- Controlled functionalization of poly(4-methyl-1-pentene) films for high energy storage applications
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A new family of poly(4-methyl-1-pentene) ionomer [PMP-(NH3)xA-y] (x = 1, 2, 3 and A = Cl-, SO42-, PO43-, y = NH3 content) modified (NH3+)xAx- ionic groups has been synthesized. The ionomers were synthesised using either a traditional Ziegler-Natta or a metallocene catalyst for the copolymerisation of 4-methyl-1-pentene and bis(trimethylsilyl)amino-1-hexene. A systematic study was conducted on the effect of the subsequent work-up procedures that can prevent undesirable side reactions during the synthesis of the [PMP-(NH3)xA-y] ionomers. The resulting PMP-based copolymers were carefully monitored by a combination of nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), mechanical properties, dielectric properties, and electric displacement-electric field (D-E) hysteresis loop measurements. Our results reveal that the [PMP-(NH3)xA-y] ionomer films show a significantly enhanced dielectric constant (~5) and higher breakdown field (~612 MV m-1) as compared with pure PMP films. Additionally, these PMP-based films show good frequency and temperature stabilities (up to 160 °C). A reliable energy storage capacity above 7 J cm-3 can be obtained, and is twice the energy storage capacity of state-of-the-art biaxially oriented polypropylene films, which can be attractive for technological applications for energy storage devices.
- Zhang, Min,Zhang, Lin,Zhu, Meng,Wang, Yiguang,Li, Nanwen,Zhang, Zhijie,Chen, Quan,An, Linan,Lin, Yuanhua,Nan, Cewen
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- New polyethylene based anion exchange membranes (PE-AEMs) with high ionic conductivity
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This paper discusses a new class of high performance polyethylene-based anion exchange membranes (PE-AEMs) that contain a wide concentration range of pendant (flexible) ammonium chloride (NR3+Cl-) groups and with or without a cross-linked PE matrix structure. The chemistry involves a metallocene-mediated polymerization of ethylene, silane-protected α,ω-amino-olefin [CxN(SiMe3)2], with or without styrenic diene (cross-linker), to form ethylene/C xN(SiMe3)2 copolymers and ethylene/C xN(SiMe3)2/diene terpolymers, respectively. The resulting co- and ter-polymers were completely soluble in common organic solvents and were solution-casted into uniform films (thickness, 50-70 μm; without backing material) and then thermal cross-linked in ethylene/C xN(SiMe3)2/diene case, further interconverting the silane-protected amino groups into the desired -NR3 +Cl- groups (R: H, CH3, and C3H 7) under solid state conditions. The resulting PE-NR3 +Cl- and cross-linked x-PE-N(CH3) 3+Cl- membranes were systematically studied to understand how the PE structure (-NR3+Cl- concentration, R group, cross-linking density, etc.) affects ionic conductivity, water uptake, film stability, and ion selectivity. For comparison, several commercially available AEMs were also examined. Evidently, an x-PE-N(CH 3)3+Cl- membrane, with 28.1 mol % -N(CH3)3+Cl- groups and 0.2 mol % cross-linkers, shows moderate water swelling and outperforms all commercial membranes with exceptionally high ionic conductivities of 119.6 mS/cm in 2 N HCl solution and 78.8 mS/cm in 2 N HCl-0.2N CuCl solution at room temperature.
- Zhang, Min,Kim, Hyung Kyu,Chalkova, Elena,Mark, Fedkin,Lvov, Serguei N.,Chung, T. C. Mike
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- Catalytic Asymmetric Synthesis of Unprotected β2-Amino Acids
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We report here a scalable, catalytic one-pot approach to enantiopure and unmodified β2-amino acids. A newly developed confined imidodiphosphorimidate (IDPi) catalyzes a broadly applicable reaction of diverse bis-silyl ketene acetals with a silylated aminomethyl ether, followed by hydrolytic workup, to give free β2-amino acids in high yields, purity, and enantioselectivity. Importantly, both aromatic and aliphatic β2-amino acids can be obtained using this method. Mechanistic studies are consistent with the aminomethylation to proceed via silylium-based asymmetric counteranion-directed catalysis (Si-ACDC) and a transition state to explain the enantioselectivity is suggested on the basis of density functional theory calculation.
