The novel polymer metal chelate electrolytes(polychelates)were prepared by incorporation of cobalt sulfate(Co)into poly(acrylic acid)(PAA)host matrix.Quasi-solid state supercapacitor devices were fabricated using poly...The novel polymer metal chelate electrolytes(polychelates)were prepared by incorporation of cobalt sulfate(Co)into poly(acrylic acid)(PAA)host matrix.Quasi-solid state supercapacitor devices were fabricated using polychelates,PAA-Co X(X:3,5,7,and 10)where X represents the doping fraction(w/w)of Co in PAA.All polymer metal electrolytes were showed excellent bending-stretching properties,thermal stability and electrochemical durability with an optimum ionic conductivity of 3.15×10^(-4) S cm^(-1).Hierarchically porous activated carbon and nano-sized conductive carbon were used to form carbon composite symmetrical device electrodes.The electric double-layer capacitor(EDLC)and redox reactions of Co-incorporated polychelates at the interfaces of porous activated carbon provided an optimum specific capacitance of 341.33 F g^(-1) with a device of PAA-Co7,which is at least 15 times enhancement compared to the device of pristine PAA.The PAA-Co7 device also provided energy density of 21.25 Wh kg^(-1) at a power density of 117.69 W kg^(-1).A prolonged cyclic stability of the device exhibited superior capacitive performance after 10,000 charge-discharge cycles and the maintained 90%of its initial performance.In addition,the supercapacitor with a dimension of 1.5 cm×3 cm containing PAA-Co7 successfully operated the red-blue-green(RGB)LED light.展开更多
The effects of chemical composition and preparation conditions,especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of p...The effects of chemical composition and preparation conditions,especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid were investigated.Among the catalysts studied,Mo_(1.0)V_(0.3)Te_(0.23)Nb_(0.12)O_(x) catalyst calcined in inert atmosphere at 600℃shows the best performance in terms of propane conversion and selectivity to acrylic acid.The results reveal that proper chemical composition, calcination atmosphere and water content affect greatly the catalysts in many ways including structure,chemical composition,which are related to their catalytic performances;and 51.0%propane conversion and 30.5%one-pass yield to acrylic acid can be achieved at the same time.展开更多
Radiation induced grafting of various polymers with different monomers proved to be an attractive means to modify the physical or chemical properties of polymeric materials or textile fabrics. In the present work, rad...Radiation induced grafting of various polymers with different monomers proved to be an attractive means to modify the physical or chemical properties of polymeric materials or textile fabrics. In the present work, radiation induced grafting of viscose rayon fabrics, consisting mainly of cellulose fibers, with acrylic acid monomer has been carried out. The grafting yields have been thoroughly studied as a function of different applied experimental parameters. The impact of the graft yield on the physical properties of the fabrics such as tensile strength, elongation, swelling, moisture absorption, crease recovery angle and also the dyeing properties of the fabrics has been studied. The effect of increasing the contact time of the fabric and monomer solution, at room temperature, after stopping irradiation has been studied in detail as well as the effect of temperature on the irradiated samples also after stopping irradiation. The best grafting yield was obtained on irradiating viscose rayon fabric in methanol-water solvent containing acrylic acid monomer, at a dose 20 kGys, then heating for 7 hours at 80℃ and finally keeping the samples at room temperature for about 20 hours. That treatment significantly increased the final graft yield.展开更多
The absorption process in acrylic acid production was water-intensive.The concentration of acrylic acid before distillation process was low,which induced to large amount of wastewater and enormous energy consumption.I...The absorption process in acrylic acid production was water-intensive.The concentration of acrylic acid before distillation process was low,which induced to large amount of wastewater and enormous energy consumption.In this work,a new method was proposed to concentrate the side stream of absorption column and thus increase the concentration in bottom product by electrodialysis.The influence of operating conditions on concentration rate and specific energy consumption were investigated by a laboratory-scale device.When the voltage drop was 1 V·cP^(-1)(1 cP=10^(-3) Pa·s),flow velocity was 3 cm·s^(-1) and the temperature was 35℃,the concentration rates of acrylic acid and acetic acid could be 203.3%and 156.6%in the continual-ED process.Based on the experimental data,the absorption process combined with ED was simulated,in which the diluted solution from ED process was used as spray water and the concentrated solution was feed back to the absorption column.The results shown that the flow rate of spray water was decreased by 37.1%,and the acrylic acid concentration at the bottom of the tower was increased by 4.56%.The ions exchange membranes before and after use 1200 h were tested by membrane surface morphology(scanning electron microscope),membrane chemical groups(infrared spectra),ion exchange capacity,and membrane area resistance,which indicated the membrane were stable in the acid system.This method provides new method for energy conservation and emission reduction in the traditional chemical industry.展开更多
