Polyacrylic acid(PAA)-based binders have been demonstrated to significantly enhance the cycling stability of pure silicon(Si)anodes compared to other binder types.However,there is a notable lack of systematic and in-d...Polyacrylic acid(PAA)-based binders have been demonstrated to significantly enhance the cycling stability of pure silicon(Si)anodes compared to other binder types.However,there is a notable lack of systematic and in-depth investigation into the relationship between the molecular weight(MW)of PAA and its performance in pure Si anodes,leading to an absence of reliable theoretical guidance for designing and optimizing of PAA-based binders for these anodes.Herein,we select a series of PAA with varying MWs as binders for Si nanoparticle(SiNP)anodes to systematically identify the optimal MW of PAA for enhancing the electrochemical performance of SiNP anodes.The actual MWs of the various PAA were confirmed by gel permeation chromatography to accurately establish the relationship between MW and binder performance.Within an ultrawide weight average molecular weight(M_(w))range of 35.9-4850 kDa,we identify that the PAA binder with a M_(w)of 1250 kDa(PAA125)exhibits the strongest mechanical strength and the highest adhesion strength,attributed to its favorable molecular chain orientation and robust interchain interactions.These characteristics enable the SiNP anodes utilizing PAA125 to maintain the best interfacial chemistry and bulk mechanical structure stability,leading to optimal electrochemical performance.Notably,the enhancement in cycling stability of SiNP anode by PAA125 under practical application conditions is further validated by the 1.1 Ah LLNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/SiNP@PAA125 pouch cell.展开更多
The effect of polyacrylic acid(PAA)on the corrosion behavior of Alloy 690 in simulated pressurized water reactor secondary water was investigated.The duplex oxide film structure,consisting of a Ni-rich outer layer and...The effect of polyacrylic acid(PAA)on the corrosion behavior of Alloy 690 in simulated pressurized water reactor secondary water was investigated.The duplex oxide film structure,consisting of a Ni-rich outer layer and a Cr-rich inner layer,was maintained regardless of PAA presence.PAA inhibited the growth of outer Ni-rich particles while promoting Cr enrichment in the inner layer and inducing its amorphization,both enhancing oxidation resistance.However,excess PAA(≥500 ppb)suppressed protective oxide formation during initial oxidation,leading to oxygen penetration into the matrix.A PAA concentration of around 250 ppb is considered optimal for steam generators,as it provides the benefits of PAA without adverse effects on the alloy.展开更多
A self-made AMPS-modified polyacrylic acid superplasticizer and two others of the same type but with different molecular structures, which are commercially available, are used in this study to investigate the effect o...A self-made AMPS-modified polyacrylic acid superplasticizer and two others of the same type but with different molecular structures, which are commercially available, are used in this study to investigate the effect of a 2-acrylamide-2-methyl propylene sulfonic （AMPS）-modified polyacrylic acid superplasticizer on the properties of cement-based materials. In the experiments, initial fluidity, 1 and 2 h fluidity over time after admixtion, bleeding rate of the net cement mortar, and adsorption capacity and rate of cement particles are determined by adding different dosages of the three superplasticizers into the cement paste to characterize the dispersivity and the dispersion retention capability of each superplasticizer. Water-reducing rates of three kinds of mortars are simultaneously determined to characterize the water-reducing capacity of each superplasticizer, as well as the 3 and 28 d compressive strengths to characterize the compression resistance. Results show that water-reducing effect and fluidity better maintain the capability of the AMPS-modified polyacrylic acid superplasticizer than the two commercially available polyacrylic acid superplasticizers, and the compressive strengths after 3 and 28 d show significant growth. In conclusion, the effects of water reduction and strengthening of the AMPS-modified polyacrylic acid superplasticizer are evidently better than those of the two commercially available polyacrylic acid superplasticizers.展开更多
A macromer, methoxypolyethylene glycol acrylate （MPEGAA）, was synthesized by direct esterification using methoxypolyethylene glycol （MPEG-1200） and acrylic acid （AA） as the main materials. MPEGAA was then used t...A macromer, methoxypolyethylene glycol acrylate （MPEGAA）, was synthesized by direct esterification using methoxypolyethylene glycol （MPEG-1200） and acrylic acid （AA） as the main materials. MPEGAA was then used to prepare a polyacrylic acid superplasticizer modified with 2-acrylamido-2- methylpropane sulfonic acid （AMPS）. A single-factor test was performed to investigate the effects of the molar ratio of acid to alcohol （n（AA）/n（MPEG））, inhibitor amount, catalyst amount, temperature, and time of esterification on the synthesis of MPEGAA. The experimental results showed that the optimal esterification conditions were as follows： n（AA）/n（MPEG）, 3.5：1; amount of hydroquinone （as an inhibitor）, 1.2%; amount of para-toluenesulfonic acid （as a catalyst）, 5.5%; reaction temperature, 95 ~C; and reaction time, 6 h. The AMPS- modified polyacrylic acid superplasticizer prepared under the optimal esterification conditions enabled the achievement and maintenance of high cement dispersibility. At an admixture amount of 0.15%, the cement paste fluidity was initially as high as 300 mm, and then decreased to 315 mm after 1 h and to 290 mm after 2 h.展开更多
A 2-acrylamide-2-methyl propylene sodium sulfonic （AMPS）-modified polyacrylic acid superplasticizer was synthesized using aqueous solution polymerization with the major monomers including the self-made active macrom...A 2-acrylamide-2-methyl propylene sodium sulfonic （AMPS）-modified polyacrylic acid superplasticizer was synthesized using aqueous solution polymerization with the major monomers including the self-made active macromers polyethylene glycol mono-methyl ether acrylate acrylic （MPEGAA）, acrylic acid （AA）, AMPS, and sodium methyl allyl sulfonate （SMAS）. The ratios of the monomers were determined using an orthogonal experiment. This research focused on the effects of the dosages of different macromers, the polymerization conditions, and the length of MPEGAA side chains on the properties of the AMPS-modified polyacrylic acid super-plasticizer. The best polymerization conditions of the AMPS-modified polyacrylic acid superplasticizer are when （n（MPEGAA）：n（SMAS）：n（AMPS）：n（AA） equals 0.1：0.1：0.2：0.65, the molecular weight of monomethoxypolyethylene glycol is 1 200, the initiator ammonium persulfate accounts for 5% of the total mass of the polymerized monomers, the polymerization temperature is 80 ~C, and the reaction time is 4 h. The AMPS-modified polyacrylic acid superplasticizer synthesized in the best conditions exhibited excellent dispersivity and dispersion retainability. When the dosage ratio was 0.24%, the initial fluidity was 400 mm and the fluidity had nearly no loss after 1 h.展开更多
