1000 mg/L HPAM solutions were merely 43.2%and 49.0%in brine,respectively.Compared with HPAM,both of the above copolymers presented better drag reduction capacities.
基金financially supported by the National Natural Science Foundation of China(Grant No.52150410427)the Key Support Program for Foreign Experts of the Ministry of Science and Technology of the People's Republic of China(No.wgxz2022057)funding for post-doctoral work by the Department of Human Resources and Social Security of Hubei Province。
文摘Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not been very effective in high-temperature drilling operations. Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials, which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization. This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions. A novel thermoresponsive Janus nanosilica(TRJS) exhibiting zwitterionic character was synthesized, characterized,and assessed as shale stabilizer for WBDFs at high temperatures. Compared to pristine nanosilica(Si NP)and symmetrical thermo-responsive nanosilica(TRS), TRJS exhibited anti-polyelectrolyte behaviour, in which electrolyte ions screened the electrostatic attraction between the charged particles, potentially stabilizing nanomaterial in hostile shaly environments(i.e., up to saturated brine or API brine). Macroscopically, TRJS exhibited higher chemical inhibition than Si NP and TRS in brine, prompting a better capability to control pressure penetration. TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding, and the interactions became substantial in brine, according to the results of electrophoretic mobility, surface wettability, and X-ray diffraction. Thus, contributing to the firm trapping of TRJS into the nanopore structure of the shale, triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere. The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190℃, implying that TRJS could find potential use as a shale stabilizer in WBDFs in hostile environments.
基金supported by the National Natural Science Foundation of China(52003293,51927806,52272258)the Fundamental Research Funds for the Central Universities(2023ZKPYJD07)the Beijing Nova Program(20220484214).
文摘Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility with electrodes.Herein,a novel all-solid polymer electrolyte(PPLCE)was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol)dimethacrylate(PEGDMA)acts as a structural frame,combined with poly(ethylene glycol)diglycidyl ether short chain interspersed serving as mobile ion transport entities.The preparaed PPLCEs exhibit excellent mechanical property and out-standing electrochemical performances,which is attributed to their unique three-dimensional cocontinuous structure,characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase,resulting in a distinctive nanostructure with short-range order and long-range disorder.Remarkably,the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs,which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid electrolyte.When used in a lithiumion symmetrical battery configuration,the 6 wt%-PPLCE exhibites super stability,sustaining operation for over 2000 h at 30 C,with minimal and consistent overpotential of 50 mV.The resulting Li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 120.1 mA h g^(-1)at current densities of 0.2 and 1 C,respectively.Even after more than 300 cycles at a current density of 0.2 C,it retaines an impressive 73.5%capacity.Moreover,it displayes stable cycling for over 180 cycles at a high current density of 0.5C.The super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries.
文摘The following copolymers based on aliphatic sebacic acid were synthesized through a vacuum-melt polycondensation process:poly(sebacic acid)-b-poly(isophthalic acid)(PSA-PIPH).poly (sebacic acid) -b- (tartaric acid) (PSA-PTTA). poly (sebacic acid) -b-poly (ethylene glycol)(PSA-PEG). copolymers of PSA and copolyether (M1= 1500) of epoxy ethane and (tetrahydrofuran)(PSA-PEG/THF). All these copolymers were characterized by means of 1H or 13C NMR. IR spectrometry. differential scanning calorimetry (DSC). Intrinsic viscosity and melting points were measured to estimate the molecular weights of polymers. DSC measurements indicated that PSA-PEG. PSA-PEG/THF have much lower crystallinity. On the other hand,PSA-PIPH and PSA-PTTA exhibit better film or fibre-forming properties than PSA.
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
文摘An attempt was made in the paper aiming at imparting flame retardancy to polymers by plasma grafting technique Based on EVA copolymers with different VA contents the author tried to use the Ar plasma followed by grafting with/without subsequent saponification and metal ion exchange expediting the charring of polymers upon heationg Characterization of the flammability of the plasma treated EVA copolymers grafted with acrylic monomers(MAA,AA and AAm)indicates that this approach turns out to be a promising way and worthy doing whatever in research and/or applications
基金The Project Supported by National Natural Science Foundation of China
文摘The acidic effect in grafting of acrylonitrile onto wool fibre under mutual irradiation has been studied. The reactivity of various acids towards graft copolymerization was found as the order: H<sub>2</sub>SO<sub>4</sub>】HNO<sub>3</sub>】HCl】HClO<sub>4</sub>】HOAC.