Comprehensive Summary,As a typical type of sustainable plastic,polyesters can be recycled or upcycled into value-added chemicals in a variety of methods.However,excess reagents are required for most of the depolymeriz...Comprehensive Summary,As a typical type of sustainable plastic,polyesters can be recycled or upcycled into value-added chemicals in a variety of methods.However,excess reagents are required for most of the depolymerization and upcycling processes,causing the emission of environmental pollutants and the waste of chemical resources.Here we demonstrate a one-pot catalytic process to directly crack polylactic acid into acrylic acid by acid catalyst with the assistance of an ionic liquid,Bu4PBr.Polylactic acid is attacked by the Br–from Bu4PBr and the H+from acid to form oligomers containing Br or acryloyl group,and these oligomers serve as intermediates to produce acrylic acid during their mutual transformation.The acrylic acid is vaporized directly from the reactor and obtained in a collector with a selectivity around 90%when polylactic acid is fully converted.This green process shows great advantages in atom economy compared to the conventional recycling/upcycling methods for polyesters,in addition.展开更多
Autonomous self-healing hydrogels were achieved through a dynamic combination of hydrogen bonding and ferric ion(Fe^(3+))migration.N,N′-methylenebis(acrylamide)(MBA),a cross-linking agent,was added in this study.Poly...Autonomous self-healing hydrogels were achieved through a dynamic combination of hydrogen bonding and ferric ion(Fe^(3+))migration.N,N′-methylenebis(acrylamide)(MBA),a cross-linking agent,was added in this study.Poly(acrylic acid)(PAA)/Fe^(3+)and PAA–MBA/Fe^(3+)hydrogels were prepared by introducing Fe^(3+)into the PAA hydrogel network.The ionic bonds were formed between Fe^(3+)ions and carboxyl groups.The microstructure,mechanical properties,and composition of hydrogels were characterized by field emission scanning electron microscopy and Fourier transform infrared spectroscopy.The experimental results showed that PAA/Fe^(3+)and PAA–MBA/Fe^(3+)hydrogels healed themselves without external stimuli.The PAA/Fe^(3+)hydrogel exhibited good mechanical properties,i.e.,the tensile strength of 50 kPa,the breaking elongation of 750%,and the self-healing efficiency of 82%.Meanwhile,the PAA–MBA/Fe^(3+)hydrogel had a tensile strength of 120 kPa.These fabricated hydrogels are biocompatible,which may have promising applications in cartilage tissue engineering.展开更多
Poly(lactic acid)(PLA)is one of the most important bio-plastics,and chemical modification of the already-polymerized poly(lactic acid)chains may enable optimization of its material properties and expand its applicatio...Poly(lactic acid)(PLA)is one of the most important bio-plastics,and chemical modification of the already-polymerized poly(lactic acid)chains may enable optimization of its material properties and expand its application areas.In this study,we demonstrated that poly(lactic acid)can be readily dissolved in acrylic acid at room temperature,and acrylic acid can be graft-polymerized onto poly(lactic acid)chains in solution with the help of photoinitiator benzophenone under 254 nm ultraviolet(UV)irradiation.Similar photo-grafting polymerization of acrylic acid(PAA)has only been studied before in the surface modification of polymer films.The graft ratio could be controlled by various reaction parameters,including irradiation time,benzophenone content,and monomer/polymer ratios.This photo-grafting reaction resulted in high graft ratio(graft ratio PAA/PLA up to 180%)without formation of homopolymers of acrylic acid.When the PAA/PLA graft ratio was higher than 100%,the resulting PLA-g-PAA polymer was found dispersible in water.The pros and cons of the photo-grafting reaction were also discussed.展开更多
Wound healing dressing is increasingly needed in clinical owing to the large quantity of skin damage annually.Excessive reactive oxygen species(ROS)produced through internal or external environmental influences can le...Wound healing dressing is increasingly needed in clinical owing to the large quantity of skin damage annually.Excessive reactive oxygen species(ROS)produced through internal or external environmental influences can lead to lipid peroxidation,protein denaturation,and even DNA damage,and ultimately have harmful effects on cells.Aiming to sufficiently contact with the wound microenvironment and scavenge ROS,superabsorbent poly(acrylic acid)and antioxidant poly(ester amide)(PAA/PEA)hybrid hydrogel has been developed to enhance wound healing.The physical and chemical properties of hybrid hydrogels were studied by Fourier-transform infrared(FTIR)absorption spectrum,compression,swelling,degradation,etc.Besides,the antioxidant properties of hybrid hydrogels can be investigated through the free radical scavenging experiment,and corresponding antioxidant indicators have been tested at the cellular level.Hybrid hydrogel scaffolds supported the proliferation of human umbilical vein endothelial cells and fibroblasts,as well as accelerated angiogenesis and skin regeneration in wounds.The healing properties of wounds in vivo were further assessed on mouse skin wounds.Results showed that PAA/PEA hybrid hydrogel scaffolds significantly accelerated the wound healing process through enhancing granulation formation and re-epithelialization.In summary,these superabsorbent and antioxidative hybrid hydrogels could be served as an excellent wound dressing for full-thickness wound healing.展开更多
1 Results Rosin is a sort of important renewable resources,which is a foremost product of our country forestry. It has very important meaning to modify the rosin based on its molecule structure and active group, to de...1 Results Rosin is a sort of important renewable resources,which is a foremost product of our country forestry. It has very important meaning to modify the rosin based on its molecule structure and active group, to develop some deep processing products, and to endure with rosin new characteristic[1]. This work uses the rosin and acrylic acid to form rosin adduct, and then reacted with 2-hydroxyethyl methacrylate (HEMA) to form ester under the different condition. The effect of different ratios with the ...展开更多