Using water separation technique,acrylic acid （AA） and polyethylene glycol （PEG） 1000,of which the ratio was 1.5,were esterified and the optimum esterification ratio of 90% could be reached under the condition of ...Using water separation technique,acrylic acid （AA） and polyethylene glycol （PEG） 1000,of which the ratio was 1.5,were esterified and the optimum esterification ratio of 90% could be reached under the condition of 110 ℃×3 h.Using polyoxyethylene acrylate macromonomer （PA） prepared in the esterification,AA and sodium methylacryl sulfonate （MAS） as monomers,a copolymer which could be used as superplasticizer was prepared by free radical coolymerization in n（PA）：n（AA）：n（MAS） of 1：7：3.When the synthesis condition was 80 ℃× 5 h,the optimal dosage of initiator was 3.0%-4.0%,the fluidity of cement paste with the samples could reach 270 mm.By analyzing the effect of the content of residual small molecule sulfonic monomer on the properties of sample,n（MAS）/n（PA） was controlled in a range of 2.5-3.8.展开更多
The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to th...The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to the differences of chain sections, functional groups, eic, polyacrylic acid superplasticizer could be divided into A, B, C three parts. Among them, A chain section included sulfonic acid groups, B chain section carboxyl groups, C chain section polyester. Polyacrylic acid superplasticizers with different matching of A, B, C chain sections, different length of C chain section and different molecular weights were synthesized by acrylic acid, polyethylene glycol, sodium methyl allylsulfonate; the relation between the molecular structure and perfolxnance was also studied. The expetimental results indicate that the water-reduction ratio increases obviously with the increment of the proportion of sodium methyl allylsulfonate chain section in the molecular; the slump retention increases greatly with the increment of the proportion of acrylic acid chain section; the dispersion of cement particles increases with the increment of the chain length of polyethylene glycol; when the molecular weight is in the range of 5000, the dispersion and slump retentibity increase with the increment of the average molecular weight of polymers.展开更多
Objective:To determine the antileishmanial vaccine effectiveness of lipophosphoglycan(LPG)and polyacrylic acids(PAA)conjugates on in vivo mice models.Methods:LPG molecule was isolated and purified from large-scale Lei...Objective:To determine the antileishmanial vaccine effectiveness of lipophosphoglycan(LPG)and polyacrylic acids(PAA)conjugates on in vivo mice models.Methods:LPG molecule was isolated and purified from large-scale Leishmania donovani parasite culture.Protection efficacies of LPG alone,in combination with Freund's adjuvant,in a physical mixture and in conjugate(consisting of various LPG concentrations)with PAA,were comparatively determined by various techniques,such as cultivation with the micro-culture method,assessment of in vitro infection rates of peritoneal macrophages,determination of parasite load in liver with Leishman-Donovan Units,and detection of cytokine responses.Results:Obtained results demonstrated that the highest vaccine-mediated immune protection was provided by LPG-PAA conjugate due to all parameters investigated.According to the Leishman-Donovan Units results,the sharpest decline in parasite load was seen with a ratio of 81.17%when 35 mg LPG containing conjugate was applied.This value was 44.93%for the control group immunized only with LPG.Moreover,decreases in parasite load were 53.37%,55.2%and 65.8%for the groups immunized with 10 mg LPG containing LPG-PAA conjugate,a physical mixture of the LPG–PAA,and a mixture of LPG+Freund's adjuvant,respectively.Furthermore,cytokine results supported that Th1 mediated protection occurred when mice were immunized with LPG-PAA conjugate.Conclusions:It has been demonstrated in this study that conjugate of LPG and PAA has an antileishmanial vaccine effect against visceral leishmaniasis.In this respect,the present study may lead to new vaccine approaches based on high immunogenic LPG molecule and adjuvant polymers in fighting against Leishmania infection.展开更多
The design of advanced binders plays a critical role in stabilizing the cycling performance of large-volume-effect silicon monoxide(SiO)anodes.For the classic polyacrylic acid(PAA)binder,the self-association of-COOH g...The design of advanced binders plays a critical role in stabilizing the cycling performance of large-volume-effect silicon monoxide(SiO)anodes.For the classic polyacrylic acid(PAA)binder,the self-association of-COOH groups in PAA leads to the formation of intramolecular and intermolecular hydrogen bonds,greatly weakening the bonding force of the binder to SiO surface.However,strengthening the binder-material interaction from the perspective of binder molecular regulation poses a significant challenge.Herein,a modified PAA-Li_(x)(0.25≤x≤1)binder with prominent mechanical properties and adhesion strength is specifically synthesized for SiO anodes by quantitatively substituting the carboxylic hydrogen with lithium.The appropriate lithium substitution(x=0.25)not only effectively increases the number of hydrogen bonds between the PAA binder and SiO surface owing to charge repulsion effect between ions,but also guarantees moderate entanglement between PAA-Li_x molecular chains through the ion-dipole interaction.As such,the PAA-Li_(0.25)/SiO electrode exhibits exceptional mechanical properties and the lowest volume change,as well as the optimum cycling(1237.3 mA h g^(-1)after 100cycles at 0.1 C)and rate performance(1000.6 mA h g^(-1)at 1 C),significantly outperforming the electrode using pristine PAA binder.This work paves the way for quantitative regulation of binders at the molecular level.展开更多
