A sulfonated poly（ether ether ketone） （SPEEK） membrane with a fairly high degree of sulfonation （DS） can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalize...A sulfonated poly（ether ether ketone） （SPEEK） membrane with a fairly high degree of sulfonation （DS） can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalized silica powder with sulfonic acid groups （SiOx-S） was added into the SPEEK matrix （DS = 55.1%） to prepare SPEEK/ SiOx-S composite membranes. The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder. Pure SPEEK membrane swelled 52.6% at 80℃, whereas the SPEEK/SiOx-S （15%, by mass） membrane swelled only 27.3% at the same temperature. From room temperature to 80℃, all SPEEK/SPEEK/SiOx-S composite membranes had methanol permeability of about one order of magnitude lower than that ofNafion115. Compared with pure SPEEK membranes, the addition of the SiOx-S powder not only leads to higher proton conductivity, but also increases the dimensional stability at higher temperatures, and greater proton conductivity can be achieved at higher temperature. The SPEEK/SiO4-S （20%, by mass） membrane could withstand temperature up to 145℃, at which in 100% relative humidity （RH） its proton conductivity exceeded slightly that of Nafion 1 15 membrane and reached 0.17 S·cm^-1, while pure SPEEK membrane dissolved at 90℃. The SPEEK/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.展开更多
A group of poly (phthalazinone ether sulfone ketone)/potassium-titanate-whisker (PPSEK/whisker) composites was prepared by coprecipitation from solution. The whisker surface was modified using titanate coupling agent ...A group of poly (phthalazinone ether sulfone ketone)/potassium-titanate-whisker (PPSEK/whisker) composites was prepared by coprecipitation from solution. The whisker surface was modified using titanate coupling agent prior to blending. The tensile, impact, morphology and thermal properties of the moulded composites were investigated. The measurements showed that the tensile strength and impact strength of the composites increased with increasing whiskers content up to 10 to 20 phr, thereafter they showed a decrease in the whiskers content reached 40 phr. At the same time, the modulus of the composites increased with increasing whiskers content. Scanning electron microscopy studies revealed that the whiskers within the composites were dispersed uniformly by treated with coupling agent. Finally, thermogravimetric analysis showed that the heat resistance of the composites tended to increase with increasing whisker content. The results were analysed and discussed in terms of established models of the behaviour of short-fiber reinforced composites.展开更多
Sulfonated poly(ether ether ketone)(SPEEK)is a very promising alternative membrane material for direct methanol fuel cells.However,with a fairly high degree of sulfonation(DS),SPEEK membranes can swell excessively and...Sulfonated poly(ether ether ketone)(SPEEK)is a very promising alternative membrane material for direct methanol fuel cells.However,with a fairly high degree of sulfonation(DS),SPEEK membranes can swell excessively and even dissolve at high temperature.This restricts mem-branes from working above a high tolerable temperature to get high proton conductivity.To deal with this contra-dictory situation,insolvable zirconium tricarboxybutyl-phosphonate(Zr(PBTC))powder was employed to make a composite with SPEEK polymer in an attempt to improve temperature tolerance of the membranes.SPEEK/Zr(PBTC)composite membranes were obtained by casting a homogeneous mixture of Zr(PBTC)and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating the solvent at 60℃.Many characteristics were investigated,including thermal stability,liquid uptake,methanol permeability and proton conductivity.Results showed significant improvement not only in tem-perature tolerance,but also in methanol resistance of the SPEEK/Zr(PBTC)composite membranes.The mem-branes containing 30 wt-%,40 wt-% of Zr(PBTC)had their methanol permeability around 10^(-7) cm^(2)·s^(-1) at room temperature to 80℃,which was one order of magnitude lower than that of Nafion H 115.High proton conductivity of the composite membranes,however,could also be achieved from higher temperature applied.At 100% rela-tive humidity,above 90℃ the conductivity of the compo-site membrane containing 40 wt-% of Zr(PBTC)exceeded that of the Nafion H 115 membrane and even reached a high value of 0.36 S·cm^(-1) at 160uC.Improved applicable tem-perature and high conductivity of the composite membrane indicatedits promisingapplication in DMFC operationsat high temperature.展开更多
