With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complicatio...With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complications.Currently,reagents based on modified natural polymers(which are naturally occurring compounds)and synthetic polymers(SPs)which are polymeric compounds created industrially,are widely used to prevent emerging complications in the drilling process.However,compared to modified natural polymers,SPs form a family of high-molecular-weight compounds that are fully synthesized by undergoing chemical polymerization reactions.SPs provide substantial flexibility in their design.Moreover,their size and chemical composition can be adjusted to provide properties for nearly all the functional objectives of drilling fluids.They can be classified based on chemical ingredients,type of reaction,and their responses to heating.However,some of SPs,due to their structural characteristics,have a high cost,a poor temperature and salt resistance in drilling fluids,and degradation begins when the temperature reaches 130℃.These drawbacks prevent SP use in some medium and deep wells.Thus,this review addresses the historical development,the characteristics,manufacturing methods,classification,and the applications of SPs in drilling fluids.The contributions of SPs as additives to drilling fluids to enhance rheology,filtrate generation,carrying of cuttings,fluid lubricity,and clay/shale stability are explained in detail.The mechanisms,impacts,and advances achieved when SPs are added to drilling fluids are also described.The typical challenges encountered by SPs when deployed in drilling fluids and their advantages and drawbacks are also discussed.Economic issues also impact the applications of SPs in drilling fluids.Consequently,the cost of the most relevant SPs,and the monomers used in their synthesis,are assessed.Environmental impacts of SPs when deployed in drilling fluids,and their manufacturing processes are identified,together with advances in SP-treatment methods aimed at reducing those impacts.Recommendations for required future research addressing SP property and performance gaps are provided.展开更多
The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of...The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.展开更多
Acid loss and plasticization of phosphoric acid(PA)-doped high-temperature polymer electrolyte membranes(HT-PEMs)are critical limitations to their practical application in fuel cells.To overcome these barriers,poly(te...Acid loss and plasticization of phosphoric acid(PA)-doped high-temperature polymer electrolyte membranes(HT-PEMs)are critical limitations to their practical application in fuel cells.To overcome these barriers,poly(terphenyl piperidinium)s constructed from the m-and p-isomers of terphenyl were synthesized to regulate the microstructure of the membrane.Highly rigid p-terphenyl units prompt the formation of moderate PA aggregates,where the ion-pair interaction between piperidinium and biphosphate is reinforced,leading to a reduction in the plasticizing effect.As a result,there are trade-offs between the proton conductivity,mechanical strength,and PA retention of the membranes with varied m/p-isomer ratios.The designed PA-doped PTP-20m membrane exhibits superior ionic conductivity,good mechanical strength,and excellent PA retention over a wide range of temperature(80–160°C)as well as satisfactory resistance to harsh accelerated aging tests.As a result,the membrane presents a desirable combination of performance(1.462 W cm^(-2) under the H_(2)/O_(2)condition,which is 1.5 times higher than that of PBI-based membrane)and durability(300 h at 160°C and 0.2 A cm^(-2))in the fuel cell.The results of this study provide new insights that will guide molecular design from the perspective of microstructure to improve the performance and robustness of HT-PEMs.展开更多
Different drillingfluid systems are designed according to mineral composition,lithology and wellbore stability of different strata.In the present study,the conversion of a non-dispersed polymer drillingfluid into a low ...Different drillingfluid systems are designed according to mineral composition,lithology and wellbore stability of different strata.In the present study,the conversion of a non-dispersed polymer drillingfluid into a low potas-sium anti-collapsing drillingfluid is investigated.Since the two drillingfluids belong to completely different types,the key to this conversion is represented by new inhibitors,dispersants and water-loss agents by which a non-dispersed drillingfluid can be turned into a dispersed drillingfluid while ensuring wellbore stability and reason-able rheology(carrying sand—inhibiting cuttings dispersion).In particular,the(QYZ-1)inhibitors and(FSJSS-2)dispersants are used.The former can inhibit the hydration expansion capacity of clay,reduce the dynamic shear force and weaken the viscosity;the latter can improve the sealing effect and reduce thefiltrate loss.The results have shown that after adding a reasonable proportion of these substances(QYZ-1:FSJSS-2)to the non-dispersed polymer drillingfluid,while the apparent viscosity,plastic viscosity,structural viscosity andfluidity index under-went almost negligible changes,the dynamic plastic ratio increased,and thefiltration loss decreased significantly,thereby indicating good compatibility.According to the tests(conducted in the Leijia area),the density was 1.293 g/cm3,and after standing for 24 h,the SF(static settlement factor)was 0.51.Moreover,thefiltration loss was reduced to 4.0 mL,the rolling recovery rate reached 96.92%,with excellent plugging and anti-collapse performances.展开更多
