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1.
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
2.
Using a double Suzuki cross-coupling reaction ortho- or para-bromobenzyl bromides are easily transformed into unsymmetrical diaryl (or heteroaryl) methanes 相似文献
3.
A palladium‐TPPTS catalyst heterogenized on KF/alumina has been shown to be effective and recyclable for the selective formation of monooctadienylxylopyranosides via the telomerization of butadiene with D ‐xylose. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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The purpose of this paper is to establish universality of the fluctuations of the largest eigenvalue for some non-necessarily
Gaussian complex Deformed Wigner Ensembles. The real model is also considered. Our approach is close to the one used by A.
Soshnikov (cf. [11]) in the investigations of classical real or complex Wigner Ensembles. It is based on the computation of
moments of traces of high powers of the random matrices under consideration. 相似文献
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The Crystal Structure of CsTcO4 CsTcO4 crystallizes orthorhombic with a = 5.727, b = 5.921 and c = 14.34 Å. Z = 4, space group Pnma (Nr. 62, I.T.). The metal positions were refined by single crystal data, the oxygen positions first determined: the CsTcO4 structure is a slight distortion of the scheelite arrangement (parameters: see text). The MADELUNG Part of Lattice Energy, MAPLE, ?Mean Effective Ionic Radii”?, MEIR, and Effective Coordination Numbers, ECoN, are calculated and discussed. 相似文献
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Li2SnO3 crystallises monoclinic, C, with a = 5.295, b = 9.184, c = 10.032 Å and β = 100.13°; Z = 8. The positions of Sn were obtained from PATTERSON maps and the positions of O and Li by FOURIER difference method. Parameters were refined by least squares-method [1462 reflexes (h 01)–(h 71); R = 10.5%]. The average distances of Li? O are 2.07 Å, and 2.20 Å for Sn? O. The Li2SnO3 structure can be derived from the NaCl type: in a cubic closest packing of oxygen 2/3 of the octahedral holes are occupied by lithium and 1/3 by tin. 相似文献
10.
Magnetochemistry of Divalent Silver. New Fluoroargentates(II): Cs2AgF4, Rb2AgF4, and K2AgF4 Hitherto unknown blue compounds Rb2AgF4 and Cs2AgF4 are prepared. Guinier patterns show, that Cs2AgF4 cristallise in the K2NiF4 structure (a = 4.581, c = 14.192 Å). The structure of the Rb-compound is still unknown. The magnetic behaviour of K2AgF4, Rb2AgF4, and Cs2AgF4 is discussed. 相似文献