The majority of cities worldwide are grappling with the challenge of dust pollution.Recently,the application potential of enzymatically induced carbonate precipitation(EICP),a novel environmentally friendly method,for...The majority of cities worldwide are grappling with the challenge of dust pollution.Recently,the application potential of enzymatically induced carbonate precipitation(EICP),a novel environmentally friendly method,for dust control has been convincingly demonstrated.However,the long-term durability of EICP treatment is consistently a significant concern,particularly in regions prone to recurrent erosion caused by rainfall.As a result,the erosion durability of the EICP-treated dust soils requires further investigation.To address this,Polyacrylic acid(PAA)was added to the cementation solution in this study as the combined PAA and EICP treatment for dust control.The results showed that the addition of PAA slightly affected urea degradation;however,the combined PAA and EICP treatment significantly improved surface strength from 300 kPa to 500 kPa,especially for the wind-erosion resistance compared with the EICP treatment alone.The surface strength of samples treated with the combined PAA and EICP still exhibited a decrease due to repeated rainfall erosion,along with a reduction in calcium carbonate(CaCO_(3))contents.Nevertheless,the decreasing slopes of surface strength(k=13.434,14.002,or 14.186)in response to repeated rainfall for EICP-PAA-treated slopes were much smaller than those for EICP-treated samples(k=14.271),as well as the decreasing slopes of CaCO_(3)contents,which suggested the slopes with the combined treatment had significantly improved durability.By comparing the cementation effect and the influence of repeated rainfalls on treated dust samples,the EICP-PAA(50 g/L)treatment achieved better dust control effects.Overall,the combined treatment of EICP-PAA shows promising potential for effectively suppressing dust generation and enhancing erosion durability.展开更多
Bacterial cellulose/polyacrylic acid (BC/PAA) pH-responsive hydrogels were prepared by free-radical polymerization (in situ) using BC as the raw material and AA as the monomer. The hydrogels were loaded with curcumin ...Bacterial cellulose/polyacrylic acid (BC/PAA) pH-responsive hydrogels were prepared by free-radical polymerization (in situ) using BC as the raw material and AA as the monomer. The hydrogels were loaded with curcumin (Cur) to prepare pH-responsive intelligent medical dressings. The preparation process of the hydrogels was optimized by a single factor and response surface experiment using their swelling degree as an index. The structures of BC/PAA pH-responsive hydrogels were characterized by scanning electron microscope (SEM), Fourier Transform Infrared spectrometer (FTIR), X-ray diffraction (XRD), and tensile tester, and the swelling properties, mechanical properties, bacteriostatic properties, and drug release behavior were investigated. The results showed that the BC/PAA pH-responsive hydrogel has a three-dimensional network structure with the swelling rate up to 1600 g/g, compressive strength of up to 8 KPa, and good mechanical properties, and the drug release behavior was in line with the logistic dynamics model, and it has good inhibitory effects on common pathogens of wound infection: E. coli, S. aureus, and P. aeruginosa.展开更多
Lithium-sulfur(Li-S)batteries with high theoretical capacity and energy density need to solve problems such as the high decomposition energy barrier of Li_(2)S and large volume change of sulfur in the charging process...Lithium-sulfur(Li-S)batteries with high theoretical capacity and energy density need to solve problems such as the high decomposition energy barrier of Li_(2)S and large volume change of sulfur in the charging process caused by the shuttle effect before practical application.Herein,a green synthesis method is used to prepare polyacrylic acid(PAA)superabsorbent material,and then the pyrolyzed PAA(P/PAA)material is obtained as the positive electrode of Li-S battery.Density functional calculation reveals that the oxygen self-doping pyrolyzed polyacrylic acid(P/PAA)delivered stronger binding energy toward Li2S species in carbonyl C=O than that of graphite powder(GP)which are-1.58 eV and-1.02 eV,respectively.Coupled with the distribution of relaxation time analysis and the in-situ electrochemical impedance approach,it is further demonstrated that the designed P/PAA as sulfur host plays a physical/chemical adsorption dual function in maintaining the stability and rate performance of batteries.With an initial discharge capacity of 1258 mAh/g at 0.1 C and a minimal capacity decline of 0.05%per cycle even after 800 cycles at 0.5 C,the produced cathode demonstrated outstanding electrochemical performance.The average Coulombic efficiency is nearly 100%.The P/PAA electrodes may typically retain 96%of their capacity while declining on average only 0.033%per cycle after 130 cycles at 3 C.This effort provides a new method for the future development of heteroatomic self-doping superabsorbent with promising adsorption properties for polysulfides as cathode materials of Li-S batteries.展开更多
Dynamic behaviors on polyacrylic acid (PAA) gels and mass (small molecules) transports in the gels have been studied mainly by dynamic light scattering (DLS). The cross-linking degree (fc), monomer concentration (Cm)...Dynamic behaviors on polyacrylic acid (PAA) gels and mass (small molecules) transports in the gels have been studied mainly by dynamic light scattering (DLS). The cross-linking degree (fc), monomer concentration (Cm) and temperature of the gels have significant influences on its dynamic behavior and mass transport in the gels. The increase of fc leads to decrease of the mesh sizes of the gels, thus the obstacle of the gels for mass transport is increased. As a result, small molecular diffusion Dk in the gels is decreased. So even if for small molecules, the Dk also is influenced.展开更多
In situ interferometry was used to investigate the gelation process of polyacrylic acid (PAA) gels. The basic principle of the in situ interferometry technique is illustrated. It can give sufficient information for no...In situ interferometry was used to investigate the gelation process of polyacrylic acid (PAA) gels. The basic principle of the in situ interferometry technique is illustrated. It can give sufficient information for non-destructive and successful investigation of the whole gelation process. The effect of initiator concentration on the gelation process was studied. The polymerization rate of AA increases with increasing initiator concentration. The error arising from the thermal effect in the gelation process can be neglected.展开更多
A self-made 2-acrylamide-2-methyl propylene sulfonic （AMPS）-modified polyacrylic acid superplasticizer and two other commercially available superplasticizers with different molecular structures are used in this stud...A self-made 2-acrylamide-2-methyl propylene sulfonic （AMPS）-modified polyacrylic acid superplasticizer and two other commercially available superplasticizers with different molecular structures are used in this study to investigate the effect of an AMPS-modified polyacrylic acid superplasticizer on the properties of concrete materials. In the experiments, initial and 1.5 h slumps over time after admixtion are determined by adding different dosages of three superplasticizers into the premixed concrete to characterize the slump loss resistance of the premixed concrete. The water-reducing rates of three different types of concrete are determined to characterize the water-reducing capacity of the concrete with each superplasticizer. The 3, 7 and 28 d compressive strength is determined to characterize the mechanical properties of the concrete with each superplasticizer. In the meanwhile, 1, 1.5 and 2.0 h slump loss rates over time after admixtion are determined by adding different dosages