Uranium in the environment can damage human health and ecosystem.There is a need for excellent adsorbents to remove U(Ⅵ)from aqueous solutions.Here we synthesized a novelβ-cyclodextrin/poly(acrylic acid)/permutite(C...Uranium in the environment can damage human health and ecosystem.There is a need for excellent adsorbents to remove U(Ⅵ)from aqueous solutions.Here we synthesized a novelβ-cyclodextrin/poly(acrylic acid)/permutite(CAP)hydrogel composite by a simple method.Physicochemical characterizations of the materials were conducted by XRD,FTIR,SEM,EDX,and TGA.The effect of pH value,contact time,initial U(Ⅵ)concentration,and temperature were researched.A pseudo-second-order kinetic model,intra-particle diffusion model,and Langmuir isotherm model were used to describe the U(Ⅵ)adsorption behavior,and the maximum adsorption capacity of U(Ⅵ)was 833.33 mg/g at 25℃.Thermodynamic analysis showed that the adsorption process of U(Ⅵ)was endothermic and spontaneous.Furthermore,the excellent reusability indicated that CAP hydrogel composite could be potentially used as a promising sorbent for the removal of U(Ⅵ)in wastewater.展开更多
In this paper,poly(vinyl alcohol)-poly(acrylic acid)based transparent semi-interpenetrating network(semi-IPN)hydrogels were synthesized by using a solvent mixture of dimethyl sulfoxide and deionized water via free rad...In this paper,poly(vinyl alcohol)-poly(acrylic acid)based transparent semi-interpenetrating network(semi-IPN)hydrogels were synthesized by using a solvent mixture of dimethyl sulfoxide and deionized water via free radical polymerization and subsequent freeze-thaw technique.The formation of the semi-IPN hydrogels was conformed from FT-IR spectra.The acrylic acid concentration effect on the hydrogels was investigated in terms of transparency,crystalline structure and thermal stability by using UV-visible spectroscopy,X-ray diffraction and thermogravimetric analysis.Swelling behaviours of the semi-IPNPAP hydrogels were studied in deionized water and different pH solutions.The compression and electroactive behaviour was tested in fully hydrated stage by using compression test and by applying electrical voltage.The hydrogels showed displacements under the applying voltage and detailed experiment is illustrated.展开更多
Ultrathin films composed of diazoresin(DR)and polyacrylic acid(PAA)were fabricated.The surface morphology of the films in water was measured using an atomic force microscopy(AFM).The self-assembly technique makes the ...Ultrathin films composed of diazoresin(DR)and polyacrylic acid(PAA)were fabricated.The surface morphology of the films in water was measured using an atomic force microscopy(AFM).The self-assembly technique makes the surface rather flat and uniform.The friction force and its dependence on the velocity differ from the surface charge of the thin films.The friction force of repulsive DR/PAA film increases linearly with velocity and has lower values than that of attractive DR film over the full range of velocity.As the velocity increases,the attractive friction of DR film first decreases to a minimum at a velocity of 2 line/s and then increases all the way.When the surface is repulsive to the friction substrate,the friction of thin films that is determined by hydrated lubrication of polymer chains that is ultralubricated;when it is adhesive to the friction substrate,the friction is mainly contributed from the elastic deformation of adsorbed polymer chains in the low velocity region and from viscous sliding in the presence of hydrated-layer lubrication of the polymer chains in the higher velocity region.展开更多
Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the im...Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the improvement of CNC colloidal stability by surface chemical grafting with polyacrylic acid(PAA)was investigated,and the zeta potential and the charge density of the chemically modified CNC were analyzed.The results showed that an acrylic dosage of 1%(based on the dry weight of CNC)was sufficient to significantly enhance the colloidal stability.CNC,after chemical grafting with PAA,showed better stability against the increase in storage time or solid content of the aqueous medium,compared with the un-modified CNC.展开更多
Photocurable systems are more effective,faster and require less energy than conventional thermal curing methods.To facilitate the ongoing transition toward a biobased economy,photoactive compounds were synthesized fro...Photocurable systems are more effective,faster and require less energy than conventional thermal curing methods.To facilitate the ongoing transition toward a biobased economy,photoactive compounds were synthesized from tall oil fatty acids(TOFA)which is a by-product from wood pulping.In this study,photoactive monomers were synthesized by two different chemical pathways using oleic acid and TOFA as raw materials.Firstly,double bonds present in TOFA were epoxidized,followed by epoxy ring-opening with acrylic acid which introduced photoactive functional groups into the fatty acid backbone.Intermediates and final products were analysed using titration methods(acidic value,epoxy value,iodine value)and FTIR.The preferred final product(3-acryloyloxy-2-hydroxypropyl)-9-hydroxy-10-acryoyloxystearate(Acr-St)was synthesized by both pathways.In the case of oleic acid,a compound of Acr-St was yielded,while in case of TOFA,the Acr-St was present in mixture along with TOFA acryloyloxy derivates(TOFA-acr.der.).The final products were photopolymerized using UV irradiation(396 nm)and as a photoinitiator 3 wt%solution of TPO(2,4,6–trimethylbenzoyl diphenylphosphine oxide)was used.However,only the synthesis using oleic acid yielded a photocurable compound.展开更多