- Zhu, Chendan,Mandrelli, Francesca,Zhou, Hui,Maji, Rajat,List, Benjamin
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supporting information
p. 3312 - 3317
(2021/04/07)
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- Metallocene-mediated synthesis of chain-end functionalized polypropylene and application in PP/clay nanocomposites
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This paper summarizes our research in the preparation of chain end functionalized isotactic polypropylene (PP) having a terminal functional group, such as Cl, OH, and NH2. The chemistry involves metallocene-mediated propylene polymerization usi
- Chung
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p. 6292 - 6299
(2007/10/03)
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- End Coupling of Block Copolymer Nanotubes to Nanospheres
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Triblock copolymer nanotubes bearing end-exposed poly(acrylic acid) or PAA core chains were prepared. The exposed PAA chains were reacted by amidization with a large excess of polystyrene spacer chains possessing amino end groups or amino-containing end b
- Liu, Guojun,Yan, Xiaohu,Li, Zhao,Zhou, Jiayun,Duncan, Scott
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p. 14039 - 14045
(2007/10/03)
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- Exfoliated PP/Clay Nanocomposites Using Ammonium-Terminated PP as the Organic Modification for Montmorillonite
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The applications of chain end-functionalized polypropylene (PP) in polyolefin/clay nanocomposites were discussed. Transmission electron microscopy (TEM) was used to examine the degree of exfoliated structure. The side chain-functionalized or block copolym
- Wang,Nakajima,Manias,Chung
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p. 8919 - 8922
(2007/10/03)
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- Termination of living anionic polymerizations using chlorosilane derivatives. A general synthetic methodology for the synthesis of end-functionalized polymers
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The transformation of living polymer chain ends is the most widely used technique to synthesize end-functionalized polymeric materials. Herein we report the development of a new synthetic methodology which is able to give very high degrees of functionalization to living anionic polymer chains. This methodology is based on termination reactions with chlorosilane derivatives containing protected functional groups and is described with particular emphasis on the introduction of primary aliphatic amines and primary emphasis on the introduction of primary aliphatic amines and primary aliphatic alcohols. The extent of functionalization was verified by using conventional techniques such as gel permeation chromatography (GPC), end group titration, multinuclear magnetic resonance spectroscopy, and TLC, but was also examined by using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The usefulness of these materials for construction of supramolecular assemblies is illustrated by the coupling of the polymeric amine to [Ru(bpy)2(4-CH34′-CO2Hbpy)]-(PF6)2 (bpy - 2,2′-bipyridine).
- Peters,Belu,Linton,Dupray,Meyer,DeSimone
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p. 3380 - 3388
(2007/10/02)
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- Silylated Amines II. A New, Highly Variable Amine Synthesis by the N,N-Bis(trimethylsilyl)aminomethylation of Grignard Compounds
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Sodium bis(trimethylsilyl)amide reacts with chloromethyl methylether (1) to form methoxy-N,N-bis(trimethylsilyl)aminomethane (3), which effects the aminomethylation of Grignard compounds 4 to form N,N-bis(trimethylsilyl)amines 5.
- Betsmann, Hans Juergen,Woelfel, Gerhard,Mederer, Karl
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p. 848 - 850
(2007/10/02)
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- Aminomethylation secondaire ou primaire d'organoaluminiques α-insatures a l'aide de gem-aminoethers N-trimethylsilyles: synthese d'amines secondaires ou primaires, β-ethyleniques, β-acetyleniques ou α-alleniques
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Organoaluminium compounds prepared from allylic or propargylic halides react easily with N-trimethylsilyl or N,N-bis(trimethylsilyl) gem-aminoethers to afford in a one-pot reaction unsaturated secondary (with tertiary alkyl group) or primary amines.
- Courtois, G.,Mesnard, D.,Dugue, B.,Miginiac, L.
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- Primary Aminomethylation at the α-Position of Carboxylic Acids and Esters. Trimethylsilyl Triflate-Catalyzed Reaction of Ketene Silyl Acetals with N,N-Bis(trimethylsilyl)methoxymethylamine
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A new, general method for the synthesis of β-aminocarboxylic esters (9) and acids (10) was developed.The introduction of primary aminomethyl unit at the α-position of carboxylic esters (2) and acids (3) was achieved in high yields by the silyl trifluorome
- Okano, Kohji,Morimoto, Toshiaki,Sekiya, Minoru
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p. 2228 - 2234
(2007/10/02)
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- N,N-Bis(trimethylsilyl)methoxymethylamine as a Convenient Synthetic Equivalent for +CH2NH2: Primary Aminomethylation of Organometallic Compounds
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The introduction of the primary aminomethyl unit at carbon through N,N-bis(trimethylsilyl)aminomethylation of Grignard and organolithium compounds can be achieved in good yield using N,N-bis(trimethylsilyl)methoxymethylamine (1).
- Morimoto, Toshiaki,Takahashi, Toshio,Sekiya, Minoru
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p. 794 - 795
(2007/10/02)
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