of the three superplasticizers into the high-performance concrete （HPC） to characterize the slump loss resistance of HPC. The 7, 28, 60 and 90 d compressive strength is determined to characterize the compressive properties of HPC with each superplasticizer. The dry shrinkage rates of three different types of HPC are determined with each superplasticizer. Electric flux after standard curing for 56 d and chloride ion diffusion coefficient after curing for 28 d of I-IPC are determined to characterize the impermeability of HPC with each superplasticizer. The cross-section was examined using a scanning electron microscopy （SEM） system. Results demonstrate that the AMPS-modified polyacrylic acid superplasticizer has better water-reducing effect and slump than the two commercially available polyacrylie acid superplasticizers. The AMPS-modified polyacrylic acid superplasticizer also shows significant improvement of the compressive strength, especially in comprehensive performance of HPC. In conclusion, the AMPS-modified polyacrylic acid superplastieizer is particularly suitable for the preparation of HPC.展开更多
The development of sustainable biomaterials has recently attracted great interest in the fields of flexible electronics and biosensing hydrogels.Hydrogels are a class of three-dimensional spatial network structure,and...The development of sustainable biomaterials has recently attracted great interest in the fields of flexible electronics and biosensing hydrogels.Hydrogels are a class of three-dimensional spatial network structure,and their structure and shape can exhibit reversible or noticeable responses to various stimuli,making them a popular choice for flexible electronic materials in recent years.Acrylic hydrogels,which possess a rich carboxylate network,can provide significant sensing and actuation properties to the hydrogels.They are often synthesized through the co-polymerization of their monomers and cross-linking agents,and they can be combined with naturally occurring biopolymers such as cellulose and chitosan to enhance biocompatibility.In this paper,we re-view the compounding methods and preparation process technologies of functionalized acrylic hydrogels and the application of polyacrylic acid(PAA)bioproducts in various fields.Finally,we review the current challenges and future directions for acrylic hydrogel prepared sensors and their applications.展开更多
Slurries with high solid loading and low apparent viscosity are critical for spontaneous coagulation casting(SCC)and other in situ slurry solidification techniques.This work evaluated polyacrylic acid(PA)with a low mo...Slurries with high solid loading and low apparent viscosity are critical for spontaneous coagulation casting(SCC)and other in situ slurry solidification techniques.This work evaluated polyacrylic acid(PA)with a low molecular weight modified as a superior dispersant(M-PA)to increase the versatility and applicability of SCC,which traditionally employs Isobam 600AF as a dispersant in combination with Isobam 104.Varying the ratio of M-PA to Isobam 104 increased the solid loading of the alumina slurry—formulated with a commercial powder(D_(50)=0.45μm)—from 56 to 58 vol%.The relative density of the alumina green body increased from 62.0%to 67.0%.The ceramics derived from a 56 vol%solid loading slurry,when sintered at 1550℃,exhibited a relative density of 98.7%,a Vickers hardness of 17.3 GPa,and a flexural strength of 583 MPa,surpassing those of ceramics prepared with other dispersants.The ceramics derived from a 58 vol%solid loading slurry,when sintered at 1500℃,exhibited a relative density of 98.9%and a Vickers hardness of 17.8 GPa.These findings demonstrate the potential of M-PA to broaden the applicability of SCC and suggest that the strategy of using a low-molecular-weight dispersant may enable the fabrication of high-density green bodies through SCC,resulting in high mechanical properties of ceramics under low sintering temperatures.展开更多
Surface-enhanced Raman spectroscopy （SERS） is a fast analytical technique for trace chemicals; however, it requires the active SERS-substrates to adsorb analytes, thus limiting target species to those with the desir...Surface-enhanced Raman spectroscopy （SERS） is a fast analytical technique for trace chemicals; however, it requires the active SERS-substrates to adsorb analytes, thus limiting target species to those with the desired affinity for substrates. Here we present networked polyacrylic acid sodium salt （PAAS） film entrapped Ag-nanocubes （denoted as Ag-nanocubes@PAAS） as an effective SERS-substrate for analytes with and without high affinity. Once the analyte aqueous solution is cast on the dry Ag-nanocubes@PAAS substrate, the bibulous PAAS becomes swollen forcing the Ag-nanocubes loose, while the analytes diffuse in the interstices among the Ag-nanocubes. When dried, the PAAS shrinks and pulls the Ag-nanocubes back to their previous aggregated state, while the PAAS network ＂detains＂ the analytes in the small gaps between the Ag-nanocubes for SERS detection. The strategy has been proven effective for not only single- analytes but also multi-analytes without strong affinity for Ag, showing its potential in SERS-based simultaneous multi-analyte detection of both adsorbable and non-adsorbable pollutants in the environment.展开更多
Currently,it is a challenge to develop hemostatic materials with high water absorption capacity and anti-fatigue properties for quickly preventing massive hemorrhage from arteries and visceral organs.A series of polya...Currently,it is a challenge to develop hemostatic materials with high water absorption capacity and anti-fatigue properties for quickly preventing massive hemorrhage from arteries and visceral organs.A series of polyacrylic acid/chitosan(PAA/CS)cryogels were prepared by a cryostructurization technique to improve mechanical performance and hemostatic efficiency of chitosan(CS).In this system,the chemically cross-linked PAA network was used as a framework to improve water absorption behaviors and mechanical strength.The CS network was co-blended by hydrogen bonding and electrostatic interactions,both of which synergistically promoted hemostasis.These cryogels had high porosity(>94%),rapid water absorption rate(<3 s),high blood absorption capacity(>2000%),outstanding mechanical strength,and fatigue resistance.Moreover,the results of cytotoxicity and hemolysis demonstrated that the cryogels had good biocompatibility.Notably,the PAA/CS cryogels exhibited superior whole blood coagulation ability and red blood cell and platelet adhesion ability compared to those of commercial hemostatic dressing(gauze,gelatin sponges,and CS sponges).Based on these results,mouse femoral artery hemorrhage models and liver hemorrhage models were prepared to investigate the hemostatic ability of the prepared PAA/CS cryogels.Results suggested that the hemostatic ability of PAA5/CS cryogels was superior to that of commercial hemostatic materials.Therefore,the PAA/CS cryogels showed potential application in preventing massive hemorrhage from arteries and visceral organs.展开更多