In this paper, we present the development of flexible zinc–air battery. Multiwalled carbon nanotubes(MWCNTs) were added into electrodes to improve their performance. It was found that MWCNTs were effective conductive...In this paper, we present the development of flexible zinc–air battery. Multiwalled carbon nanotubes(MWCNTs) were added into electrodes to improve their performance. It was found that MWCNTs were effective conductive additive in anode as they bridged the zinc particles. Poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS) was applied as a co-binder to enhance both the conductivity and flexibility. A poly(acrylic acid)(PAA) and polyvinyl alcohol(PVA) coated paper separator was used to enhance the battery performance where the PVP–PAA layer facilitated electrolyte storage. The batteries remained functional under bending conditions and after bending. Multiple design optimizations were also carried out for storage and performance purposes.展开更多
With the use of acrylic acid(AA)as a monomer,humic acid(HA)and starch as raw materials,potassium persulfate(KPS)as initiator,and N,Ndimethylacrylamide(MBA)as a cross-linking agent,AA/HA/Starch graft copolymer was prep...With the use of acrylic acid(AA)as a monomer,humic acid(HA)and starch as raw materials,potassium persulfate(KPS)as initiator,and N,Ndimethylacrylamide(MBA)as a cross-linking agent,AA/HA/Starch graft copolymer was prepared and characterized by SEM and FT-IR.The effects of temperature,adsorption time,adsorbent dosage,pH value and Cu^(2+)initial concentration of the solution on the adsorption performance of the crosslinked graft copolymer were also investigated.The results showed that the Cu^(2+)adsorption capacity of the AA/HA/Starch graft copolymer increased firstly and then decreased with increasing adsorbent dosage and the initial pH value of Cu^(2+)solution.With the increase of Cu^(2+)initial concentration and the extension of adsorption time,the adsorption amount of Cu^(2+)increased rapidly and then stabilized.And it decreased slightly with the increase of temperature.At pH value of 5.5,temperature of 298 K,adsorbent dosage of 50 mg,adsorption time of 125 min,and 100 mL Cu^(2+)solution with Cu^(2+)initial concentration of 100 mg/L,the Cu^(2+)adsorption capacity of the crosslinked graft copolymer was 238 mg/g.The adsorption of Cu^(2+)by the adsorbent followed the pseudo-second-order kinetic equation and Langmuir isothermal adsorption model,and the adsorption was attached to monolayer chemical adsorption.This study proved that AA/HA/Starch graft copolymer could be used as an efficient adsorbent for the removal of harmful and toxic metal cations such as Cu^(2+)from industrial wastewater.展开更多
Based on conventional metal-oxide-semiconductor field-effect transistor (MOSFET),a novel kind of chemical field-effect transistor (ChemFET) gas sensor array has been designed and fabricated.The obtained sensor consist...Based on conventional metal-oxide-semiconductor field-effect transistor (MOSFET),a novel kind of chemical field-effect transistor (ChemFET) gas sensor array has been designed and fabricated.The obtained sensor consists of self-assembly polyaniline (PAN) composite film containing poly(acrylic acid) (PAA) which was used as gate material of MOSFET instead of conventional metallic gate.The UV-Vis absorption spectra of PAN/PAA films were characterized.The NO_2 gas sensitive property of the ChemFET sensor array was also investigated.Results show that the drain current of devices increases with increasing of back-side voltage,and decreases with the increase of NO_2 concentration when the NO_2 concentration is below 20μg/g.The temperature dependence of ChemFET sensor array shows that the drain current of ChemFET sensor decreases with increasing of temperature.展开更多
The implantable artificial hair was prepared by grafting collagen on the surface of poly( ethylene terephthalate)( PET) to improve its biocompatibility. Acrylic acid( AAc) was used to modify the surface properties of ...The implantable artificial hair was prepared by grafting collagen on the surface of poly( ethylene terephthalate)( PET) to improve its biocompatibility. Acrylic acid( AAc) was used to modify the surface properties of PET firstly,and then collagen was grafted on the PET-AAc surface. The concentration of collagen solution was discussed to graft more collagen on PET surface. Composites were well characterized by scanning electron microscopy( SEM),Fourier transform infrared spectroscopy( FTIR) and X-ray photoelectron spectroscopy( XPS). SEM indicated that collagen with about 3. 07μm thickness was coated on PET surface when the concentration of collagen solution was 1. 0 mg/m L. FTIR and XPS showed AAc and collagen were both on the surface of PET monofilaments. The optimized concentration of collagen solution was 1. 0 mg/m L,resulting in the most grafting density of 3. 46 μg/cm2. It can be concluded that a large amount of collagen is coated on PET surface.展开更多
Polyaspartic acid(PASP)composite,a scale inhibitor,was prepared from PASP,itaconic acid—acrylic acid—acrylic ester(IA-AA-AE)terpolymer and 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA).The scale inhibition of PA...Polyaspartic acid(PASP)composite,a scale inhibitor,was prepared from PASP,itaconic acid—acrylic acid—acrylic ester(IA-AA-AE)terpolymer and 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA).The scale inhibition of PASP composite and the effect of its synergism with a magnetic field on scale inhibition were investigated.Calcium carbonate crystals in scale samples were characterized by means of SEM and XRD.The static and dynamic experiments show that the chelating function of PASP composite for Ca2+can be enhanced by synergism with a magnetic field.Under Ca2+650 mg/L,HCO3-1,300 mg/L and PASPcomposite 4 mg/L,the scale inhibition rate of PASP composite in magnetic water can increase by 10%in static state and by 20%in dynamic experiments.Scanning electron microscope(SEM)and X-ray diffraction(XRD)results show that calcite and aragonite can be completely transformed into vaterite by using PASP composite.展开更多