Studies show that two dimensional(2D)nanomaterial and its hybrid have a great promise in tribology for the special laminar microstructure.However,the majority of performed investigations about 2D graphitic carbon nitr...Studies show that two dimensional(2D)nanomaterial and its hybrid have a great promise in tribology for the special laminar microstructure.However,the majority of performed investigations about 2D graphitic carbon nitride(g-C_(3)N_(4))nanosheets are most focused on energy storage,catalysis,adsorption,rarely tribology.In the present study,g-C_(3)N_(4) supporting mono-dispersed Ag nanoparticle hybrid(g-C_(3)N_(4)/Ag)is prepared,and its microstructure and chemical composition are determined.More specifically,the tribological performance as the lubricating additive of poly phthalazinone ether sulfone ketone(PPESK)composite is investigated using the ball-on-disc friction tester.Moreover,the corresponding enhancement mechanism is well proposed based on the experimental analysis and theoretical simulation.Obtained results show that Ag nanoparticles with a size of about 10-20 nm are homogeneously anchored on g-C_(3)N_(4) nanosheets,favoring for good compatibility between g-C_(3)N_(4)/Ag and PPESK.It is found that when 0.3 wt%of g-C_(3)N_(4)/Ag is added to PPESK,the friction coefficient and wear rate of PPESK decrease by 68.9%and 97.1%,respectively.These reductions are mainly attributed to the synergistic self-lubricating effect of Ag nanoparticles and g-C_(3)N_(4) nanosheet,the formation of transfer film,as well as the limited effect of g-C_(3)N_(4)/Ag on the shear deformation of PPESK composite film.Furthermore,it is found that the proposed g-C_(3)N_(4)/Ag-PPESK composite still keeps reasonable friction-reducing and wear-resistant properties under heavy loads and high rotating speeds.The present study demonstrates that the proposed g-C_(3)N_(4)/Ag hybrid is an excellent lubricating additive for polymer composites.展开更多
With well-defined channels and tunable functionality, metal-organic frameworks （MOFs） have inspired the design of a new class of ion-conductive compounds. In contrast to the extensive studies on proton- conductive M...With well-defined channels and tunable functionality, metal-organic frameworks （MOFs） have inspired the design of a new class of ion-conductive compounds. In contrast to the extensive studies on proton- conductive MOFs and related membranes attractive for fuel cells, rare reports focus on MOFs in preparation of anion exchange membranes. In this study, chloromethylated MIL-101 （Cr） was prepared and incor- porated into chloromethylated poly （ether ether ketone） （PEEK） as a multifunctional filler to prepare imidazolium PEEK/imidazolium MIL-101（Cr） （ImPEEK/ImMIL-101（Cr）） anion exchange membrane after synchronous quaternization. The successful synthesis and chloromethylation of MIL-101（Cr） were veri- fied by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy while the enhanced performance of composite membranes in hydroxide conductivity, mechanical strength and dimensional stability were evaluated by alternating-current impedance, electronic stretching machine and measurement of swelling ratio. Specifically, incorporating 5.0wt% ImMIL-101（Cr） afforded a 71.4% increase in hydroxide conductivity at 20℃, 100% RH. Besides, the composite membranes exhibited enhanced dimensional stability and mechanical strength due to the rigid framework of ImMIL- 101（Cr）. At room temperature and the ImM1L-101（Cr） content of 10wt%, the swelling ratio of the ImPEEK/lmMIL-101（Cr） was 70.04% lower while the tensile strength was 47.5% higher than that of the pure membrane.展开更多
A new interfacial polymerization （IP） procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly（phthalazinone ether sulfone ketone） （PPESK） hollow fiber u...A new interfacial polymerization （IP） procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly（phthalazinone ether sulfone ketone） （PPESK） hollow fiber ultrafiltration （UF） membrane. A hollow fiber composite membrane with good performance was prepared and studied by PT-IR and scanning electron microscopy.展开更多
Low methanol permeability of proton exchange membranes (PEMs) is greatly important for direct methanol fuel cells (DMFCs). Here, sulfonated poly (ether ether ketone) (SPEEK) based semiinterpenetrating polymer networks...Low methanol permeability of proton exchange membranes (PEMs) is greatly important for direct methanol fuel cells (DMFCs). Here, sulfonated poly (ether ether ketone) (SPEEK) based semiinterpenetrating polymer networks (semi-IPNs) are successfully prepared by interpenetrating SPEEK into the in-situ synthesized crosslinking networks. The polymeric networks are formed by the covalent bonds between bromobenzyl groups of bro mo methylated poly (phenylene oxide) and amine groups of diamine linkers as well as the ionic bonds between amine species and sulfonated groups. Two linkers without and with sulfonated groups are applied to fabricate the semi-IPNs. The core properties of the membranes, like phase separation, water uptake, proton conductivity and methanol permeability, are systematically studied and compared. The DMFCs assembled by using the semi-IPN membranes display better performance than Nafion 117 in high concentration methanol solutions. The present work provides a facile way to prepare PEMs with enhanced DMFC performance.展开更多
基金Supported by the State Key Development Program for Basic Research of China （2008CB617502）, the National Natural Science Foundation of China （20606025）, and Program for Changjiang Scholars and Innovative Research Team in University of China （IRT0641）.