基金funding supports of the National Natural Science Foundation of China(52402315,52172244,51874104,and 52172190)the"Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang"(2023R01007)the Zhejiang Provincial"Jianbing"and"Lingyan"R&D Programs(Grant No.2024C01262)。
文摘Polyacrylic acid(PAA)-based binders have been demonstrated to significantly enhance the cycling stability of pure silicon(Si)anodes compared to other binder types.However,there is a notable lack of systematic and in-depth investigation into the relationship between the molecular weight(MW)of PAA and its performance in pure Si anodes,leading to an absence of reliable theoretical guidance for designing and optimizing of PAA-based binders for these anodes.Herein,we select a series of PAA with varying MWs as binders for Si nanoparticle(SiNP)anodes to systematically identify the optimal MW of PAA for enhancing the electrochemical performance of SiNP anodes.The actual MWs of the various PAA were confirmed by gel permeation chromatography to accurately establish the relationship between MW and binder performance.Within an ultrawide weight average molecular weight(M_(w))range of 35.9-4850 kDa,we identify that the PAA binder with a M_(w)of 1250 kDa(PAA125)exhibits the strongest mechanical strength and the highest adhesion strength,attributed to its favorable molecular chain orientation and robust interchain interactions.These characteristics enable the SiNP anodes utilizing PAA125 to maintain the best interfacial chemistry and bulk mechanical structure stability,leading to optimal electrochemical performance.Notably,the enhancement in cycling stability of SiNP anode by PAA125 under practical application conditions is further validated by the 1.1 Ah LLNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/SiNP@PAA125 pouch cell.
基金supported by the LingChuang Re-search Project of China National Nuclear Corporation。
文摘The effect of polyacrylic acid(PAA)on the corrosion behavior of Alloy 690 in simulated pressurized water reactor secondary water was investigated.The duplex oxide film structure,consisting of a Ni-rich outer layer and a Cr-rich inner layer,was maintained regardless of PAA presence.PAA inhibited the growth of outer Ni-rich particles while promoting Cr enrichment in the inner layer and inducing its amorphization,both enhancing oxidation resistance.However,excess PAA(≥500 ppb)suppressed protective oxide formation during initial oxidation,leading to oxygen penetration into the matrix.A PAA concentration of around 250 ppb is considered optimal for steam generators,as it provides the benefits of PAA without adverse effects on the alloy.
基金Funded by the Fujian Education Department(Nos.JA11329,JA12412)Quanzhou(Fujian)Technology Research and Development Program(Nos.2013Z158,2013Z47,2010G7)
文摘A self-made AMPS-modified polyacrylic acid superplasticizer and two others of the same type but with different molecular structures, which are commercially available, are used in this study to investigate the effect of a 2-acrylamide-2-methyl propylene sulfonic （AMPS）-modified polyacrylic acid superplasticizer on the properties of cement-based materials. In the experiments, initial fluidity, 1 and 2 h fluidity over time after admixtion, bleeding rate of the net cement mortar, and adsorption capacity and rate of cement particles are determined by adding different dosages of the three superplasticizers into the cement paste to characterize the dispersivity and the dispersion retention capability of each superplasticizer. Water-reducing rates of three kinds of mortars are simultaneously determined to characterize the water-reducing capacity of each superplasticizer, as well as the 3 and 28 d compressive strengths to characterize the compression resistance. Results show that water-reducing effect and fluidity better maintain the capability of the AMPS-modified polyacrylic acid superplasticizer than the two commercially available polyacrylic acid superplasticizers, and the compressive strengths after 3 and 28 d show significant growth. In conclusion, the effects of water reduction and strengthening of the AMPS-modified polyacrylic acid superplasticizer are evidently better than those of the two commercially available polyacrylic acid superplasticizers.
基金Funded by the Fujian Education Department(Nos.JA11329,JA12412)the Quanzhou(Fujian)Technology Research and Development Program(No.2010G7)
文摘A macromer, methoxypolyethylene glycol acrylate （MPEGAA）, was synthesized by direct esterification using methoxypolyethylene glycol （MPEG-1200） and acrylic acid （AA） as the main materials. MPEGAA was then used to prepare a polyacrylic acid superplasticizer modified with 2-acrylamido-2- methylpropane sulfonic acid （AMPS）. A single-factor test was performed to investigate the effects of the molar ratio of acid to alcohol （n（AA）/n（MPEG））, inhibitor amount, catalyst amount, temperature, and time of esterification on the synthesis of MPEGAA. The experimental results showed that the optimal esterification conditions were as follows： n（AA）/n（MPEG）, 3.5：1; amount of hydroquinone （as an inhibitor）, 1.2%; amount of para-toluenesulfonic acid （as a catalyst）, 5.5%; reaction temperature, 95 ~C; and reaction time, 6 h. The AMPS- modified polyacrylic acid superplasticizer prepared under the optimal esterification conditions enabled the achievement and maintenance of high cement dispersibility. At an admixture amount of 0.15%, the cement paste fluidity was initially as high as 300 mm, and then decreased to 315 mm after 1 h and to 290 mm after 2 h.
基金Funded by Fujian Education Department(Nos.JA11329,JA12412)Quanzhou (Fujian) Technology Research and Development Program(No.2010G7)
文摘A 2-acrylamide-2-methyl propylene sodium sulfonic （AMPS）-modified polyacrylic acid superplasticizer was synthesized using aqueous solution polymerization with the major monomers including the self-made active macromers polyethylene glycol mono-methyl ether acrylate acrylic （MPEGAA）, acrylic acid （AA）, AMPS, and sodium methyl allyl sulfonate （SMAS）. The ratios of the monomers were determined using an orthogonal experiment. This research focused on the effects of the dosages of different macromers, the polymerization conditions, and the length of MPEGAA side chains on the properties of the AMPS-modified polyacrylic acid super-plasticizer. The best polymerization conditions of the AMPS-modified polyacrylic acid superplasticizer are when （n（MPEGAA）：n（SMAS）：n（AMPS）：n（AA） equals 0.1：0.1：0.2：0.65, the molecular weight of monomethoxypolyethylene glycol is 1 200, the initiator ammonium persulfate accounts for 5% of the total mass of the polymerized monomers, the polymerization temperature is 80 ~C, and the reaction time is 4 h. The AMPS-modified polyacrylic acid superplasticizer synthesized in the best conditions exhibited excellent dispersivity and dispersion retainability. When the dosage ratio was 0.24%, the initial fluidity was 400 mm and the fluidity had nearly no loss after 1 h.