基金Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia for funding this research work。
文摘The novel polymer metal chelate electrolytes(polychelates)were prepared by incorporation of cobalt sulfate(Co)into poly(acrylic acid)(PAA)host matrix.Quasi-solid state supercapacitor devices were fabricated using polychelates,PAA-Co X(X:3,5,7,and 10)where X represents the doping fraction(w/w)of Co in PAA.All polymer metal electrolytes were showed excellent bending-stretching properties,thermal stability and electrochemical durability with an optimum ionic conductivity of 3.15×10^(-4) S cm^(-1).Hierarchically porous activated carbon and nano-sized conductive carbon were used to form carbon composite symmetrical device electrodes.The electric double-layer capacitor(EDLC)and redox reactions of Co-incorporated polychelates at the interfaces of porous activated carbon provided an optimum specific capacitance of 341.33 F g^(-1) with a device of PAA-Co7,which is at least 15 times enhancement compared to the device of pristine PAA.The PAA-Co7 device also provided energy density of 21.25 Wh kg^(-1) at a power density of 117.69 W kg^(-1).A prolonged cyclic stability of the device exhibited superior capacitive performance after 10,000 charge-discharge cycles and the maintained 90%of its initial performance.In addition,the supercapacitor with a dimension of 1.5 cm×3 cm containing PAA-Co7 successfully operated the red-blue-green(RGB)LED light.
文摘The effects of chemical composition and preparation conditions,especially calcination atmosphere and water content on the catalytic performances of MoVTeNbO mixed oxide catalyst system for the selective oxidation of propane to acrylic acid were investigated.Among the catalysts studied,Mo_(1.0)V_(0.3)Te_(0.23)Nb_(0.12)O_(x) catalyst calcined in inert atmosphere at 600℃shows the best performance in terms of propane conversion and selectivity to acrylic acid.The results reveal that proper chemical composition, calcination atmosphere and water content affect greatly the catalysts in many ways including structure,chemical composition,which are related to their catalytic performances;and 51.0%propane conversion and 30.5%one-pass yield to acrylic acid can be achieved at the same time.
文摘Radiation induced grafting of various polymers with different monomers proved to be an attractive means to modify the physical or chemical properties of polymeric materials or textile fabrics. In the present work, radiation induced grafting of viscose rayon fabrics, consisting mainly of cellulose fibers, with acrylic acid monomer has been carried out. The grafting yields have been thoroughly studied as a function of different applied experimental parameters. The impact of the graft yield on the physical properties of the fabrics such as tensile strength, elongation, swelling, moisture absorption, crease recovery angle and also the dyeing properties of the fabrics has been studied. The effect of increasing the contact time of the fabric and monomer solution, at room temperature, after stopping irradiation has been studied in detail as well as the effect of temperature on the irradiated samples also after stopping irradiation. The best grafting yield was obtained on irradiating viscose rayon fabric in methanol-water solvent containing acrylic acid monomer, at a dose 20 kGys, then heating for 7 hours at 80℃ and finally keeping the samples at room temperature for about 20 hours. That treatment significantly increased the final graft yield.
基金supported by the National Key Research and Development Program of China(2016YFC0401202)Key Research and Development Program of Hebei Province(18394008D)。
文摘The absorption process in acrylic acid production was water-intensive.The concentration of acrylic acid before distillation process was low,which induced to large amount of wastewater and enormous energy consumption.In this work,a new method was proposed to concentrate the side stream of absorption column and thus increase the concentration in bottom product by electrodialysis.The influence of operating conditions on concentration rate and specific energy consumption were investigated by a laboratory-scale device.When the voltage drop was 1 V·cP^(-1)(1 cP=10^(-3) Pa·s),flow velocity was 3 cm·s^(-1) and the temperature was 35℃,the concentration rates of acrylic acid and acetic acid could be 203.3%and 156.6%in the continual-ED process.Based on the experimental data,the absorption process combined with ED was simulated,in which the diluted solution from ED process was used as spray water and the concentrated solution was feed back to the absorption column.The results shown that the flow rate of spray water was decreased by 37.1%,and the acrylic acid concentration at the bottom of the tower was increased by 4.56%.The ions exchange membranes before and after use 1200 h were tested by membrane surface morphology(scanning electron microscope),membrane chemical groups(infrared spectra),ion exchange capacity,and membrane area resistance,which indicated the membrane were stable in the acid system.This method provides new method for energy conservation and emission reduction in the traditional chemical industry.
基金financial support from the National Natural Science Foundation of China(22072002,21932002,21821004)China National Petroleum Corporation-Peking University Strategic Cooperation Project of Fundamental Research.D.M.acknowledges support from the Tencent Foundation through the XPLORER.PRIZE.
