A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer （SFMC）, sulfonated （poly ether ether ketone） （SPEEK） and I or 5 wt% graphene oxide （GO） was fabricated through ...A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer （SFMC）, sulfonated （poly ether ether ketone） （SPEEK） and I or 5 wt% graphene oxide （GO） was fabricated through a facile solution casting approach. The simple, but effective monomer sulfonation was performed for SFMC to create compact and rigid hydrophobic backbone structures, while conventional random sulfonation was carried-out for SPEEK. Hydrophilic-hydrophobic-hydrophilic structure of SFMC enhances the compatibility with SPEEK and GO and allows for an unprecedented approach to alter me- chanical strength and proton conductivity of ternary hybrid membrane, as verified from universal test machine （UTM） curves and alternating current （AC） impedance plots. The impact of GO integration on the morphology and roughness of hybrid membrane was scrutinized using field emission scanning electron microscope （FE-SEM） and atomic force microscope （AFM）. Ternary hybrid showed uniform intercalation of GO nanosheets throughout the entire surface of membrane with an increased surface roughness of 8.91 nm. The constructed ternary hybrid membrane revealed excellent water absorption, ion exchange capacity and gas barrier properties, while retaining reasonable dimensional stability. The well-optimized ternary hybrid membrane containing 5 wt% GO revealed a maximum proton conductivity of 111.9 mS/cm, which is higher by a factor of two-fold with respect to that of bare SFMC membrane. The maximum PEMFC power density of 528.07mW/cm2 was yielded by ternary hybrid membrane at a load current density of 1321.1 mA/cm2 when operating the cell at 70 ℃ under 100% relative humidity （RH）. In comparison, a maximum power density of only 182.06 mW/cm2 was exhibited by the bare SFMC membrane at a load current density of 455.56 mA/cm2 under same operating conditions.展开更多
Prolonged hydrothermal treatment for sulfonated poly(ether ether ketone) membranes induces mechanical degradation and developing hydrophilic-hydrophobic phase separation, simultaneously. The enhanced phase separation ...Prolonged hydrothermal treatment for sulfonated poly(ether ether ketone) membranes induces mechanical degradation and developing hydrophilic-hydrophobic phase separation, simultaneously. The enhanced phase separation provides incremental proton conductivity to the membranes, whereas mechanical degradation drastically reduces device stability. On this basis, we describe here the effects of two different ex situ aging processes on sulfonated poly(ether ether ketone) membranes: hydrationdehydration cycling and prolonged hydrothermal treatment. Both aged membranes exhibited enhanced phase separation under the hydrated conditions, as characterized by small angle X-ray scattering.However, when the aged membranes were dried again, the nanostructure of the membranes aged via the hydration-dehydration cycling was recoverable, whereas that of the membranes aged via prolonged hydrothermal treatment was irreversible. Furthermore, the two differently aged membranes showed clear differences in thermal, mechanical, and electrochemical properties. Finally, we implemented both aged membranes in fuel cell application. The sample aged via hydration-dehydration cycling maintained its improved cell performance, whereas the sample aged via hydrothermal treatment showed drastically reduced cell performance after durability test for 50 h.展开更多
A novel type of aromatic poly（ ether ether ketone） s with carboxyl groups were prepared by polycondensation of 4,4-bis（4-hydroxyphenyl）pentanoic acid with difluoro-monomers. Their mo- lecular structures were deter...A novel type of aromatic poly（ ether ether ketone） s with carboxyl groups were prepared by polycondensation of 4,4-bis（4-hydroxyphenyl）pentanoic acid with difluoro-monomers. Their mo- lecular structures were determined by ^1H-NMR and IR, respectively. Their molecular weights were measured by gel permeation chromatography （ GPC ）, which showed that all the polymers had high molecule weights （ 〉 42 000）. Due to the long side chains of polymers, all the polymers had good solubility （soluble in NMP, DMAc, THF, etc. ）. The differential scanning calorimeter （DSC） detected their excellent glass transition temperatures （ Tg ） up to 195 ℃. The Tg increased with the content of carboxylic units in the polymer chains, because the interactions of H bonds increased with increasing content of carboxylic. The polymers could form transparent and flexible films, which make them a candidate for membrane materials.展开更多
We synthesized a series of polymers: poly(ether ether ketone ketone) (PEEKK),poly (ether biphenyl ether ketone ketone) (PEBEKK) and their copolymer by polycondensation. We also prepared a series of PEEKK-PEBEKK blends...We synthesized a series of polymers: poly(ether ether ketone ketone) (PEEKK),poly (ether biphenyl ether ketone ketone) (PEBEKK) and their copolymer by polycondensation. We also prepared a series of PEEKK-PEBEKK blends. By using DSC method, we found that Tg of the copolymers and the blends rose with the increasing of biphenyl contents in the polymers. Tc of the copolymers and the blends is higher than the corresponding homopolymer. From the results, we think that PEEKK-PEBEKK copolymer and blends are miscible and the copolymer is random.展开更多
A kind of highly fluorinated bisphenol monomer was synthesized. It was characterized by FTIR, 1H NMR and MS. 6F PEEK and 6F PEEKK were prepared via aromatic nucleophilic substitution, based on [3,5 di(trifluoromethyl)...A kind of highly fluorinated bisphenol monomer was synthesized. It was characterized by FTIR, 1H NMR and MS. 6F PEEK and 6F PEEKK were prepared via aromatic nucleophilic substitution, based on [3,5 di(trifluoromethyl)] phenylhydroquinone and difluoro monomers. The T gs of 6F PEEK and 6F PEEKK are 423 and 436 K, respectively. The 6F polymers exhibit a high thermal stability and good solubility. The flexible, creasable and transparent thin films were easily obtained by compression moulding and solution casting.展开更多