基金supported financially from the National Natural Science Foundation of China (Grant No. 51308211)the State Key Laboratory of Urban Water Resource and Environment (HIT) (Grant No. ES200903)the Fundamental Research Funds for the Central Universities (Grant No. 2015MS63)
文摘Poly(aspartic acid-itaconic acid) copolymer was synthesized from aspartic acid(Asp) and itaconic acid(Ita) under microwave irradiation. The effects of microwave power, microwave irradiation time, molar ratio of itaconic acid and aspartic acid, catalyst type, catalyst and organic solvent content on copolymer yield, and the performance for inhibition of CaCO_3 fouling were investigated. It was found that the product yield achieved a highest record of 95% when the amount of catalyst Na H_2PO_4 was 0.012 mol, the amount of organic solvent propylene carbonate was 16 m L, the molar ratio of Asp/Ita was 3:1, the microwave output power was 1200 W and the irradiation time was 5.5 min. And the product performance for inhibition of calcium carbonate also reached a highest value of 94.38%. Structural characterization of the product showed that the product was the aspartic acid-itaconic acid copolymer.
基金supported by the Basic Research on Drilling & Completion of Critical Wells for Oil & Gas (Grant No. 51221003)National Science Fund for Petrochemical Industry (Project No. U1262201)+2 种基金"863" National Project (Project No. 2013AA064803)National Science Fund for Distinguished Young Scholars (Project No. 50925414)National Natural Science Foundation (Project No. 51074173)
文摘The special gas wettability phenomenon of reservoir rocks has been recognized by more and more researchers.It has a significant effect on efficient development of unconventional reservoirs.First,based on the preferentially gas-covered ability and surface free energy changes,definition and evaluation methods have been established.Second,a method for altering rock wettability and its mechanisms have been studied,surface oriented phenomena of functional groups with low surface energy are the fundamental reason for gas wettability alteration of rock.Third,the effect of gas wettability on the surface energy,electrical properties and dilatability are investigated.Last,the effects of gas wettability on capillary pressure,oil/gas/water distribution and flow are investigated with capillary tubes and etchedglass network models.The gas wettability theory of reservoir rocks has been initially established,which provides theoretical support for the efficient production of unconventional reservoirs and has great significance.
基金supported by the National Key Research and Development Program(2016YFA0202500)National Natural Science Foundation of China(21776019,21808124,51972121)+1 种基金Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2017TQ04C419)Beijing Natural Science Foundation(L182021)。
文摘Lithium metal batteries are strongly considered as one of the most promising candidates for nextgeneration high-performance battery systems.However,the uncontrollable growth of lithium dendrites and the highly reactive lithium metal result in the severe safety risks and the short lifespan for highenergy-density rechargeable batteries.Here,we demonstrate a hydrophobic and ionically conductive ethylene-vinyl acetate(EVA)copolymer layer can not only endow lithium metal anodes with an air-stable and anti-water surface,but also efficiently suppress the lithium-dendrites growth during the electrochemical cycling process.Therefore,the introduction of the EVA copolymer as a bifunctional protection layer simultaneously improves the anti-water/air performance and electrochemical cycling stability of lithium metal anode.
基金financial support from the Ministry of Science and Technology of China(Grants 2016YFB0600901 and 2013CB933100)the National Natural Science Foundation of China(Grants 21573222 and 91545202)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB17020200)financial support from CAS Youth Innovation Promotion(Grant No.2015145)
文摘Nitrogen-doped carbon materials encapsulating 3 d transition metals are promising alternatives to replace noble metal Pt catalysts for efficiently catalyzing the oxygen reduction reaction(ORR). Herein, we use cobalt substituted perfluorosulfonic acid/polytetrafluoroethylene copolymer and dicyandiamide as the pyrolysis precursor to synthesize nitrogen-doped carbon nanotube(N–CNT) encapsulating cobalt nanoparticles hybrid material. The carbon layers and specific surface area of N–CNT have a critical role to the ORR performance due to the exposed active sites, determined by the mass ratio of the two precursors. The optimum hybrid material exhibits high ORR activity and stability, as well as excellent performance and durability in zinc–air battery.