基金Funded by the Research Item from Ministry of Communications Tech-nology Project(No. 2007319811130)
文摘Using water separation technique,acrylic acid （AA） and polyethylene glycol （PEG） 1000,of which the ratio was 1.5,were esterified and the optimum esterification ratio of 90% could be reached under the condition of 110 ℃×3 h.Using polyoxyethylene acrylate macromonomer （PA） prepared in the esterification,AA and sodium methylacryl sulfonate （MAS） as monomers,a copolymer which could be used as superplasticizer was prepared by free radical coolymerization in n（PA）：n（AA）：n（MAS） of 1：7：3.When the synthesis condition was 80 ℃× 5 h,the optimal dosage of initiator was 3.0%-4.0%,the fluidity of cement paste with the samples could reach 270 mm.By analyzing the effect of the content of residual small molecule sulfonic monomer on the properties of sample,n（MAS）/n（PA） was controlled in a range of 2.5-3.8.
基金the Western Region Traffic Construction Technology Program of the Ministry of Communications of China(No.2007-088)
文摘The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to the differences of chain sections, functional groups, eic, polyacrylic acid superplasticizer could be divided into A, B, C three parts. Among them, A chain section included sulfonic acid groups, B chain section carboxyl groups, C chain section polyester. Polyacrylic acid superplasticizers with different matching of A, B, C chain sections, different length of C chain section and different molecular weights were synthesized by acrylic acid, polyethylene glycol, sodium methyl allylsulfonate; the relation between the molecular structure and perfolxnance was also studied. The expetimental results indicate that the water-reduction ratio increases obviously with the increment of the proportion of sodium methyl allylsulfonate chain section in the molecular; the slump retention increases greatly with the increment of the proportion of acrylic acid chain section; the dispersion of cement particles increases with the increment of the chain length of polyethylene glycol; when the molecular weight is in the range of 5000, the dispersion and slump retentibity increase with the increment of the average molecular weight of polymers.
基金financially supported by TUBITAK(1085170SBAG–4007)
文摘Objective:To determine the antileishmanial vaccine effectiveness of lipophosphoglycan(LPG)and polyacrylic acids(PAA)conjugates on in vivo mice models.Methods:LPG molecule was isolated and purified from large-scale Leishmania donovani parasite culture.Protection efficacies of LPG alone,in combination with Freund's adjuvant,in a physical mixture and in conjugate(consisting of various LPG concentrations)with PAA,were comparatively determined by various techniques,such as cultivation with the micro-culture method,assessment of in vitro infection rates of peritoneal macrophages,determination of parasite load in liver with Leishman-Donovan Units,and detection of cytokine responses.Results:Obtained results demonstrated that the highest vaccine-mediated immune protection was provided by LPG-PAA conjugate due to all parameters investigated.According to the Leishman-Donovan Units results,the sharpest decline in parasite load was seen with a ratio of 81.17%when 35 mg LPG containing conjugate was applied.This value was 44.93%for the control group immunized only with LPG.Moreover,decreases in parasite load were 53.37%,55.2%and 65.8%for the groups immunized with 10 mg LPG containing LPG-PAA conjugate,a physical mixture of the LPG–PAA,and a mixture of LPG+Freund's adjuvant,respectively.Furthermore,cytokine results supported that Th1 mediated protection occurred when mice were immunized with LPG-PAA conjugate.Conclusions:It has been demonstrated in this study that conjugate of LPG and PAA has an antileishmanial vaccine effect against visceral leishmaniasis.In this respect,the present study may lead to new vaccine approaches based on high immunogenic LPG molecule and adjuvant polymers in fighting against Leishmania infection.
基金supported by the National Natural Science Foundation of China (Grant Nos.92372101,52162036 and 21875155)the Fundamental Research Funds for the Central Universities (Grant Nos.20720220010)the National Key Research and Development Program of China (Grant Nos.2021YFA1201502)。
文摘The design of advanced binders plays a critical role in stabilizing the cycling performance of large-volume-effect silicon monoxide(SiO)anodes.For the classic polyacrylic acid(PAA)binder,the self-association of-COOH groups in PAA leads to the formation of intramolecular and intermolecular hydrogen bonds,greatly weakening the bonding force of the binder to SiO surface.However,strengthening the binder-material interaction from the perspective of binder molecular regulation poses a significant challenge.Herein,a modified PAA-Li_(x)(0.25≤x≤1)binder with prominent mechanical properties and adhesion strength is specifically synthesized for SiO anodes by quantitatively substituting the carboxylic hydrogen with lithium.The appropriate lithium substitution(x=0.25)not only effectively increases the number of hydrogen bonds between the PAA binder and SiO surface owing to charge repulsion effect between ions,but also guarantees moderate entanglement between PAA-Li_x molecular chains through the ion-dipole interaction.As such,the PAA-Li_(0.25)/SiO electrode exhibits exceptional mechanical properties and the lowest volume change,as well as the optimum cycling(1237.3 mA h g^(-1)after 100cycles at 0.1 C)and rate performance(1000.6 mA h g^(-1)at 1 C),significantly outperforming the electrode using pristine PAA binder.This work paves the way for quantitative regulation of binders at the molecular level.
基金supported by the University Grants Committee(UGC),The Hong Kong Polytechnic University(grant number P0043090)the National Natural Science Foundation of China(grant number 51578147)+1 种基金the Science and Technology Department of Ningxia(grant number 2020BFG02014)Transportation Department of Ningxia(grant number 202000173).