文摘Comprehensive Summary,As a typical type of sustainable plastic,polyesters can be recycled or upcycled into value-added chemicals in a variety of methods.However,excess reagents are required for most of the depolymerization and upcycling processes,causing the emission of environmental pollutants and the waste of chemical resources.Here we demonstrate a one-pot catalytic process to directly crack polylactic acid into acrylic acid by acid catalyst with the assistance of an ionic liquid,Bu4PBr.Polylactic acid is attacked by the Br–from Bu4PBr and the H+from acid to form oligomers containing Br or acryloyl group,and these oligomers serve as intermediates to produce acrylic acid during their mutual transformation.The acrylic acid is vaporized directly from the reactor and obtained in a collector with a selectivity around 90%when polylactic acid is fully converted.This green process shows great advantages in atom economy compared to the conventional recycling/upcycling methods for polyesters,in addition.
基金supported by the General Project of Natural Science of Shanxi Provincial Basic Research Program(Grant No.202203021211125)the National Natural Science Foundation of China(Grant No.11802197).
文摘Autonomous self-healing hydrogels were achieved through a dynamic combination of hydrogen bonding and ferric ion(Fe^(3+))migration.N,N′-methylenebis(acrylamide)(MBA),a cross-linking agent,was added in this study.Poly(acrylic acid)(PAA)/Fe^(3+)and PAA–MBA/Fe^(3+)hydrogels were prepared by introducing Fe^(3+)into the PAA hydrogel network.The ionic bonds were formed between Fe^(3+)ions and carboxyl groups.The microstructure,mechanical properties,and composition of hydrogels were characterized by field emission scanning electron microscopy and Fourier transform infrared spectroscopy.The experimental results showed that PAA/Fe^(3+)and PAA–MBA/Fe^(3+)hydrogels healed themselves without external stimuli.The PAA/Fe^(3+)hydrogel exhibited good mechanical properties,i.e.,the tensile strength of 50 kPa,the breaking elongation of 750%,and the self-healing efficiency of 82%.Meanwhile,the PAA–MBA/Fe^(3+)hydrogel had a tensile strength of 120 kPa.These fabricated hydrogels are biocompatible,which may have promising applications in cartilage tissue engineering.
基金financially supported by the National Natural Science Foundation of China (No. 21434008)
文摘Poly(lactic acid)(PLA)is one of the most important bio-plastics,and chemical modification of the already-polymerized poly(lactic acid)chains may enable optimization of its material properties and expand its application areas.In this study,we demonstrated that poly(lactic acid)can be readily dissolved in acrylic acid at room temperature,and acrylic acid can be graft-polymerized onto poly(lactic acid)chains in solution with the help of photoinitiator benzophenone under 254 nm ultraviolet(UV)irradiation.Similar photo-grafting polymerization of acrylic acid(PAA)has only been studied before in the surface modification of polymer films.The graft ratio could be controlled by various reaction parameters,including irradiation time,benzophenone content,and monomer/polymer ratios.This photo-grafting reaction resulted in high graft ratio(graft ratio PAA/PLA up to 180%)without formation of homopolymers of acrylic acid.When the PAA/PLA graft ratio was higher than 100%,the resulting PLA-g-PAA polymer was found dispersible in water.The pros and cons of the photo-grafting reaction were also discussed.
基金This work sincerely acknowledges the support from the Science and Technology Planning Project of Shenzhen(JCYJ20190813153409172)Chunhui Project from Education Ministry of China(Z2016125)+1 种基金Sichuan Science and Technology Program(2019YFG0251,2019JDTD0024)Young scholars for reserve talents of Xihua University.
文摘Wound healing dressing is increasingly needed in clinical owing to the large quantity of skin damage annually.Excessive reactive oxygen species(ROS)produced through internal or external environmental influences can lead to lipid peroxidation,protein denaturation,and even DNA damage,and ultimately have harmful effects on cells.Aiming to sufficiently contact with the wound microenvironment and scavenge ROS,superabsorbent poly(acrylic acid)and antioxidant poly(ester amide)(PAA/PEA)hybrid hydrogel has been developed to enhance wound healing.The physical and chemical properties of hybrid hydrogels were studied by Fourier-transform infrared(FTIR)absorption spectrum,compression,swelling,degradation,etc.Besides,the antioxidant properties of hybrid hydrogels can be investigated through the free radical scavenging experiment,and corresponding antioxidant indicators have been tested at the cellular level.Hybrid hydrogel scaffolds supported the proliferation of human umbilical vein endothelial cells and fibroblasts,as well as accelerated angiogenesis and skin regeneration in wounds.The healing properties of wounds in vivo were further assessed on mouse skin wounds.Results showed that PAA/PEA hybrid hydrogel scaffolds significantly accelerated the wound healing process through enhancing granulation formation and re-epithelialization.In summary,these superabsorbent and antioxidative hybrid hydrogels could be served as an excellent wound dressing for full-thickness wound healing.
文摘1 Results Rosin is a sort of important renewable resources,which is a foremost product of our country forestry. It has very important meaning to modify the rosin based on its molecule structure and active group, to develop some deep processing products, and to endure with rosin new characteristic[1]. This work uses the rosin and acrylic acid to form rosin adduct, and then reacted with 2-hydroxyethyl methacrylate (HEMA) to form ester under the different condition. The effect of different ratios with the ...