Metal-organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons,controllable porosities,and well-defined catalytic centers.However,th...Metal-organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons,controllable porosities,and well-defined catalytic centers.However,the poor chemical stability and low electron conductivity limited their activity,and single-functional sites in these frameworks hindered them to show multifunctional roles in catalytic systems.Herein,we have constructed novel metal organic polymers(Co-HAT-CN and Ni-HAT-CN)with dual catalytic centers(metal-N_(4) and metal-N_(2))to catalyze oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).By using different metal centers,the catalytic activity and selectivity were well-tuned.Among them,Co-HAT-CN catalyzed the ORR in a 4e^(-)pathway,with a half-wave potential of 0.8 V versus RHE,while the Ni-HAT-CN catalyze ORR in a 2e^(-)pathway with H_(2)O_(2) selectivity over 90%.Moreover,the Co-HAT-CN delivered an overpotential of 350 mV at 10 mA cm^(-2) with a corresponding Tafel slope of 24 mV dec^(-1) for OER in a 1.0 M KOH aqueous solution.The experimental results revealed that the activities toward ORR were due to the M-N_(4) sites in the frameworks,and both M-N_(4) and M-N_(2) sites contributed to the OER.This work gives us a new platform to construct bifunctional catalysts.展开更多
Synthesis of new carbon nanostructures with tunable properties is vital for precisely regulating electrochemical performance in the wide applications.Herein,we report a novel approach for the oxidative polymerization ...Synthesis of new carbon nanostructures with tunable properties is vital for precisely regulating electrochemical performance in the wide applications.Herein,we report a novel approach for the oxidative polymerization of N-and P-bearing copolymers from the self-assembly of three different monomers(aniline,pyrrole,and phytic acid),and further prepare the respective carbon nanostructures with relatively consistent N dopant(6.2%–8.0%,atom)and varying P concentrations(0.4%–2.8%,atom)via controllable pyrolysis.The impacts of phytic acid addition on the compositional,structural,and morphological evolution of the copolymers and the resulting nanocarbons are well studied through a spectrum of characterizations including N2 sorption,Fourier transform infrared spectroscopy,gel permeation chromatograph,scanning/transmission electron microscopy,and X-ray photoelectron spectroscopy.Gradual fragmentation of the nanosphere structures is evidenced with increasing addition of phytic acid,leading to different nanostructures from hollow nanospheres to 3D aggregates.Nanocarbons decorated with N and P dopants from pyrolysis are further utilized as anode materials in lithium-ion batteries,demonstrating enhanced electrochemical performance,i.e.,a reversible capacity of 380 mAhg^(-1)at 2 Ag^(-1)for NPC-0.5 during 200 cycles.The superior performance originates from the balanced porosity,and appropriate concentrations of P and pyrrolic N,thus pointing the direction for designing high-performance anode materials.展开更多
Based on the theory of crystallization,a solvent-free solid-liquid phase crystallization method called solid-melt crystallization was designed to prepare energetic coordination polymers.Two target compounds[Cu(NPyz)_(...Based on the theory of crystallization,a solvent-free solid-liquid phase crystallization method called solid-melt crystallization was designed to prepare energetic coordination polymers.Two target compounds[Cu(NPyz)_(4)NO_(3)]·NO_(3)(ECPs-1)and Cu(NPyz)_(4)(ClO_(4))_(2)(ECCs-2)were prepared through programmed heating and cooling by using 4-nitropyrazole(NPyz),(Cu(NO_(3))_(2)·5H_(2)O and Cu(ClO_(4))_(2)·5H_(2)O) as raw materials.In addition,crystallization pre-experiments and annealing experiments also verified the feasibility of the method.Their structures were confirmed by IR,elemental analysis,single-crystal X-ray diffraction and powder X-ray diffraction.The physicochemical properties and sensitivity test results showed that ECCs-2 has better thermal stability(T_(d)=221℃),while ECPs-1 is less sensitive to mechanical stimuli(IS=12 J,FS=240 N).Calculations based on EXPLO5 and the Kamlet-Jacobs equation showed that ECCs-2 has more considerable detonation performance(P=25.2 GPa,D=7.5 km/s).In comparison,the more intuitive results from the HN test,flame test,thermal resistance test and lead plate explosion test revealed that ECCs-2 has an“acceptable”detonation performance.The laser detonation test also showed that ECCs-2 is a promising excellent laser detonation material(E=408 mJ,P=24 W,τ=17 ms).展开更多
Lithium-sulfur(Li-S)batteries have attracted increased interest because of the high theoretical energy density,low cost,and environmental friendliness.Conducting polymers(CPs),as one of the most promising materials us...Lithium-sulfur(Li-S)batteries have attracted increased interest because of the high theoretical energy density,low cost,and environmental friendliness.Conducting polymers(CPs),as one of the most promising materials used in Li-S batteries,can not only facilitate electron transfer and buffer the large volumetric change of sulfur benefiting from their porous structure and excellent flexibility,but also enable stronger physical/chemical adsorption capacity toward polysulfides(LiPSs)when doped with abundant heteroatoms to promote the sulfur redox kinetics and achieve the high sulfur loading.This review firstly introduces the properties of various CPs including structural CPs(polypyrrole(PPy),polyaniline(PANi),polyethylene dioxothiophene[PEDOT])and compound CPs(polyethylene oxide(PEO),polyvinyl alcohol(PVA)and poly(acrylic acid)[PAA]),and their application potential in Li-S batteries.Furthermore,the research progress of various CPs in different components(cathode,separator,and interlayer)of Li-S batteries is systematically summarized.Finally,the application perspective of the CPs in Li-S batteries as a potential guidance is comprehensively discussed.展开更多