文摘The majority of cities worldwide are grappling with the challenge of dust pollution.Recently,the application potential of enzymatically induced carbonate precipitation(EICP),a novel environmentally friendly method,for dust control has been convincingly demonstrated.However,the long-term durability of EICP treatment is consistently a significant concern,particularly in regions prone to recurrent erosion caused by rainfall.As a result,the erosion durability of the EICP-treated dust soils requires further investigation.To address this,Polyacrylic acid(PAA)was added to the cementation solution in this study as the combined PAA and EICP treatment for dust control.The results showed that the addition of PAA slightly affected urea degradation;however,the combined PAA and EICP treatment significantly improved surface strength from 300 kPa to 500 kPa,especially for the wind-erosion resistance compared with the EICP treatment alone.The surface strength of samples treated with the combined PAA and EICP still exhibited a decrease due to repeated rainfall erosion,along with a reduction in calcium carbonate(CaCO_(3))contents.Nevertheless,the decreasing slopes of surface strength(k=13.434,14.002,or 14.186)in response to repeated rainfall for EICP-PAA-treated slopes were much smaller than those for EICP-treated samples(k=14.271),as well as the decreasing slopes of CaCO_(3)contents,which suggested the slopes with the combined treatment had significantly improved durability.By comparing the cementation effect and the influence of repeated rainfalls on treated dust samples,the EICP-PAA(50 g/L)treatment achieved better dust control effects.Overall,the combined treatment of EICP-PAA shows promising potential for effectively suppressing dust generation and enhancing erosion durability.
文摘Bacterial cellulose/polyacrylic acid (BC/PAA) pH-responsive hydrogels were prepared by free-radical polymerization (in situ) using BC as the raw material and AA as the monomer. The hydrogels were loaded with curcumin (Cur) to prepare pH-responsive intelligent medical dressings. The preparation process of the hydrogels was optimized by a single factor and response surface experiment using their swelling degree as an index. The structures of BC/PAA pH-responsive hydrogels were characterized by scanning electron microscope (SEM), Fourier Transform Infrared spectrometer (FTIR), X-ray diffraction (XRD), and tensile tester, and the swelling properties, mechanical properties, bacteriostatic properties, and drug release behavior were investigated. The results showed that the BC/PAA pH-responsive hydrogel has a three-dimensional network structure with the swelling rate up to 1600 g/g, compressive strength of up to 8 KPa, and good mechanical properties, and the drug release behavior was in line with the logistic dynamics model, and it has good inhibitory effects on common pathogens of wound infection: E. coli, S. aureus, and P. aeruginosa.
基金the financial support of the National Natural Science Foundation of China(Nos.22271106,21501175 and 2227518)the Natural Science Foundation of Fujian Province(No.2022Y0071)the Leading Project Foundation of Science Department of Fujian Province(No.2023H0045)。
文摘Lithium-sulfur(Li-S)batteries with high theoretical capacity and energy density need to solve problems such as the high decomposition energy barrier of Li_(2)S and large volume change of sulfur in the charging process caused by the shuttle effect before practical application.Herein,a green synthesis method is used to prepare polyacrylic acid(PAA)superabsorbent material,and then the pyrolyzed PAA(P/PAA)material is obtained as the positive electrode of Li-S battery.Density functional calculation reveals that the oxygen self-doping pyrolyzed polyacrylic acid(P/PAA)delivered stronger binding energy toward Li2S species in carbonyl C=O than that of graphite powder(GP)which are-1.58 eV and-1.02 eV,respectively.Coupled with the distribution of relaxation time analysis and the in-situ electrochemical impedance approach,it is further demonstrated that the designed P/PAA as sulfur host plays a physical/chemical adsorption dual function in maintaining the stability and rate performance of batteries.With an initial discharge capacity of 1258 mAh/g at 0.1 C and a minimal capacity decline of 0.05%per cycle even after 800 cycles at 0.5 C,the produced cathode demonstrated outstanding electrochemical performance.The average Coulombic efficiency is nearly 100%.The P/PAA electrodes may typically retain 96%of their capacity while declining on average only 0.033%per cycle after 130 cycles at 3 C.This effort provides a new method for the future development of heteroatomic self-doping superabsorbent with promising adsorption properties for polysulfides as cathode materials of Li-S batteries.
基金Project 29774011 was supported by the National Natural Science Foundation of China.
文摘Dynamic behaviors on polyacrylic acid (PAA) gels and mass (small molecules) transports in the gels have been studied mainly by dynamic light scattering (DLS). The cross-linking degree (fc), monomer concentration (Cm) and temperature of the gels have significant influences on its dynamic behavior and mass transport in the gels. The increase of fc leads to decrease of the mesh sizes of the gels, thus the obstacle of the gels for mass transport is increased. As a result, small molecular diffusion Dk in the gels is decreased. So even if for small molecules, the Dk also is influenced.
基金The National Natural Science Foundation of China (Grant No. 29774036 and 29904007) and PPLAS foundation of the Chinese Academy of Sciences are gratefully acknowledged for the financial support to this work.
文摘In situ interferometry was used to investigate the gelation process of polyacrylic acid (PAA) gels. The basic principle of the in situ interferometry technique is illustrated. It can give sufficient information for non-destructive and successful investigation of the whole gelation process. The effect of initiator concentration on the gelation process was studied. The polymerization rate of AA increases with increasing initiator concentration. The error arising from the thermal effect in the gelation process can be neglected.