文摘A sulfonated poly（ether ether ketone） （SPEEK） membrane with a fairly high degree of sulfonation （DS） can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalized silica powder with sulfonic acid groups （SiOx-S） was added into the SPEEK matrix （DS = 55.1%） to prepare SPEEK/ SiOx-S composite membranes. The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder. Pure SPEEK membrane swelled 52.6% at 80℃, whereas the SPEEK/SiOx-S （15%, by mass） membrane swelled only 27.3% at the same temperature. From room temperature to 80℃, all SPEEK/SPEEK/SiOx-S composite membranes had methanol permeability of about one order of magnitude lower than that ofNafion115. Compared with pure SPEEK membranes, the addition of the SiOx-S powder not only leads to higher proton conductivity, but also increases the dimensional stability at higher temperatures, and greater proton conductivity can be achieved at higher temperature. The SPEEK/SiO4-S （20%, by mass） membrane could withstand temperature up to 145℃, at which in 100% relative humidity （RH） its proton conductivity exceeded slightly that of Nafion 1 15 membrane and reached 0.17 S·cm^-1, while pure SPEEK membrane dissolved at 90℃. The SPEEK/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.
基金the National Natural Science Foundation of China under grant No.59473901 Educational Office Fesearch Project of Liaoning Provice under grant No.2020701095.
文摘A group of poly (phthalazinone ether sulfone ketone)/potassium-titanate-whisker (PPSEK/whisker) composites was prepared by coprecipitation from solution. The whisker surface was modified using titanate coupling agent prior to blending. The tensile, impact, morphology and thermal properties of the moulded composites were investigated. The measurements showed that the tensile strength and impact strength of the composites increased with increasing whiskers content up to 10 to 20 phr, thereafter they showed a decrease in the whiskers content reached 40 phr. At the same time, the modulus of the composites increased with increasing whiskers content. Scanning electron microscopy studies revealed that the whiskers within the composites were dispersed uniformly by treated with coupling agent. Finally, thermogravimetric analysis showed that the heat resistance of the composites tended to increase with increasing whisker content. The results were analysed and discussed in terms of established models of the behaviour of short-fiber reinforced composites.
基金Science Foundation of China(The Youth Fund)(20606025)the science and technology development plan of Tianjin(05YFJZCOO600)Program fro Changjiang Scholars and Innova-tive Research Team in University(PCSIRT)for financial support.
文摘Sulfonated poly(ether ether ketone)(SPEEK)is a very promising alternative membrane material for direct methanol fuel cells.However,with a fairly high degree of sulfonation(DS),SPEEK membranes can swell excessively and even dissolve at high temperature.This restricts mem-branes from working above a high tolerable temperature to get high proton conductivity.To deal with this contra-dictory situation,insolvable zirconium tricarboxybutyl-phosphonate(Zr(PBTC))powder was employed to make a composite with SPEEK polymer in an attempt to improve temperature tolerance of the membranes.SPEEK/Zr(PBTC)composite membranes were obtained by casting a homogeneous mixture of Zr(PBTC)and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating the solvent at 60℃.Many characteristics were investigated,including thermal stability,liquid uptake,methanol permeability and proton conductivity.Results showed significant improvement not only in tem-perature tolerance,but also in methanol resistance of the SPEEK/Zr(PBTC)composite membranes.The mem-branes containing 30 wt-%,40 wt-% of Zr(PBTC)had their methanol permeability around 10^(-7) cm^(2)·s^(-1) at room temperature to 80℃,which was one order of magnitude lower than that of Nafion H 115.High proton conductivity of the composite membranes,however,could also be achieved from higher temperature applied.At 100% rela-tive humidity,above 90℃ the conductivity of the compo-site membrane containing 40 wt-% of Zr(PBTC)exceeded that of the Nafion H 115 membrane and even reached a high value of 0.36 S·cm^(-1) at 160uC.Improved applicable tem-perature and high conductivity of the composite membrane indicatedits promisingapplication in DMFC operationsat high temperature.
基金This work was financially supported by the Project of Jiangsu Provincial Six Talent Peak(No.XCL-214)Foundation of State Key Laboratory of Solid lubrication(No.LSL-1709)Senior Intellectuals Fund of Jiangsu University(No.13JDG099).