This paper proposed a high-sensitivity phase imaging eddy current magneto-optical (PI-ECMO) system for carbon fiber reinforced polymer (CFRP) defect detection. In contrast to other eddy current-based detection systems...This paper proposed a high-sensitivity phase imaging eddy current magneto-optical (PI-ECMO) system for carbon fiber reinforced polymer (CFRP) defect detection. In contrast to other eddy current-based detection systems, the proposed system employs a fixed position excitation coil while enabling the detection point to move within the detection region. This configuration effectively mitigates the interference caused by the lift-off effect, which is commonly observed in systems with moving excitation coils. Correspondingly, the relationship between the defect characteristics (orientation and position) and the surface vertical magnetic field distribution (amplitude and phase) is studied in detail by theoretical analysis and numerical simulations. Experiments conducted on woven CFRP plates demonstrate that the designed PI-ECMO system is capable of effectively detecting both surface and internal cracks, as well as impact defects. The excitation current is significantly reduced compared with traditional eddy current magneto-optical (ECMO) systems.展开更多
Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydra...Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydration.An infrared spectral method and a thermogravimetric technique were used to characterize the chemical composition of the HLMP and evaluate its heat stability.Experiments were conducted to measure the linear swelling,rolling recovery rate,and bentonite inhibition rate and evaluate accordingly the inhibition performance of the HLMP.Moreover,the HLMP was characterized through measurements of the zeta potential,particle size distribution,contact angles,and interlayer space testing.As confirmed by the results,the HLMP could successfully be synthesized with a favorable heat stability.Furthermore,favorable results were found for the inhibitory processes of the HLMP on swelling and dispersed hydration during mud shale hydration.The positively charged HLMP could be electrically neutralized with clay particles,thereby inhibiting diffusion in the double electron clay layers.The hydrophobic group in the HLMP molecular structure resulted in the formation of a hydrophobic membrane on the rock surface,enhancing the hydrophobicity of the rock.In addition,the small molecules of the HLMP could plug the spaces between the layers of bentonite crystals,thereby reducing the entry of water molecules and inhibiting shale hydration.展开更多
In this study,lipases of CALB(Candida antarctica lipase B),TLL(Thermomyces lanuginosa lipase),RML(Rhizomucor miehei lipase),CALA(Candida antarctica lipase A)and LU(Lecitase?Ultra)were encapsulated into the nucleotideh...In this study,lipases of CALB(Candida antarctica lipase B),TLL(Thermomyces lanuginosa lipase),RML(Rhizomucor miehei lipase),CALA(Candida antarctica lipase A)and LU(Lecitase?Ultra)were encapsulated into the nucleotidehybrid metal coordination polymers(CPs)for diacylglyerols(DAG)preparation.Guanosine 5'-monophosphate(GMP)and adenosine 5'-monophosphate(AMP)were used as coordinating molecules,and metal ions of Fe^(3+),Ba^(2+),Mn^(2+),Ni^(2+)and Cr^(3+)were applied to prepare matrix.Results indicated that,besides Ba^(2+)with AMP,all other metal ions can coordinate with AMP and GMP to generate CPs.In addition,the AMP/Ni was amorphous when standing temperature was 4℃,while it was crystalline when standing temperature was from 30 to 180℃.DAG content from 47.55%to 64.99%was obtained from glycerolysis by CALB@GMP/Ba,RML@GMP/Ba,TLL@GMP/Ba,RML@GMP/Mn and TLL@GMP/Mn.Additionally,CALB@GMP/Fe showed selectivity towards DAG formation in the esterification and DAG content up to 61.88%was obtained.展开更多
Light transmission spectra of THF solutions of poly (C-60-co-methyl methacrylate)s and poly(C-60-co-styrene)s continuously red-shift with increasing concentration. Formation of fullerene nanoclusters may be responsibl...Light transmission spectra of THF solutions of poly (C-60-co-methyl methacrylate)s and poly(C-60-co-styrene)s continuously red-shift with increasing concentration. Formation of fullerene nanoclusters may be responsible for the unusual spectral shift, with concentration. It has long been scientists' dream to ''tune'' material's properties by simple means, and the C-60-containing polymers represent such a group of novel materials whose optical properties are predictably and reversibly tunable by a simple change in concentration.展开更多
Multiphase copolymers of styrene (S) and ethylene oxide (EO) are amphiphilic, because of the hydrophobic and amorphous polystyrene (PS) segments and the hydrophilic and crystalline polyoxyethylene (PEO). They have man...Multiphase copolymers of styrene (S) and ethylene oxide (EO) are amphiphilic, because of the hydrophobic and amorphous polystyrene (PS) segments and the hydrophilic and crystalline polyoxyethylene (PEO). They have many uses including polymeric surfactants, electrostatic charge reducers, compatibilizer in polymer展开更多
