In this work, a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water. Inorganic anions in slightly soluble organic solvents can be determined by the in-...In this work, a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water. Inorganic anions in slightly soluble organic solvents can be determined by the in-line hollow fiber membrane extractor coupled with ion chromatography at first time. Different aspects of the extraction procedure such as magnetic stirring speed, extraction flow rate and extraction time were optimized to achieve high extraction efficiency and good separation results. Satisfactory linear range, limits of detection and good repeatability were obtained. The procedure was applied to analyze inorganic anions in two commercial ethyl acetate samples.展开更多
Catalytic treatments of VOCs at normal temperature can greatly reduce the cost and temperature of processing,and improve the safety factor in line with the requirements of green chemistry.Activated carbon fiber(ACF)wa...Catalytic treatments of VOCs at normal temperature can greatly reduce the cost and temperature of processing,and improve the safety factor in line with the requirements of green chemistry.Activated carbon fiber(ACF)was pretreated with 10%H_(2)SO_(4)by single factor optimization to increase specific surface area and pore volume obviously.The catalytic ozonation performance of ACF loaded with Au,Ag,Pt and Pd noble metals on ethyl acetate was investigated and Pd/ACF was selected as the optimal catalyst which had certain stability.Pd is uniformly distributed on the surface of ACF,and Palladium mainly exists in the form of Pd0 with a amount of Pd+2.The specific surface area of the catalysts gradually decreases as the loading increases.The activation energy of ethyl acetate calculated by Arrhenius equation is 113 kJ mol 1.With 1%Pd loading and the concentration ratio of ozone to ethyl acetate is 3:1,catalytic ozonation performance is maximized and the conversion rate of ethyl acetate reached to 60%in 3050℃Cat 15,00030,000 h^1.展开更多
Acetalizatioin on the blend fibers of poly(vinyl alcohol) (PVA) and soybean protein (SP) was studied by using dialdehydes as cross-linking agents. The optimal acetalization conditions were determined by Latin square e...Acetalizatioin on the blend fibers of poly(vinyl alcohol) (PVA) and soybean protein (SP) was studied by using dialdehydes as cross-linking agents. The optimal acetalization conditions were determined by Latin square experiment, where the modified fibers with good mechanical properties can be achieved by treating in 41 g/L dialdehyde solution at 67 ℃ for 9 min. The cross-linking reactions of PVA and SP with dialdehydes were confirmed by Fourier transform infrared (FTIR) spectroscopy. Tensile test and boiling water shrinkage measurements showed that the physical properties of PVA/SP fibers crosslinked by dialdehydes were improved comparing with those formalized fibers.展开更多
The effects of Ethylene-Vinyl Acetate copolymer （EVA） latex as an additive or a glass fiber surface modifier on the properties of Glass-Fiber （ GF ）/ Magnesium Oxychloride Cement （MOC） composites was studied. Th...The effects of Ethylene-Vinyl Acetate copolymer （EVA） latex as an additive or a glass fiber surface modifier on the properties of Glass-Fiber （ GF ）/ Magnesium Oxychloride Cement （MOC） composites was studied. The mechanical properties, water resistance aud aging resistance of the cured GF/ MOC composites were estimated and chemical ingredients analysis and morphological study of the GF/ MOC composites were also performed. It is found that EVA added to the MOC matrix could substantially improve the interfacial adhesion, water resistance aud aging resistance of GF/ MOC composites. EVA treatment on glass fibers resulted in decreasing initial flexural strength of GF/ MOC composites while enhancing the soft coefficients. In addition, the drying time and dilution of the EVA treatment on glass fibers also had an otwioas effect on the properties of GF/ MOC composites. However, excessive EVA interfered with the growth of the 5 Mg（ OH）2· MgCl2 ·8H2O crystal and the properties of GF / MOC composites.展开更多