基金Funded by the Fujian Education Department(Nos.JA11329,JA12412)Quanzhou(Fujian)Technology Research and Development Program(Nos.2013Z47,2013Z158,2010G7)
文摘A self-made 2-acrylamide-2-methyl propylene sulfonic （AMPS）-modified polyacrylic acid superplasticizer and two other commercially available superplasticizers with different molecular structures are used in this study to investigate the effect of an AMPS-modified polyacrylic acid superplasticizer on the properties of concrete materials. In the experiments, initial and 1.5 h slumps over time after admixtion are determined by adding different dosages of three superplasticizers into the premixed concrete to characterize the slump loss resistance of the premixed concrete. The water-reducing rates of three different types of concrete are determined to characterize the water-reducing capacity of the concrete with each superplasticizer. The 3, 7 and 28 d compressive strength is determined to characterize the mechanical properties of the concrete with each superplasticizer. In the meanwhile, 1, 1.5 and 2.0 h slump loss rates over time after admixtion are determined by adding different dosages of the three superplasticizers into the high-performance concrete （HPC） to characterize the slump loss resistance of HPC. The 7, 28, 60 and 90 d compressive strength is determined to characterize the compressive properties of HPC with each superplasticizer. The dry shrinkage rates of three different types of HPC are determined with each superplasticizer. Electric flux after standard curing for 56 d and chloride ion diffusion coefficient after curing for 28 d of I-IPC are determined to characterize the impermeability of HPC with each superplasticizer. The cross-section was examined using a scanning electron microscopy （SEM） system. Results demonstrate that the AMPS-modified polyacrylic acid superplasticizer has better water-reducing effect and slump than the two commercially available polyacrylie acid superplasticizers. The AMPS-modified polyacrylic acid superplasticizer also shows significant improvement of the compressive strength, especially in comprehensive performance of HPC. In conclusion, the AMPS-modified polyacrylic acid superplastieizer is particularly suitable for the preparation of HPC.
基金supported by Young Scientists Fund of the National Natural Science Foundation of China(No.32101459)Jiangsu Agricultural Science and Technology Innovation Fund(No.CX(22)3171)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The development of sustainable biomaterials has recently attracted great interest in the fields of flexible electronics and biosensing hydrogels.Hydrogels are a class of three-dimensional spatial network structure,and their structure and shape can exhibit reversible or noticeable responses to various stimuli,making them a popular choice for flexible electronic materials in recent years.Acrylic hydrogels,which possess a rich carboxylate network,can provide significant sensing and actuation properties to the hydrogels.They are often synthesized through the co-polymerization of their monomers and cross-linking agents,and they can be combined with naturally occurring biopolymers such as cellulose and chitosan to enhance biocompatibility.In this paper,we re-view the compounding methods and preparation process technologies of functionalized acrylic hydrogels and the application of polyacrylic acid(PAA)bioproducts in various fields.Finally,we review the current challenges and future directions for acrylic hydrogel prepared sensors and their applications.
基金supported by the National Natural Science Foundation of China(Nos.52130207 and U23A6014)。
文摘Slurries with high solid loading and low apparent viscosity are critical for spontaneous coagulation casting(SCC)and other in situ slurry solidification techniques.This work evaluated polyacrylic acid(PA)with a low molecular weight modified as a superior dispersant(M-PA)to increase the versatility and applicability of SCC,which traditionally employs Isobam 600AF as a dispersant in combination with Isobam 104.Varying the ratio of M-PA to Isobam 104 increased the solid loading of the alumina slurry—formulated with a commercial powder(D_(50)=0.45μm)—from 56 to 58 vol%.The relative density of the alumina green body increased from 62.0%to 67.0%.The ceramics derived from a 56 vol%solid loading slurry,when sintered at 1550℃,exhibited a relative density of 98.7%,a Vickers hardness of 17.3 GPa,and a flexural strength of 583 MPa,surpassing those of ceramics prepared with other dispersants.The ceramics derived from a 58 vol%solid loading slurry,when sintered at 1500℃,exhibited a relative density of 98.9%and a Vickers hardness of 17.8 GPa.These findings demonstrate the potential of M-PA to broaden the applicability of SCC and suggest that the strategy of using a low-molecular-weight dispersant may enable the fabrication of high-density green bodies through SCC,resulting in high mechanical properties of ceramics under low sintering temperatures.
文摘Surface-enhanced Raman spectroscopy （SERS） is a fast analytical technique for trace chemicals; however, it requires the active SERS-substrates to adsorb analytes, thus limiting target species to those with the desired affinity for substrates. Here we present networked polyacrylic acid sodium salt （PAAS） film entrapped Ag-nanocubes （denoted as Ag-nanocubes@PAAS） as an effective SERS-substrate for analytes with and without high affinity. Once the analyte aqueous solution is cast on the dry Ag-nanocubes@PAAS substrate, the bibulous PAAS becomes swollen forcing the Ag-nanocubes loose, while the analytes diffuse in the interstices among the Ag-nanocubes. When dried, the PAAS shrinks and pulls the Ag-nanocubes back to their previous aggregated state, while the PAAS network ＂detains＂ the analytes in the small gaps between the Ag-nanocubes for SERS detection. The strategy has been proven effective for not only single- analytes but also multi-analytes without strong affinity for Ag, showing its potential in SERS-based simultaneous multi-analyte detection of both adsorbable and non-adsorbable pollutants in the environment.
基金supported by the National Natural Science Foundation of China(Grant Nos.U20A20261,31870948,31971250,and 52073205)Natural Science Foundation of Tianjin(Grant No.20JCYBJC00660)。
文摘Currently,it is a challenge to develop hemostatic materials with high water absorption capacity and anti-fatigue properties for quickly preventing massive hemorrhage from arteries and visceral organs.A series of polyacrylic acid/chitosan(PAA/CS)cryogels were prepared by a cryostructurization technique to improve mechanical performance and hemostatic efficiency of chitosan(CS).In this system,the chemically cross-linked PAA network was used as a framework to improve water absorption behaviors and mechanical strength.The CS network was co-blended by hydrogen bonding and electrostatic interactions,both of which synergistically promoted hemostasis.These cryogels had high porosity(>94%),rapid water absorption rate(<3 s),high blood absorption capacity(>2000%),outstanding mechanical strength,and fatigue resistance.Moreover,the results of cytotoxicity and hemolysis demonstrated that the cryogels had good biocompatibility.Notably,the PAA/CS cryogels exhibited superior whole blood coagulation ability and red blood cell and platelet adhesion ability compared to those of commercial hemostatic dressing(gauze,gelatin sponges,and CS sponges).Based on these results,mouse femoral artery hemorrhage models and liver hemorrhage models were prepared to investigate the hemostatic ability of the prepared PAA/CS cryogels.Results suggested that the hemostatic ability of PAA5/CS cryogels was superior to that of commercial hemostatic materials.Therefore,the PAA/CS cryogels showed potential application in preventing massive hemorrhage from arteries and visceral organs.