Sulfur-rich copolymers made through inverse vulcanization exhibit a wide range of potentially valuable applications, for example as adsorbents to capture mercury pollution. Among the diverse second monomers of the cop...Sulfur-rich copolymers made through inverse vulcanization exhibit a wide range of potentially valuable applications, for example as adsorbents to capture mercury pollution. Among the diverse second monomers of the copolymers, vegetable oil is a renewable resource, and recycled cooking oils have an important role in saving natural products. However, they need relatively high temperatures(160–180 ℃) to react with sulfur. To develop a low-temperature(130 ℃) reaction process for non-conjugated vegetable oil, we incorporate a small amount of tung oil, which contains conjugated trienes that can produce highly active free radicals during reactions. A variety of analytical techniques(proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and dynamic mechanical analysis) are used to characterize the chemical structures and physical properties of the copolymers. The addition of tung oil is found to significantly improve the thermal stability and mechanical properties of the copolymers. We also investigate the effect of different ratios of raw materials on the gel time, free sulfur content, glass transition temperature T_(g), and degradation temperature of the copolymers. We find that increasing the amount of tung oil in the raw material mixture decreases the gel time and free sulfur content, but increases T_(g) and the degradation temperature. The copolymers exhibit a high adsorption capacity for mercury ions up to 33 mg Hg^(2+) per gram of adsorbent. These results demonstrate the feasibility of using sulfur-rich copolymers as effective mercury removal adsorbents, with the potential for further improvement by foaming the copolymers into porous materials.展开更多
The well-known frictional effect related to liquid-liquid two-phaseflow in pipelines can be reduced using drag-reducing additives.In this study,such an effect has been investigated experimentally using a mixture of oil...The well-known frictional effect related to liquid-liquid two-phaseflow in pipelines can be reduced using drag-reducing additives.In this study,such an effect has been investigated experimentally using a mixture of oil and water.Moreover,numerical simulations have been carried out using the COMSOL simulation software.The mea-surements were taken in a horizontal pipe with the length and diameter equal to 3 and 0.125 m,respectively.Moreover,Polyethylene oxide with 150 ppm was exploited to reduce the drag effect while considering different water-to-oil fractions(0.3,0.4,0.5,and 0.7)and a constant totalflow velocity of 2.3 m/s.As made evident by the results,a significant reduction can be obtained in terms of pressure drop,which becomes even more significant as the water to oil fraction is increased.The maximum achieved drag reduction is 70%with a water fraction of 0.7.The results also show that the addition of polymer additives can also have an impact on theflow pattern.Com-parison of experimental and numerically determined pressure drop indicates that the error is smaller than 7%.展开更多
This study presents a semi-analytical solution to describe the behavior of shape memory polymers(SMPs) based on the nonlinear thermo-visco-hyperelasticity which originates from the concepts of internal state variables...This study presents a semi-analytical solution to describe the behavior of shape memory polymers(SMPs) based on the nonlinear thermo-visco-hyperelasticity which originates from the concepts of internal state variables and rational thermodynamics.This method is developed for the finite bending of multilayers in a dual-shape memory effect(SME) cycle.The layer number and layering order are investigated for two different SMPs and a hyperelastic material.In addition to the semi-analytical solution,the finite element simulation is performed to verify the predicted results,where the outcomes demonstrate the excellent accuracy of the proposed solution for predicting the behavior of the multilayer SMPs.Since this method has a much lower computational cost than the finite element method(FEM),it can be used as an effective tool to analyze the SMP behavior under different conditions,including different materials,different geometries,different layer numbers,and different layer arrangements.展开更多
Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of i...Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of implants for controlled drug delivery. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems because of optimized drug loading and releasing property. Polymeric nano particulate systems are available in wide variety and have established chemistry. Non toxic, biodegradable and biocompatible polymers are available. Some nano particulate polymeric systems possess ability to cross blood brain barrier. They offer protection against chemical degradation. Smart polymers are responsive to atmospheric stimulus like change in temperature;pressure, pH etc. thus are extremely beneficial for targeted drug delivery. Some polymeric systems conjugated with antibodies/specific biomarkers help in detecting molecular targets specifically in cancers. Surface coating with thiolated PEG, Silica-PEG improves water solubility and photo stability. Surface modification of drug carriers e.g. attachment with PEG or dextran to the lipid bilayer increases their blood circulation time. Polymer drug conjugates such as Zoladex, Lupron Depot, On Caspar PEG intron are used in treatment of prostate cancer and lymphoblastic leukemia. Polymeric Drug Delivery systems are being utilized for controlled drug delivery assuring patient compliance.展开更多