PLLA/CA mixtures of different compositions were successfully electrospun to obtain composite nanofibrous membranes. The microstructures of the membrances changed from homogeneous to heterogeneous with the addition of ...PLLA/CA mixtures of different compositions were successfully electrospun to obtain composite nanofibrous membranes. The microstructures of the membrances changed from homogeneous to heterogeneous with the addition of CA, which was observed by FE-ESEM. The PLLA/CA fabric membranes were characterized by mechanical testing, DSC and contact angle measurements. The tensile stress of the composite fibrous membranes increased obviously with the increase of CA content. DSC results indicated that the CA component was the main factor for the changes of enthalpies in the composite fibers. Contact angle measurements showed the hydrophilicity of the electrospun nanofiber membranes was improved with the addition of CA.展开更多
Environmental-stimulus-triggered self-folding mechanisms have found promising applications in many engineering fields.Recently,a water-activated self-folding procedure has been designed by using the electrospun polyvi...Environmental-stimulus-triggered self-folding mechanisms have found promising applications in many engineering fields.Recently,a water-activated self-folding procedure has been designed by using the electrospun polyvinyl acetate(PVAc)fiber mat which contains high tensile residual stresses in the vitrified fibers during the spinning processes.The water permeation initiates plasticization of PVAc fiber mat and leads to a material shrinkage.When water diffusion starts at the top surface of a PVAc sheet,a shrinkage variation along the diffusion pathway forms a bending hinge on the sheet,which has been demonstrated in 3D origami design.To capture the water-triggered plasticization mechanism and chemomechanical coupling deformation compatibility,a consistent finite deformation viscoplastic model is developed for the PVAc fiber mat under coupled chemomechanical loading conditions.The residual stress and‘fixed’strain are modeled through the unrecoverable plastic strain in the PVAc fiber mat.As water permeates into the PVAc fiber mat,the induced increase in mixing entropy lowers the glass transition temperature of the material,and results in a gradual relaxation of the fixed viscoplastic strain.A non-Fickian diffusion model suitable for glassy material is adopted to capture the water permeation in the PVAc fiber mat.After calibrated and validated by a series of experiments,the proposed model is implemented in ABAQUS software to simulate the water-activated self-folding of PVAc sheet.The numerical example for a typical origami design suggests a promising engineering application prospect.展开更多
基金supported by National Natural Science Foundation of China(No.20775070)by Zhejiang Provincial Natural Science Foundation of China(No.R4080124)Zhejiang Qianjiang Project of Science and Technology for Competent People(No.2008R10028).
文摘In this work, a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water. Inorganic anions in slightly soluble organic solvents can be determined by the in-line hollow fiber membrane extractor coupled with ion chromatography at first time. Different aspects of the extraction procedure such as magnetic stirring speed, extraction flow rate and extraction time were optimized to achieve high extraction efficiency and good separation results. Satisfactory linear range, limits of detection and good repeatability were obtained. The procedure was applied to analyze inorganic anions in two commercial ethyl acetate samples.
基金the National Key R&D Program of the Ministry of Science and Technology,China(Grant No.2018YFC0705304)and the Key Scientific and Technological Support Projects,Tianjin City,China(Grant No.19YFZCSF01090).
文摘Catalytic treatments of VOCs at normal temperature can greatly reduce the cost and temperature of processing,and improve the safety factor in line with the requirements of green chemistry.Activated carbon fiber(ACF)was pretreated with 10%H_(2)SO_(4)by single factor optimization to increase specific surface area and pore volume obviously.The catalytic ozonation performance of ACF loaded with Au,Ag,Pt and Pd noble metals on ethyl acetate was investigated and Pd/ACF was selected as the optimal catalyst which had certain stability.Pd is uniformly distributed on the surface of ACF,and Palladium mainly exists in the form of Pd0 with a amount of Pd+2.The specific surface area of the catalysts gradually decreases as the loading increases.The activation energy of ethyl acetate calculated by Arrhenius equation is 113 kJ mol 1.With 1%Pd loading and the concentration ratio of ozone to ethyl acetate is 3:1,catalytic ozonation performance is maximized and the conversion rate of ethyl acetate reached to 60%in 3050℃Cat 15,00030,000 h^1.
