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Synthesis of partially fluorinated poly(arylene ether sulfone) multiblock copolymers bearing perfluorosulfonic functions 下载免费PDF全文
Luca Assumma Cristina Iojoiu Régis Mercier Sandrine Lyonnard Huu Dat Nguyen Emilie Planes 《Journal of polymer science. Part A, Polymer chemistry》2015,53(16):1941-1956
Partially fluorinated poly(arylene ether sulfone) multiblock copolymers bearing perfluorosulfonic functions (ps‐PES‐FPES), with ionic exchange capacity (IEC) ranging between 0.9 and 1.5 meq H+/g, are synthesized by regioselective bromination of partially fluorinated poly(arylene ether sulfone) multiblock copolymers (PES‐FPES), followed by Ullman coupling reaction with lithium 1,1,2,2‐tetrafluoro‐2‐(1,1,2,2‐tetrafluoro‐2‐iodoethoxy)ethanesulfonate. The PES‐FPES are prepared by aromatic nucleophilic substitution reaction by an original approach, that is, “one pot two reactions synthesis.” The chemical structures of polymers are analyzed by 1H and 19F NMR spectroscopy. The resulted ionomers present two distinct glass transitions and α relaxations revealing phase separation between the hydrophilic and the hydrophobic domains. The phase separation is observed at much lower block lengths of ps‐PES‐FPES as compared with the literature. AFM and SANS observations supported the phase separation, the hydrophilic domains are well dispersed but the connectivity to each other depends on the ps‐PES block lengths. The thermomechanical behavior, the water up‐take, and the conductivity of the ps‐PES‐FPES membranes are compared with those of Nafion 117® and randomly functionalized polysulfone (ps‐PES). Conductivities close or higher to those of Nafion 117® are obtained. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1941–1956 相似文献
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A metabolic pathway is a set of enzyme catalysed biochemical reactions by which a living organism transforms an initial (source) compound into a final (target) compound. Path finding approaches to metabolic pathways adopt a graph theory approach to the problem of determining the reactions an organism might use to transform a source compound into a target compound. In this paper, the effectiveness of using compound node connectivities in a path finding approach is examined. An approach to path finding based upon integer programming is also presented. 相似文献
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We present a new branch and bound algorithm for weighted Max-SAT, called Lazy which incorporates original data structures and inference rules, as well as a lower bound of better quality. We provide experimental
evidence that our solver is very competitive and outperforms some of the best performing Max-SAT and weighted Max-SAT solvers
on a wide range of instances. 相似文献
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Opeil CP Mihaila B Schulze RK Mañosa L Planes A Hults WL Fisher RA Riseborough PS Littlewood PB Smith JL Lashley JC 《Physical review letters》2008,100(16):165703
Ultraviolet-photoemission (UPS) measurements and supporting specific-heat, thermal-expansion, resistivity, and magnetic-moment measurements are reported for the magnetic shape-memory alloy Ni2MnGa over the temperature range 100T(PM) is due to the Ni d minority-spin electrons. Below T(M) this peak disappears, resulting in an enhanced density of states at energies around 0.8 eV. This enhancement reflects Ni d and Mn d electronic contributions to the majority-spin density of states. 相似文献
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Coneo-Rodríguez Rusbel Baena-Moncada Angélica Acevedo Diego F. Morales Gustavo M. Planes Gabriel A. Barbero Cesar A. 《Journal of Solid State Electrochemistry》2018,22(4):1257-1267
Journal of Solid State Electrochemistry - The performance of electrodes modified with electrochemically generated cobalt oxide nanoparticles for the oxidation of As(III) species was investigated by... 相似文献
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Baena-Moncada Angélica María Coneo-Rodríguez Rusbel La Rosa-Toro Adolfo Pastor Elena Barbero Cesar Planes Gabriel Ángel 《Journal of Solid State Electrochemistry》2019,23(9):2683-2693
Journal of Solid State Electrochemistry - A new family of PtFe catalysts supported on hierarchical porous carbon (HPC), with different porous sizes, was developed and tested as cathodes in oxygen... 相似文献
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