Liquid crystalline polymers containing 1,2,3-triazole units as linking groups have been synthesized from the monomers containing triad ester diazide and flexible dialkyne ester by 1,3-cycloaddition reaction and were c...Liquid crystalline polymers containing 1,2,3-triazole units as linking groups have been synthesized from the monomers containing triad ester diazide and flexible dialkyne ester by 1,3-cycloaddition reaction and were characterized. Click reaction of azide and alkyne functionals catalyzed by Cu(I) yielded target polyesters with 1,2,3-triazole groups.The structure of the polymer was confirmed by spectral techniques.GPC analysis reveals that the polymers have moderate molecular weight with narrow distribution.H...展开更多
文摘With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complications.Currently,reagents based on modified natural polymers(which are naturally occurring compounds)and synthetic polymers(SPs)which are polymeric compounds created industrially,are widely used to prevent emerging complications in the drilling process.However,compared to modified natural polymers,SPs form a family of high-molecular-weight compounds that are fully synthesized by undergoing chemical polymerization reactions.SPs provide substantial flexibility in their design.Moreover,their size and chemical composition can be adjusted to provide properties for nearly all the functional objectives of drilling fluids.They can be classified based on chemical ingredients,type of reaction,and their responses to heating.However,some of SPs,due to their structural characteristics,have a high cost,a poor temperature and salt resistance in drilling fluids,and degradation begins when the temperature reaches 130℃.These drawbacks prevent SP use in some medium and deep wells.Thus,this review addresses the historical development,the characteristics,manufacturing methods,classification,and the applications of SPs in drilling fluids.The contributions of SPs as additives to drilling fluids to enhance rheology,filtrate generation,carrying of cuttings,fluid lubricity,and clay/shale stability are explained in detail.The mechanisms,impacts,and advances achieved when SPs are added to drilling fluids are also described.The typical challenges encountered by SPs when deployed in drilling fluids and their advantages and drawbacks are also discussed.Economic issues also impact the applications of SPs in drilling fluids.Consequently,the cost of the most relevant SPs,and the monomers used in their synthesis,are assessed.Environmental impacts of SPs when deployed in drilling fluids,and their manufacturing processes are identified,together with advances in SP-treatment methods aimed at reducing those impacts.Recommendations for required future research addressing SP property and performance gaps are provided.
基金the Fundamental Research Funds for the Central Universities(Grant No.30920041102)National Natural Science Foundation of China(Grant No.11802134).
文摘The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.
基金supported by The National Key Research and Development Program of China(2021YFB4001204)National Natural Science Foundation of China(22379143)。
文摘Acid loss and plasticization of phosphoric acid(PA)-doped high-temperature polymer electrolyte membranes(HT-PEMs)are critical limitations to their practical application in fuel cells.To overcome these barriers,poly(terphenyl piperidinium)s constructed from the m-and p-isomers of terphenyl were synthesized to regulate the microstructure of the membrane.Highly rigid p-terphenyl units prompt the formation of moderate PA aggregates,where the ion-pair interaction between piperidinium and biphosphate is reinforced,leading to a reduction in the plasticizing effect.As a result,there are trade-offs between the proton conductivity,mechanical strength,and PA retention of the membranes with varied m/p-isomer ratios.The designed PA-doped PTP-20m membrane exhibits superior ionic conductivity,good mechanical strength,and excellent PA retention over a wide range of temperature(80–160°C)as well as satisfactory resistance to harsh accelerated aging tests.As a result,the membrane presents a desirable combination of performance(1.462 W cm^(-2) under the H_(2)/O_(2)condition,which is 1.5 times higher than that of PBI-based membrane)and durability(300 h at 160°C and 0.2 A cm^(-2))in the fuel cell.The results of this study provide new insights that will guide molecular design from the perspective of microstructure to improve the performance and robustness of HT-PEMs.
文摘Different drillingfluid systems are designed according to mineral composition,lithology and wellbore stability of different strata.In the present study,the conversion of a non-dispersed polymer drillingfluid into a low potas-sium anti-collapsing drillingfluid is investigated.Since the two drillingfluids belong to completely different types,the key to this conversion is represented by new inhibitors,dispersants and water-loss agents by which a non-dispersed drillingfluid can be turned into a dispersed drillingfluid while ensuring wellbore stability and reason-able rheology(carrying sand—inhibiting cuttings dispersion).In particular,the(QYZ-1)inhibitors and(FSJSS-2)dispersants are used.The former can inhibit the hydration expansion capacity of clay,reduce the dynamic shear force and weaken the viscosity;the latter can improve the sealing effect and reduce thefiltrate loss.The results have shown that after adding a reasonable proportion of these substances(QYZ-1:FSJSS-2)to the non-dispersed polymer drillingfluid,while the apparent viscosity,plastic viscosity,structural viscosity andfluidity index under-went almost negligible changes,the dynamic plastic ratio increased,and thefiltration loss decreased significantly,thereby indicating good compatibility.According to the tests(conducted in the Leijia area),the density was 1.293 g/cm3,and after standing for 24 h,the SF(static settlement factor)was 0.51.Moreover,thefiltration loss was reduced to 4.0 mL,the rolling recovery rate reached 96.92%,with excellent plugging and anti-collapse performances.