基金the Scientific Research Initiation Project of Fuzhou University for Thousand Talents Program Experts(0041-510248)the Science and Technology Development Fund of Fuzhou University(0041-510299)。
文摘Uranium in the environment can damage human health and ecosystem.There is a need for excellent adsorbents to remove U(Ⅵ)from aqueous solutions.Here we synthesized a novelβ-cyclodextrin/poly(acrylic acid)/permutite(CAP)hydrogel composite by a simple method.Physicochemical characterizations of the materials were conducted by XRD,FTIR,SEM,EDX,and TGA.The effect of pH value,contact time,initial U(Ⅵ)concentration,and temperature were researched.A pseudo-second-order kinetic model,intra-particle diffusion model,and Langmuir isotherm model were used to describe the U(Ⅵ)adsorption behavior,and the maximum adsorption capacity of U(Ⅵ)was 833.33 mg/g at 25℃.Thermodynamic analysis showed that the adsorption process of U(Ⅵ)was endothermic and spontaneous.Furthermore,the excellent reusability indicated that CAP hydrogel composite could be potentially used as a promising sorbent for the removal of U(Ⅵ)in wastewater.
基金This work was supported by the National Research Foundation of Korea[NRF2015R1A3A2066301]。
文摘In this paper,poly(vinyl alcohol)-poly(acrylic acid)based transparent semi-interpenetrating network(semi-IPN)hydrogels were synthesized by using a solvent mixture of dimethyl sulfoxide and deionized water via free radical polymerization and subsequent freeze-thaw technique.The formation of the semi-IPN hydrogels was conformed from FT-IR spectra.The acrylic acid concentration effect on the hydrogels was investigated in terms of transparency,crystalline structure and thermal stability by using UV-visible spectroscopy,X-ray diffraction and thermogravimetric analysis.Swelling behaviours of the semi-IPNPAP hydrogels were studied in deionized water and different pH solutions.The compression and electroactive behaviour was tested in fully hydrated stage by using compression test and by applying electrical voltage.The hydrogels showed displacements under the applying voltage and detailed experiment is illustrated.
基金Supported by the National Natural Science Foundation of China(51273059)Young Teachers International Communication Program of Hubei Province Education Administration of China(2012-1)Foundation of Hubei Provincial Key Laboratory of Green Materials for Light Industry
文摘Ultrathin films composed of diazoresin(DR)and polyacrylic acid(PAA)were fabricated.The surface morphology of the films in water was measured using an atomic force microscopy(AFM).The self-assembly technique makes the surface rather flat and uniform.The friction force and its dependence on the velocity differ from the surface charge of the thin films.The friction force of repulsive DR/PAA film increases linearly with velocity and has lower values than that of attractive DR film over the full range of velocity.As the velocity increases,the attractive friction of DR film first decreases to a minimum at a velocity of 2 line/s and then increases all the way.When the surface is repulsive to the friction substrate,the friction of thin films that is determined by hydrated lubrication of polymer chains that is ultralubricated;when it is adhesive to the friction substrate,the friction is mainly contributed from the elastic deformation of adsorbed polymer chains in the low velocity region and from viscous sliding in the presence of hydrated-layer lubrication of the polymer chains in the higher velocity region.
基金support from the Tianjin Municipal Science and Technology Commission (Grant No.12ZCZDGX01100).
文摘Cellulose nano-crystals(CNC)can be tailored for various value-added applications.However,its use in aqueous systems is hampered by its limited dispersability,especially at a high CNC concentration.In this study,the improvement of CNC colloidal stability by surface chemical grafting with polyacrylic acid(PAA)was investigated,and the zeta potential and the charge density of the chemically modified CNC were analyzed.The results showed that an acrylic dosage of 1%(based on the dry weight of CNC)was sufficient to significantly enhance the colloidal stability.CNC,after chemical grafting with PAA,showed better stability against the increase in storage time or solid content of the aqueous medium,compared with the un-modified CNC.
文摘Photocurable systems are more effective,faster and require less energy than conventional thermal curing methods.To facilitate the ongoing transition toward a biobased economy,photoactive compounds were synthesized from tall oil fatty acids(TOFA)which is a by-product from wood pulping.In this study,photoactive monomers were synthesized by two different chemical pathways using oleic acid and TOFA as raw materials.Firstly,double bonds present in TOFA were epoxidized,followed by epoxy ring-opening with acrylic acid which introduced photoactive functional groups into the fatty acid backbone.Intermediates and final products were analysed using titration methods(acidic value,epoxy value,iodine value)and FTIR.The preferred final product(3-acryloyloxy-2-hydroxypropyl)-9-hydroxy-10-acryoyloxystearate(Acr-St)was synthesized by both pathways.In the case of oleic acid,a compound of Acr-St was yielded,while in case of TOFA,the Acr-St was present in mixture along with TOFA acryloyloxy derivates(TOFA-acr.der.).The final products were photopolymerized using UV irradiation(396 nm)and as a photoinitiator 3 wt%solution of TPO(2,4,6–trimethylbenzoyl diphenylphosphine oxide)was used.However,only the synthesis using oleic acid yielded a photocurable compound.
