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991.
We designed multiblock amphiphiles AmF and AmH , which consist of perfluorinated and non-fluorinated hydrophobic units, respectively. Absorption spectroscopy revealed that both amphiphiles are molecularly dispersed in organic solvent, while they form aggregates under aqueous conditions. Furthermore, we investigated whether AmF and AmH can be incorporated into DOPC lipid bilayer membranes, and found that the maximum concentration of AmF that can be incorporated into DOPC lipid bilayer membranes is 43 times higher than that of AmH . 相似文献
992.
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994.
《Journal of polymer science. Part A, Polymer chemistry》2018,56(1):25-37
A new bisphenol monomer containing a pair of electron‐rich tetra‐arylmethane units was designed and synthesized. Based on this monomer, along with commercial 4,4′‐(hexafluoroisopropylidene)diphenol A and 4,4′‐difluorobenzophenone, a series of novel poly(arylene ether ketone)s containing octasulfonated segments of varying molar percentage (x) (6F‐SPAEK‐x) were successfully synthesized by polycondensation reactions, followed by sulfonation. Tough, flexible, and transparent membranes, exhibiting excellent thermal stabilities and mechanical properties were obtained by casting. 6F‐SPAEK‐x samples exhibited appropriate water uptake and swelling ratios at moderate ion exchange capacities (IECs) and excellent proton conductivities. The highest proton conductivity (215 mS cm−1) is observed for hydrated 6F‐SPAEK‐15 (IEC = 1.68 meq g−1) at 100 °C, which is more than 1.5 times that of Nafion 117. Furthermore, the 6F‐SPAEK‐10 membrane exhibited comparable proton conductivity (102 mS cm−1) to that of Nafion 117 at 80 °C, with a relatively low IEC value (1.26 meq g−1). Even under 30% relative humidity, the 6F‐SPAEK‐20 membrane (2.06 meq g−1) showed adequate conductivity (2.1 mS cm−1) compared with Nafion 117 (3.4 mS cm−1). The excellent comprehensive properties of these membranes are attributed to well‐defined nanophase‐separated structures promoted by strong polarity differences between highly ionized and fluorinated hydrophobic segments. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 25–37 相似文献
995.
Frontispiece: Matrix‐Free DNP‐Enhanced NMR Spectroscopy of Liposomes Using a Lipid‐Anchored Biradical
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996.
Namiko Fukuzaki Kazuhiro Nakabayashi Satoshi Nakazawa Shigeaki Murata Tomoya Higashihara Mitsuru Ueda 《Journal of polymer science. Part A, Polymer chemistry》2011,49(1):93-100
A novel highly phosphonated poly(N‐phenylacrylamide) ( PDPAA ) with an ion‐exchange capacity (IEC) of 6.72 mequiv/g was synthesized by the radical polymerization of N‐[2,4‐bis(diethoxyphosphinoyl)phenyl]acrylamide ( DEPAA ), followed by the hydrolysis with trimethylsilyl bromide. Then, the crosslinked PDPAA membrane was successfully prepared by the electrophilic substitution reaction between the aromatic rings of PDPAA and the carbocation formed from hexamethoxymethylmelamine (CYMEL) as a crosslinker in the presence of methanesulfonic acid. The crosslinked PDPAA membrane had high oxidative stability against Fenton's reagent at room temperature. The proton conductivity of the crosslinked PDPAA membrane was 8.8 × 10?2 S/cm at 95% relative humidity (RH) and 80 °C, which was comparable to Nafion 112. Under low RH, the crosslinked PDPAA membrane showed the proton conductivity of 1.9 × 10?3 and 4.7 × 10?5 S/cm at 50 and 30% RH, respectively. The proton conductivity of the crosslinked PDPAA membrane lied in the highest class among the reported phosphonated polymers, and, consequently, the very high local concentration of the acids of PDPAA (IEC = 6.72 mequiv/g) achieved high and effective proton conduction under high RH. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
997.
Joseph V. Alexander James W. Neely Eric A. Grulke 《Journal of Polymer Science.Polymer Physics》2014,52(20):1366-1373
Chemical treatment of polymeric hollow fiber membranes (HFMs) is used to prepare their exterior surfaces for coatings. Typical treatments can cleave both C? C and C? H bonds of polypropylene, leading to lower mechanical strength of the fibers. This study evaluated the yield strength, maximum strain, ultimate tensile strength, and burst strength of HFMs treated with each of three common oxidizing reagents: ozone as a gas phase system, aqueous solutions of potassium persulfate, and ammonium persulfate for liquid phase systems. The yield strength and ultimate tensile strength of HFMs decreased continuously with increasing ozonation time. Batch treatments with aqueous oxidizing systems showed limiting values of the yield and ultimate tensile strengths with time. Swelling the hollow fibers with methanol prior to oxidation caused less reduction of the mechanical properties after persulfate treatment. Fibers pretreated with methanol showed lower losses of mechanical properties strength with aqueous oxidation systems. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1366–1373 相似文献
998.
本文介绍了高温云纹实验的背景,详细叙述了高温实验专用炉设计原理和控温系统,解决了紊流的影响,在高温下可获得清晰稳定的图像。控温系统以8031单片机为基础,采用了三次回归方程计算测量温度,运用PID调节控制,提高了高温实验炉的可靠性。 相似文献
999.
Y.?MurakamiEmail author Y.?Murakami K.?Naito T.?Itoh T.?Kobayashim N.?Fujii 《Shock Waves》2003,13(2):149-154
Oxidation of cyclo-C5H5 was investigated by monitoring O atoms and also CO molecules behind the reflected shock of cyclo-C5H6 / O2 /Ar and C6H5OCH3 /O2 /Ar mixtures. In both mixtures we could observe the formation of O atoms produced by the reaction of cyclo-C5H5 + O
cyclo-C5H5O + O and from the kinetic analysis of these time profiles the rate constant for this reaction was determined to be
kJ/RT) cm3 mol-1 s-1. The possibility of CO formation by the reaction of cyclo-C5H5O
C4H5 + CO was also investigated but because of the subsequent reactions forming CO molecules no direct information for the reaction of cyclo-C5H5O
C4H5 + CO was derived.Received: 3 February 2003, Accepted: 17 June 2003, Published online: 5 August 2003 相似文献
1000.