文摘Studies show that two dimensional(2D)nanomaterial and its hybrid have a great promise in tribology for the special laminar microstructure.However,the majority of performed investigations about 2D graphitic carbon nitride(g-C_(3)N_(4))nanosheets are most focused on energy storage,catalysis,adsorption,rarely tribology.In the present study,g-C_(3)N_(4) supporting mono-dispersed Ag nanoparticle hybrid(g-C_(3)N_(4)/Ag)is prepared,and its microstructure and chemical composition are determined.More specifically,the tribological performance as the lubricating additive of poly phthalazinone ether sulfone ketone(PPESK)composite is investigated using the ball-on-disc friction tester.Moreover,the corresponding enhancement mechanism is well proposed based on the experimental analysis and theoretical simulation.Obtained results show that Ag nanoparticles with a size of about 10-20 nm are homogeneously anchored on g-C_(3)N_(4) nanosheets,favoring for good compatibility between g-C_(3)N_(4)/Ag and PPESK.It is found that when 0.3 wt%of g-C_(3)N_(4)/Ag is added to PPESK,the friction coefficient and wear rate of PPESK decrease by 68.9%and 97.1%,respectively.These reductions are mainly attributed to the synergistic self-lubricating effect of Ag nanoparticles and g-C_(3)N_(4) nanosheet,the formation of transfer film,as well as the limited effect of g-C_(3)N_(4)/Ag on the shear deformation of PPESK composite film.Furthermore,it is found that the proposed g-C_(3)N_(4)/Ag-PPESK composite still keeps reasonable friction-reducing and wear-resistant properties under heavy loads and high rotating speeds.The present study demonstrates that the proposed g-C_(3)N_(4)/Ag hybrid is an excellent lubricating additive for polymer composites.
基金supported by the National Science Fund for Distinguished Young Scholars(21125627)the National Natural Science Founds of China(21490583 and 21621004)the Program of Introducing Talents of Discipline to Universities(B06006).
文摘With well-defined channels and tunable functionality, metal-organic frameworks （MOFs） have inspired the design of a new class of ion-conductive compounds. In contrast to the extensive studies on proton- conductive MOFs and related membranes attractive for fuel cells, rare reports focus on MOFs in preparation of anion exchange membranes. In this study, chloromethylated MIL-101 （Cr） was prepared and incor- porated into chloromethylated poly （ether ether ketone） （PEEK） as a multifunctional filler to prepare imidazolium PEEK/imidazolium MIL-101（Cr） （ImPEEK/ImMIL-101（Cr）） anion exchange membrane after synchronous quaternization. The successful synthesis and chloromethylation of MIL-101（Cr） were veri- fied by transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy while the enhanced performance of composite membranes in hydroxide conductivity, mechanical strength and dimensional stability were evaluated by alternating-current impedance, electronic stretching machine and measurement of swelling ratio. Specifically, incorporating 5.0wt% ImMIL-101（Cr） afforded a 71.4% increase in hydroxide conductivity at 20℃, 100% RH. Besides, the composite membranes exhibited enhanced dimensional stability and mechanical strength due to the rigid framework of ImMIL- 101（Cr）. At room temperature and the ImM1L-101（Cr） content of 10wt%, the swelling ratio of the ImPEEK/lmMIL-101（Cr） was 70.04% lower while the tensile strength was 47.5% higher than that of the pure membrane.
文摘A new interfacial polymerization （IP） procedure is developed in order to synthesize polypiperazine-amide thin-film membrane on the inner surface of poly（phthalazinone ether sulfone ketone） （PPESK） hollow fiber ultrafiltration （UF） membrane. A hollow fiber composite membrane with good performance was prepared and studied by PT-IR and scanning electron microscopy.
基金support of the National Natural Science Foundation of China(Nos. 21603197, 21703212,21233006 and 21473164)Natural Science Foundation of Hubei Province of China(No.2016CFB181)+1 种基金Fundamental Research Funds for the Central University, China University of Geosciences (Wuhan)(No. CUGL180403)China University of Geosciences (Wuhan) for the program of Center for Advanced Energy Research and Technologies
文摘Low methanol permeability of proton exchange membranes (PEMs) is greatly important for direct methanol fuel cells (DMFCs). Here, sulfonated poly (ether ether ketone) (SPEEK) based semiinterpenetrating polymer networks (semi-IPNs) are successfully prepared by interpenetrating SPEEK into the in-situ synthesized crosslinking networks. The polymeric networks are formed by the covalent bonds between bromobenzyl groups of bro mo methylated poly (phenylene oxide) and amine groups of diamine linkers as well as the ionic bonds between amine species and sulfonated groups. Two linkers without and with sulfonated groups are applied to fabricate the semi-IPNs. The core properties of the membranes, like phase separation, water uptake, proton conductivity and methanol permeability, are systematically studied and compared. The DMFCs assembled by using the semi-IPN membranes display better performance than Nafion 117 in high concentration methanol solutions. The present work provides a facile way to prepare PEMs with enhanced DMFC performance.