文摘Acetalizatioin on the blend fibers of poly(vinyl alcohol) (PVA) and soybean protein (SP) was studied by using dialdehydes as cross-linking agents. The optimal acetalization conditions were determined by Latin square experiment, where the modified fibers with good mechanical properties can be achieved by treating in 41 g/L dialdehyde solution at 67 ℃ for 9 min. The cross-linking reactions of PVA and SP with dialdehydes were confirmed by Fourier transform infrared (FTIR) spectroscopy. Tensile test and boiling water shrinkage measurements showed that the physical properties of PVA/SP fibers crosslinked by dialdehydes were improved comparing with those formalized fibers.
文摘The effects of Ethylene-Vinyl Acetate copolymer （EVA） latex as an additive or a glass fiber surface modifier on the properties of Glass-Fiber （ GF ）/ Magnesium Oxychloride Cement （MOC） composites was studied. The mechanical properties, water resistance aud aging resistance of the cured GF/ MOC composites were estimated and chemical ingredients analysis and morphological study of the GF/ MOC composites were also performed. It is found that EVA added to the MOC matrix could substantially improve the interfacial adhesion, water resistance aud aging resistance of GF/ MOC composites. EVA treatment on glass fibers resulted in decreasing initial flexural strength of GF/ MOC composites while enhancing the soft coefficients. In addition, the drying time and dilution of the EVA treatment on glass fibers also had an otwioas effect on the properties of GF/ MOC composites. However, excessive EVA interfered with the growth of the 5 Mg（ OH）2· MgCl2 ·8H2O crystal and the properties of GF / MOC composites.
基金supported by the National Natural Science Foundation of China(No.51103058)the Youth Foundation of Jilin Province(No.201101059)Open Foundation of Key Laboratory of Automobile Materials(Jilin University),Ministry of Education(No.10-450060326014)
文摘PLLA/CA mixtures of different compositions were successfully electrospun to obtain composite nanofibrous membranes. The microstructures of the membrances changed from homogeneous to heterogeneous with the addition of CA, which was observed by FE-ESEM. The PLLA/CA fabric membranes were characterized by mechanical testing, DSC and contact angle measurements. The tensile stress of the composite fibrous membranes increased obviously with the increase of CA content. DSC results indicated that the CA component was the main factor for the changes of enthalpies in the composite fibers. Contact angle measurements showed the hydrophilicity of the electrospun nanofiber membranes was improved with the addition of CA.
基金The authors would like to acknowledge with great gratitude to the supports of the National Natural Science Foundation of China(Grant Nos:11772124 and 11922206)the Science Foundation of Hunan Province(Grant No:2018JJ3027).
文摘Environmental-stimulus-triggered self-folding mechanisms have found promising applications in many engineering fields.Recently,a water-activated self-folding procedure has been designed by using the electrospun polyvinyl acetate(PVAc)fiber mat which contains high tensile residual stresses in the vitrified fibers during the spinning processes.The water permeation initiates plasticization of PVAc fiber mat and leads to a material shrinkage.When water diffusion starts at the top surface of a PVAc sheet,a shrinkage variation along the diffusion pathway forms a bending hinge on the sheet,which has been demonstrated in 3D origami design.To capture the water-triggered plasticization mechanism and chemomechanical coupling deformation compatibility,a consistent finite deformation viscoplastic model is developed for the PVAc fiber mat under coupled chemomechanical loading conditions.The residual stress and‘fixed’strain are modeled through the unrecoverable plastic strain in the PVAc fiber mat.As water permeates into the PVAc fiber mat,the induced increase in mixing entropy lowers the glass transition temperature of the material,and results in a gradual relaxation of the fixed viscoplastic strain.A non-Fickian diffusion model suitable for glassy material is adopted to capture the water permeation in the PVAc fiber mat.After calibrated and validated by a series of experiments,the proposed model is implemented in ABAQUS software to simulate the water-activated self-folding of PVAc sheet.The numerical example for a typical origami design suggests a promising engineering application prospect.