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20164030201070)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and future Planning(NRF-2017R1A2B4005230)
文摘A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer （SFMC）, sulfonated （poly ether ether ketone） （SPEEK） and I or 5 wt% graphene oxide （GO） was fabricated through a facile solution casting approach. The simple, but effective monomer sulfonation was performed for SFMC to create compact and rigid hydrophobic backbone structures, while conventional random sulfonation was carried-out for SPEEK. Hydrophilic-hydrophobic-hydrophilic structure of SFMC enhances the compatibility with SPEEK and GO and allows for an unprecedented approach to alter me- chanical strength and proton conductivity of ternary hybrid membrane, as verified from universal test machine （UTM） curves and alternating current （AC） impedance plots. The impact of GO integration on the morphology and roughness of hybrid membrane was scrutinized using field emission scanning electron microscope （FE-SEM） and atomic force microscope （AFM）. Ternary hybrid showed uniform intercalation of GO nanosheets throughout the entire surface of membrane with an increased surface roughness of 8.91 nm. The constructed ternary hybrid membrane revealed excellent water absorption, ion exchange capacity and gas barrier properties, while retaining reasonable dimensional stability. The well-optimized ternary hybrid membrane containing 5 wt% GO revealed a maximum proton conductivity of 111.9 mS/cm, which is higher by a factor of two-fold with respect to that of bare SFMC membrane. The maximum PEMFC power density of 528.07mW/cm2 was yielded by ternary hybrid membrane at a load current density of 1321.1 mA/cm2 when operating the cell at 70 ℃ under 100% relative humidity （RH）. In comparison, a maximum power density of only 182.06 mW/cm2 was exhibited by the bare SFMC membrane at a load current density of 455.56 mA/cm2 under same operating conditions.
基金Byoungseok Min of Pohang Accelerator Laboratory for SAXS technical support at 4C beamline.All authors have read the manuscript and agreed to its contents。
文摘Prolonged hydrothermal treatment for sulfonated poly(ether ether ketone) membranes induces mechanical degradation and developing hydrophilic-hydrophobic phase separation, simultaneously. The enhanced phase separation provides incremental proton conductivity to the membranes, whereas mechanical degradation drastically reduces device stability. On this basis, we describe here the effects of two different ex situ aging processes on sulfonated poly(ether ether ketone) membranes: hydrationdehydration cycling and prolonged hydrothermal treatment. Both aged membranes exhibited enhanced phase separation under the hydrated conditions, as characterized by small angle X-ray scattering.However, when the aged membranes were dried again, the nanostructure of the membranes aged via the hydration-dehydration cycling was recoverable, whereas that of the membranes aged via prolonged hydrothermal treatment was irreversible. Furthermore, the two differently aged membranes showed clear differences in thermal, mechanical, and electrochemical properties. Finally, we implemented both aged membranes in fuel cell application. The sample aged via hydration-dehydration cycling maintained its improved cell performance, whereas the sample aged via hydrothermal treatment showed drastically reduced cell performance after durability test for 50 h.
基金Supported by Open Project of State Key Laboratory of Supramolecular Structure and Materials(SKLSSM201114)the National Natural Science Foundation of China(51103010)
文摘A novel type of aromatic poly（ ether ether ketone） s with carboxyl groups were prepared by polycondensation of 4,4-bis（4-hydroxyphenyl）pentanoic acid with difluoro-monomers. Their mo- lecular structures were determined by ^1H-NMR and IR, respectively. Their molecular weights were measured by gel permeation chromatography （ GPC ）, which showed that all the polymers had high molecule weights （ 〉 42 000）. Due to the long side chains of polymers, all the polymers had good solubility （soluble in NMP, DMAc, THF, etc. ）. The differential scanning calorimeter （DSC） detected their excellent glass transition temperatures （ Tg ） up to 195 ℃. The Tg increased with the content of carboxylic units in the polymer chains, because the interactions of H bonds increased with increasing content of carboxylic. The polymers could form transparent and flexible films, which make them a candidate for membrane materials.
文摘We synthesized a series of polymers: poly(ether ether ketone ketone) (PEEKK),poly (ether biphenyl ether ketone ketone) (PEBEKK) and their copolymer by polycondensation. We also prepared a series of PEEKK-PEBEKK blends. By using DSC method, we found that Tg of the copolymers and the blends rose with the increasing of biphenyl contents in the polymers. Tc of the copolymers and the blends is higher than the corresponding homopolymer. From the results, we think that PEEKK-PEBEKK copolymer and blends are miscible and the copolymer is random.
文摘A kind of highly fluorinated bisphenol monomer was synthesized. It was characterized by FTIR, 1H NMR and MS. 6F PEEK and 6F PEEKK were prepared via aromatic nucleophilic substitution, based on [3,5 di(trifluoromethyl)] phenylhydroquinone and difluoro monomers. The T gs of 6F PEEK and 6F PEEKK are 423 and 436 K, respectively. The 6F polymers exhibit a high thermal stability and good solubility. The flexible, creasable and transparent thin films were easily obtained by compression moulding and solution casting.