基金Supported by the Basic Research Program of the State Key Laboratory of Heavy Oil Processing (200310) China University of Petroleum,Beijing,China
文摘Synthesis of a cold flow improver （MAVA-a） for diesel fuel and its effect on solidifying point （SP） and cold filter plugging point （CFPP） of diesel fuels were investigated, The cold flow improver was prepared by using maleic anhydride （MA） and vinyl acetate （VA） as raw materials, toluene as solvent, dibenzoyl peroxide （BPO） as initiator, through alternating polymerization under nitrogen to obtain a binary-polymer and then through aminolysis by using a higher carbon amine as aminating agent at a temperature of 80 ℃. A cold flow improver was designed and prepared for No. 0 diesel fuel from Zhang Jia-Gang Petrochemical Company according to the contents of n-paraffin and its carbon number distribution in the No. 0 diesel fuel. It was also used together with two kinds of ethene-vinyl acetate copolymer improvers （EVA） separately. The test result showed that the CFPP of the No. 0 diesel fuel could be lowered by 3-5 ℃ when the improver MAVA-a was used. The CFPP was lowered by 8℃ when the improver MAVA-a was used together with EVA-2.
基金supported financially by the National Key R&D Program of China (Grant No. 2018YFB0104300)Beijing Natural Science Foundation (JQ19003, KZ201910005002 and L182009)+1 种基金National Natural Science Foundation of China (Grants 21875007, 51622202, and 21974007)the Project of Youth Talent Plan of Beijing Municipal Education Commission (CIT&TCD201804013)。
文摘Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes are still limited by the low ionic conductivity,poor interfacial contact with electrodes,narrow electrochemical window and weak mechanical strength.Here,a series of novel block copolymer electrolytes with three-dimensional networks are designed by cross-linked copolymerization of the polyethylene glycol soft segments and hexamethylene diisocyanate trimer hard segments.Their ionic migration performances and interface compatibilities with Li metal anode have been optimized delicately by tailoring the ratio of these functional units.The optimized block copolymer electrolyte has shown an amorphous crystalline structure,a high ionic conductivity of ~5.7×10^(-4)S cm^(-1),high lithium ion transference number(~0.49),wide electrochemical window up to ~4.65 V(vs.Li+/Li) and favorable mechanical strength at 55℃.Furthermore,the enhanced interface compatibility can well support the normal operations of lithium metal batteries using both LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes.This study not only paves a new way to develop solid polymer electrolyte with optimizing functional units,but also provides a polymer electrolyte design strategy for the application demand of lithium metal battery.
基金supported by the National High Technology Research and Development Program of China(863 Program)the Strategic Priority Research Program of the Chinese Academy of Sciences
文摘Ordered porous cabon with a 2-D hexagonal structure,high specific surface area and large pore volume was synthesized through a twostep heating method using tri-block copolymer as template and phenolic resin as carbon precursor.The results indicated the electrochemical performance of the sulfur/carbon composites prepared with the ordered porous carbon was significantly affected by the pore structure of the carbon.Both the specific capacity and cycling stability of the sulfur/carbon composites were improved using the bimodal micro/meso-porous carbon frameworks with high surface area.Its initial discharge capacity can be as high as 1200 mAh·g-1 at a current density of 167.5 mA·g-1The improved capacity retention was obtained during the cell cycling as well.
基金financial support from the projects of the National Natural Science Foundation of China (52373074 and 51972121)the Independent Research Project of Maoming Laboratory (2022ZD002)。
文摘Solid-state lithium(Li) metal batteries overwhelm the lithium-ion batteries by harvesting high energy from Li metal anode with ultrahigh capacities and gaining excellent safety from solid electrolytes.However,the uncontrollable solvents in solid electrolytes usually aggravate poor interfacial contact with lithium metal anode and deteriorate Li^(+) pathways.Here a copolymeric network-structured ion conductor by rationally integrating cellulose nanofibril as a two-in-one functional material is employed to anchor the solvent.Taking advantages of tightly anchoring of cellulose nanofibril to solvent,the asconstructed quasi-solid polymer-based electrolyte offers rapid Li^(+) transport channels and realizes effective Li-dendrite suppression,which enables high ionic conductivity of 1.93 × 10^(-3)S cm^(-1) at room temperature,long-term Li plating/stripping over 1900 h,and high capacity retention of 99%.This work provides a fresh strategy for creating solid electrolytes that meet both high ionic conductivity and interfacial stability requirements for practical solid-state lithium metal battery.