基金support from the Natural Science Foundation of Shanghai (20ZR1464000)G.Zeng acknowledges the support from the National Natural Science Foundation of China (21878322,22075309)the Science and Technology Commission of Shanghai Municipality (19ZR1479200,22ZR1470100)。
文摘Metal-organic frameworks and covalent organic frameworks have been widely employed in electrochemical catalysis owing to their designable skeletons,controllable porosities,and well-defined catalytic centers.However,the poor chemical stability and low electron conductivity limited their activity,and single-functional sites in these frameworks hindered them to show multifunctional roles in catalytic systems.Herein,we have constructed novel metal organic polymers(Co-HAT-CN and Ni-HAT-CN)with dual catalytic centers(metal-N_(4) and metal-N_(2))to catalyze oxygen reduction reaction(ORR)and oxygen evolution reaction(OER).By using different metal centers,the catalytic activity and selectivity were well-tuned.Among them,Co-HAT-CN catalyzed the ORR in a 4e^(-)pathway,with a half-wave potential of 0.8 V versus RHE,while the Ni-HAT-CN catalyze ORR in a 2e^(-)pathway with H_(2)O_(2) selectivity over 90%.Moreover,the Co-HAT-CN delivered an overpotential of 350 mV at 10 mA cm^(-2) with a corresponding Tafel slope of 24 mV dec^(-1) for OER in a 1.0 M KOH aqueous solution.The experimental results revealed that the activities toward ORR were due to the M-N_(4) sites in the frameworks,and both M-N_(4) and M-N_(2) sites contributed to the OER.This work gives us a new platform to construct bifunctional catalysts.
基金support from Zhejiang Normal University(YS304320035,YS304320036)the National Key Research and Development Program of China(2016YFB0100100,2016YFA0200200)+5 种基金the National Natural Science Foundation of China(51872283,22075279,21805273,22005297,22005298)the Liaoning Revitalization Talents Program(XLYC1807153)the Funds for Local Science and Technology Development by the Central Government of Liaoning Province(2021JH6/10500112)Dalian Innovation Support Plan for High Level Talents(2019RT09)Dalian National Laboratory For Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(DNL201912,DNL201915)DICP(DICP ZZBS201708,DICP ZZBS201802,DICP I2020032).
文摘Synthesis of new carbon nanostructures with tunable properties is vital for precisely regulating electrochemical performance in the wide applications.Herein,we report a novel approach for the oxidative polymerization of N-and P-bearing copolymers from the self-assembly of three different monomers(aniline,pyrrole,and phytic acid),and further prepare the respective carbon nanostructures with relatively consistent N dopant(6.2%–8.0%,atom)and varying P concentrations(0.4%–2.8%,atom)via controllable pyrolysis.The impacts of phytic acid addition on the compositional,structural,and morphological evolution of the copolymers and the resulting nanocarbons are well studied through a spectrum of characterizations including N2 sorption,Fourier transform infrared spectroscopy,gel permeation chromatograph,scanning/transmission electron microscopy,and X-ray photoelectron spectroscopy.Gradual fragmentation of the nanosphere structures is evidenced with increasing addition of phytic acid,leading to different nanostructures from hollow nanospheres to 3D aggregates.Nanocarbons decorated with N and P dopants from pyrolysis are further utilized as anode materials in lithium-ion batteries,demonstrating enhanced electrochemical performance,i.e.,a reversible capacity of 380 mAhg^(-1)at 2 Ag^(-1)for NPC-0.5 during 200 cycles.The superior performance originates from the balanced porosity,and appropriate concentrations of P and pyrrolic N,thus pointing the direction for designing high-performance anode materials.
基金the projects of National Natural Science Foundation of China(Grant Nos.22175025 and 21905023)for their generous financial support.
文摘Based on the theory of crystallization,a solvent-free solid-liquid phase crystallization method called solid-melt crystallization was designed to prepare energetic coordination polymers.Two target compounds[Cu(NPyz)_(4)NO_(3)]·NO_(3)(ECPs-1)and Cu(NPyz)_(4)(ClO_(4))_(2)(ECCs-2)were prepared through programmed heating and cooling by using 4-nitropyrazole(NPyz),(Cu(NO_(3))_(2)·5H_(2)O and Cu(ClO_(4))_(2)·5H_(2)O) as raw materials.In addition,crystallization pre-experiments and annealing experiments also verified the feasibility of the method.Their structures were confirmed by IR,elemental analysis,single-crystal X-ray diffraction and powder X-ray diffraction.The physicochemical properties and sensitivity test results showed that ECCs-2 has better thermal stability(T_(d)=221℃),while ECPs-1 is less sensitive to mechanical stimuli(IS=12 J,FS=240 N).Calculations based on EXPLO5 and the Kamlet-Jacobs equation showed that ECCs-2 has more considerable detonation performance(P=25.2 GPa,D=7.5 km/s).In comparison,the more intuitive results from the HN test,flame test,thermal resistance test and lead plate explosion test revealed that ECCs-2 has an“acceptable”detonation performance.The laser detonation test also showed that ECCs-2 is a promising excellent laser detonation material(E=408 mJ,P=24 W,τ=17 ms).
基金supported by the National Natural Science Foundation of China(51978569 and 52172097)Key Research and Development Program of Shaanxi Province(2022GY-301)+4 种基金Basic and Public Projects of Zhejiang Province(LGF21E020001)China Postdoctoral Science Foundation(2020 M683467)Basic Research Operating Expenses of XJTU(xzy022022041)China Scholarship Council foundation(201906285020 and 202206280212)support from Faraday Institution LiSTAR Programme(EP/S003053/1,Grant FIRG014).