文摘In this paper, we present the development of flexible zinc–air battery. Multiwalled carbon nanotubes(MWCNTs) were added into electrodes to improve their performance. It was found that MWCNTs were effective conductive additive in anode as they bridged the zinc particles. Poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS) was applied as a co-binder to enhance both the conductivity and flexibility. A poly(acrylic acid)(PAA) and polyvinyl alcohol(PVA) coated paper separator was used to enhance the battery performance where the PVP–PAA layer facilitated electrolyte storage. The batteries remained functional under bending conditions and after bending. Multiple design optimizations were also carried out for storage and performance purposes.
文摘With the use of acrylic acid(AA)as a monomer,humic acid(HA)and starch as raw materials,potassium persulfate(KPS)as initiator,and N,Ndimethylacrylamide(MBA)as a cross-linking agent,AA/HA/Starch graft copolymer was prepared and characterized by SEM and FT-IR.The effects of temperature,adsorption time,adsorbent dosage,pH value and Cu^(2+)initial concentration of the solution on the adsorption performance of the crosslinked graft copolymer were also investigated.The results showed that the Cu^(2+)adsorption capacity of the AA/HA/Starch graft copolymer increased firstly and then decreased with increasing adsorbent dosage and the initial pH value of Cu^(2+)solution.With the increase of Cu^(2+)initial concentration and the extension of adsorption time,the adsorption amount of Cu^(2+)increased rapidly and then stabilized.And it decreased slightly with the increase of temperature.At pH value of 5.5,temperature of 298 K,adsorbent dosage of 50 mg,adsorption time of 125 min,and 100 mL Cu^(2+)solution with Cu^(2+)initial concentration of 100 mg/L,the Cu^(2+)adsorption capacity of the crosslinked graft copolymer was 238 mg/g.The adsorption of Cu^(2+)by the adsorbent followed the pseudo-second-order kinetic equation and Langmuir isothermal adsorption model,and the adsorption was attached to monolayer chemical adsorption.This study proved that AA/HA/Starch graft copolymer could be used as an efficient adsorbent for the removal of harmful and toxic metal cations such as Cu^(2+)from industrial wastewater.
基金This work is supported by the National Science Foundation of China （Grants No. 60372002, 60425101）
文摘Based on conventional metal-oxide-semiconductor field-effect transistor (MOSFET),a novel kind of chemical field-effect transistor (ChemFET) gas sensor array has been designed and fabricated.The obtained sensor consists of self-assembly polyaniline (PAN) composite film containing poly(acrylic acid) (PAA) which was used as gate material of MOSFET instead of conventional metallic gate.The UV-Vis absorption spectra of PAN/PAA films were characterized.The NO_2 gas sensitive property of the ChemFET sensor array was also investigated.Results show that the drain current of devices increases with increasing of back-side voltage,and decreases with the increase of NO_2 concentration when the NO_2 concentration is below 20μg/g.The temperature dependence of ChemFET sensor array shows that the drain current of ChemFET sensor decreases with increasing of temperature.
基金Beijing Municipal Commission of Science and Technology Plan Projects,China(No.KYTG02170206/016)Open Project of Beijing Key Laboratory of Clothing Materials R&D and Assessment,China(No.KYTG02170205)
文摘The implantable artificial hair was prepared by grafting collagen on the surface of poly( ethylene terephthalate)( PET) to improve its biocompatibility. Acrylic acid( AAc) was used to modify the surface properties of PET firstly,and then collagen was grafted on the PET-AAc surface. The concentration of collagen solution was discussed to graft more collagen on PET surface. Composites were well characterized by scanning electron microscopy( SEM),Fourier transform infrared spectroscopy( FTIR) and X-ray photoelectron spectroscopy( XPS). SEM indicated that collagen with about 3. 07μm thickness was coated on PET surface when the concentration of collagen solution was 1. 0 mg/m L. FTIR and XPS showed AAc and collagen were both on the surface of PET monofilaments. The optimized concentration of collagen solution was 1. 0 mg/m L,resulting in the most grafting density of 3. 46 μg/cm2. It can be concluded that a large amount of collagen is coated on PET surface.
基金supported by the Natural Science Foundation of Hebei Province of China(B2004000749).
文摘Polyaspartic acid(PASP)composite,a scale inhibitor,was prepared from PASP,itaconic acid—acrylic acid—acrylic ester(IA-AA-AE)terpolymer and 2-phosphonobutane-1,2,4-tricarboxylic acid(PBTCA).The scale inhibition of PASP composite and the effect of its synergism with a magnetic field on scale inhibition were investigated.Calcium carbonate crystals in scale samples were characterized by means of SEM and XRD.The static and dynamic experiments show that the chelating function of PASP composite for Ca2+can be enhanced by synergism with a magnetic field.Under Ca2+650 mg/L,HCO3-1,300 mg/L and PASPcomposite 4 mg/L,the scale inhibition rate of PASP composite in magnetic water can increase by 10%in static state and by 20%in dynamic experiments.Scanning electron microscope(SEM)and X-ray diffraction(XRD)results show that calcite and aragonite can be completely transformed into vaterite by using PASP composite.