文摘Lithium-sulfur(Li-S)batteries have attracted increased interest because of the high theoretical energy density,low cost,and environmental friendliness.Conducting polymers(CPs),as one of the most promising materials used in Li-S batteries,can not only facilitate electron transfer and buffer the large volumetric change of sulfur benefiting from their porous structure and excellent flexibility,but also enable stronger physical/chemical adsorption capacity toward polysulfides(LiPSs)when doped with abundant heteroatoms to promote the sulfur redox kinetics and achieve the high sulfur loading.This review firstly introduces the properties of various CPs including structural CPs(polypyrrole(PPy),polyaniline(PANi),polyethylene dioxothiophene[PEDOT])and compound CPs(polyethylene oxide(PEO),polyvinyl alcohol(PVA)and poly(acrylic acid)[PAA]),and their application potential in Li-S batteries.Furthermore,the research progress of various CPs in different components(cathode,separator,and interlayer)of Li-S batteries is systematically summarized.Finally,the application perspective of the CPs in Li-S batteries as a potential guidance is comprehensively discussed.
基金the National Natural Science Foundation of China under Grants No.U2030205,No.62003075,No.61903065,and No.62003074Sichuan Science and Technology Planning Project under Grant No.2022JDJQ0040.
文摘This paper proposed a high-sensitivity phase imaging eddy current magneto-optical (PI-ECMO) system for carbon fiber reinforced polymer (CFRP) defect detection. In contrast to other eddy current-based detection systems, the proposed system employs a fixed position excitation coil while enabling the detection point to move within the detection region. This configuration effectively mitigates the interference caused by the lift-off effect, which is commonly observed in systems with moving excitation coils. Correspondingly, the relationship between the defect characteristics (orientation and position) and the surface vertical magnetic field distribution (amplitude and phase) is studied in detail by theoretical analysis and numerical simulations. Experiments conducted on woven CFRP plates demonstrate that the designed PI-ECMO system is capable of effectively detecting both surface and internal cracks, as well as impact defects. The excitation current is significantly reduced compared with traditional eddy current magneto-optical (ECMO) systems.
基金The work is supported by the Integration and Testing of Safe and Fast Drilling and Completion Technologies for Complex Ultra-Deep Wells(2020F-46)Major Technology Field Test of Joint-Stock Company(Drilling and Production Engineering).Xuyang received the grant.
文摘Water-based drilling fluids can cause hydration of the wellbore rocks,thereby leading to instability.This study aimed to synthesize a hydrophobic small-molecule polymer(HLMP)as an inhibitor to suppress mud shale hydration.An infrared spectral method and a thermogravimetric technique were used to characterize the chemical composition of the HLMP and evaluate its heat stability.Experiments were conducted to measure the linear swelling,rolling recovery rate,and bentonite inhibition rate and evaluate accordingly the inhibition performance of the HLMP.Moreover,the HLMP was characterized through measurements of the zeta potential,particle size distribution,contact angles,and interlayer space testing.As confirmed by the results,the HLMP could successfully be synthesized with a favorable heat stability.Furthermore,favorable results were found for the inhibitory processes of the HLMP on swelling and dispersed hydration during mud shale hydration.The positively charged HLMP could be electrically neutralized with clay particles,thereby inhibiting diffusion in the double electron clay layers.The hydrophobic group in the HLMP molecular structure resulted in the formation of a hydrophobic membrane on the rock surface,enhancing the hydrophobicity of the rock.In addition,the small molecules of the HLMP could plug the spaces between the layers of bentonite crystals,thereby reducing the entry of water molecules and inhibiting shale hydration.
基金the National Natural Science Foundation of China(31772000)。
文摘In this study,lipases of CALB(Candida antarctica lipase B),TLL(Thermomyces lanuginosa lipase),RML(Rhizomucor miehei lipase),CALA(Candida antarctica lipase A)and LU(Lecitase?Ultra)were encapsulated into the nucleotidehybrid metal coordination polymers(CPs)for diacylglyerols(DAG)preparation.Guanosine 5'-monophosphate(GMP)and adenosine 5'-monophosphate(AMP)were used as coordinating molecules,and metal ions of Fe^(3+),Ba^(2+),Mn^(2+),Ni^(2+)and Cr^(3+)were applied to prepare matrix.Results indicated that,besides Ba^(2+)with AMP,all other metal ions can coordinate with AMP and GMP to generate CPs.In addition,the AMP/Ni was amorphous when standing temperature was 4℃,while it was crystalline when standing temperature was from 30 to 180℃.DAG content from 47.55%to 64.99%was obtained from glycerolysis by CALB@GMP/Ba,RML@GMP/Ba,TLL@GMP/Ba,RML@GMP/Mn and TLL@GMP/Mn.Additionally,CALB@GMP/Fe showed selectivity towards DAG formation in the esterification and DAG content up to 61.88%was obtained.
基金This work was in part supported by a grant from the Hong Kong Government Research Grants Council(DAG96/97.SC11)
文摘Light transmission spectra of THF solutions of poly (C-60-co-methyl methacrylate)s and poly(C-60-co-styrene)s continuously red-shift with increasing concentration. Formation of fullerene nanoclusters may be responsible for the unusual spectral shift, with concentration. It has long been scientists' dream to ''tune'' material's properties by simple means, and the C-60-containing polymers represent such a group of novel materials whose optical properties are predictably and reversibly tunable by a simple change in concentration.
文摘Multiphase copolymers of styrene (S) and ethylene oxide (EO) are amphiphilic, because of the hydrophobic and amorphous polystyrene (PS) segments and the hydrophilic and crystalline polyoxyethylene (PEO). They have many uses including polymeric surfactants, electrostatic charge reducers, compatibilizer in polymer
文摘Sulfur-rich copolymers made through inverse vulcanization exhibit a wide range of potentially valuable applications, for example as adsorbents to capture mercury pollution. Among the diverse second monomers of the copolymers, vegetable oil is a renewable resource, and recycled cooking oils have an important role in saving natural products. However, they need relatively high temperatures(160–180 ℃) to react with sulfur. To develop a low-temperature(130 ℃) reaction process for non-conjugated vegetable oil, we incorporate a small amount of tung oil, which contains conjugated trienes that can produce highly active free radicals during reactions. A variety of analytical techniques(proton nuclear magnetic resonance and Fourier-transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and dynamic mechanical analysis) are used to characterize the chemical structures and physical properties of the copolymers. The addition of tung oil is found to significantly improve the thermal stability and mechanical properties of the copolymers. We also investigate the effect of different ratios of raw materials on the gel time, free sulfur content, glass transition temperature T_(g), and degradation temperature of the copolymers. We find that increasing the amount of tung oil in the raw material mixture decreases the gel time and free sulfur content, but increases T_(g) and the degradation temperature. The copolymers exhibit a high adsorption capacity for mercury ions up to 33 mg Hg^(2+) per gram of adsorbent. These results demonstrate the feasibility of using sulfur-rich copolymers as effective mercury removal adsorbents, with the potential for further improvement by foaming the copolymers into porous materials.
文摘The well-known frictional effect related to liquid-liquid two-phaseflow in pipelines can be reduced using drag-reducing additives.In this study,such an effect has been investigated experimentally using a mixture of oil and water.Moreover,numerical simulations have been carried out using the COMSOL simulation software.The mea-surements were taken in a horizontal pipe with the length and diameter equal to 3 and 0.125 m,respectively.Moreover,Polyethylene oxide with 150 ppm was exploited to reduce the drag effect while considering different water-to-oil fractions(0.3,0.4,0.5,and 0.7)and a constant totalflow velocity of 2.3 m/s.As made evident by the results,a significant reduction can be obtained in terms of pressure drop,which becomes even more significant as the water to oil fraction is increased.The maximum achieved drag reduction is 70%with a water fraction of 0.7.The results also show that the addition of polymer additives can also have an impact on theflow pattern.Com-parison of experimental and numerically determined pressure drop indicates that the error is smaller than 7%.
基金Project supported by the Iran National Science Foundation (INSF)(No.98027408)。
文摘This study presents a semi-analytical solution to describe the behavior of shape memory polymers(SMPs) based on the nonlinear thermo-visco-hyperelasticity which originates from the concepts of internal state variables and rational thermodynamics.This method is developed for the finite bending of multilayers in a dual-shape memory effect(SME) cycle.The layer number and layering order are investigated for two different SMPs and a hyperelastic material.In addition to the semi-analytical solution,the finite element simulation is performed to verify the predicted results,where the outcomes demonstrate the excellent accuracy of the proposed solution for predicting the behavior of the multilayer SMPs.Since this method has a much lower computational cost than the finite element method(FEM),it can be used as an effective tool to analyze the SMP behavior under different conditions,including different materials,different geometries,different layer numbers,and different layer arrangements.
文摘Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of implants for controlled drug delivery. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems because of optimized drug loading and releasing property. Polymeric nano particulate systems are available in wide variety and have established chemistry. Non toxic, biodegradable and biocompatible polymers are available. Some nano particulate polymeric systems possess ability to cross blood brain barrier. They offer protection against chemical degradation. Smart polymers are responsive to atmospheric stimulus like change in temperature;pressure, pH etc. thus are extremely beneficial for targeted drug delivery. Some polymeric systems conjugated with antibodies/specific biomarkers help in detecting molecular targets specifically in cancers. Surface coating with thiolated PEG, Silica-PEG improves water solubility and photo stability. Surface modification of drug carriers e.g. attachment with PEG or dextran to the lipid bilayer increases their blood circulation time. Polymer drug conjugates such as Zoladex, Lupron Depot, On Caspar PEG intron are used in treatment of prostate cancer and lymphoblastic leukemia. Polymeric Drug Delivery systems are being utilized for controlled drug delivery assuring patient compliance.
文摘Liquid crystalline polymers containing 1,2,3-triazole units as linking groups have been synthesized from the monomers containing triad ester diazide and flexible dialkyne ester by 1,3-cycloaddition reaction and were characterized. Click reaction of azide and alkyne functionals catalyzed by Cu(I) yielded target polyesters with 1,2,3-triazole groups.The structure of the polymer was confirmed by spectral techniques.GPC analysis reveals that the polymers have moderate molecular weight with narrow distribution.H...