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81.
CRYSTALLIZATION IN PARTIALLY MOLTEN ORIENTED BLENDS OF POLYCONDENSATES AS REVEALED BY X-RAY STUDIES*
《Journal of Macromolecular Science: Physics》2013,52(5):935-957
Oriented fibers or films of binary polymer blends from polycondensates were investigated by two-dimensional (2D) wide-angle X-ray scattering (WAXS) during the finishing process of microfibrillar reinforced composite (MFC) preparation, that is, heating to a temperature between the melting temperatures of the two components, isothermal annealing, and subsequent cooling. It is shown that the crystallization behavior in such MFC from polycondensates depends not only on the blend composition, but also on thermal treatment conditions. Poly(ethylene terephthalate)/polyamide 12 (PET/PA12), poly(butylene terephthalate)/poly(ether ester) (PBT/PEE), and PET/PA6 (polyamide 6) composites were prepared in various compositions from the components. Materials were investigated using rotating anode and synchrotron X-ray source facilities. The effect of the annealing time on the expected isotropization of the lower melting component was studied in the PET/PA6 blend. It was found that PA6 isotropization took place after 2 h; shorter (up to 30 min) and longer (up to 8 h) melt annealing results in oriented crystallization due to different reasons. In PET/PA12 composites, the effect of PA12 transcrystallization with reorientation was confirmed for various blend compositions. The relative strength of the effect decreases with progressing bulk crystallization. Earlier presumed coexistence of isotropic and highly oriented crystallites of the same kind with drawn PBT/PEE blend was confirmed by WAXS from a synchrotron source. 相似文献
82.
采用SE- 30毛细柱、FID、程序升温气相色谱法分析了TAME合成原料及产品的C5组成 ,解析出 C5的8个组分 ;采用 GDX1 0 4填充柱、TCD对含醚产品进行了分析 ,解析出水、甲醇及 TAME。为试验研究和工业生产提供了一种快速准确的方法。 相似文献
83.
Zusammenfassung Es wird eine flüssigkeits-chromatographische Methode vorgestellt, welche die Identifizierung und quantitative Bestimmung von niederen Alkoholen und deren Ethylenoxid-Addukten sowie von niederen Polyolen, Aldehyden und von Harnstoff in wäßrigen Lösungen erlaubt. Die Methode kommt ohne Anreicherungs-oder Derivatisierungsschritte aus, so daß Substanzverluste vor der eigentlichen Chromatographie vermieden sind. Sie wird angewendet bei der Analytik von Reinigungsmitteln unbekanter Zusammensetzung und in der Produktkontrolle.
Three column systems for the analysis of short-chain alcohols, ether-alcohols and aldehydes in cleansing agents
Summary A HPLC method is described which allows the identification and determination of short-chain alcohols and their ethylene oxide adducts as well as of short-chain polyols, aldehydes and urea in aqueous solutions.The method does not necessitate the use of concentration or derivatization techniques; the possible loss of substances before running the chromatogram is thereby avoided. The method is used in the analysis of cleansing agents of unknown composition and for product control.
Herrn Dr. Bruno W. Werdelmann zum 60. Geburtstag gewidmet. 相似文献
84.
Santanu Kumar Pal 《Tetrahedron》2007,63(29):6874-6878
This paper presents an environmentally benign procedure for the preparation of monohydroxy-functionalized triphenylenes using simple ionic reagents. Pyridinium hydrochloride, pyridinium hydrobromide, N-methyl pyridinium iodide, N-ethyl pyridinium bromide, and 1-n-butyl-3-methyl imidazolium bromide have been employed to prepare various monohydroxypentaalkoxytriphenylenes, which are valuable precursors for the synthesis of a variety of discotic monomers, dimers, oligomers, and polymers. 相似文献
85.
Indium(III) chloride is an effective Lewis acid catalyst for one-pot allylation-etherification and reductive etherification of aromatic aldehydes with functional silanes, allyltriethoxysilane, and triethoxysilane, at room temperature to afford corresponding ethers in excellent yields. Additionally, the InCl3-catalyzed reactions in the presence of TMSCl offer significant advantages in its ease of working-up for the preparation of unsymmetrical ethers under mild conditions. 相似文献
86.
87.
Alson MartMysore S. Shashidhar 《Tetrahedron》2012,68(47):9769-9776
The cleavage of propargyl, allyl, benzyl, and PMB ethers by Pd(OH)2/C can be tuned in that order, by varying the reaction conditions. Other moieties such as C-C double bonds, esters, trityl ether, p-bromo and p-nitrobenzyl ethers are stable to these reaction conditions. Cleavage of allyl ethers can be made catalytic by using 1:1 mixture of Pd(OH)2/C and Pd/C. The synthetic potential of the selective ether cleaving ability of Pd(OH)2/C, essentially under neutral conditions, has been demonstrated by an efficient synthesis of a precursor for the preparation of an inositol pyrophosphate derivative. 相似文献
88.
Fengling Zhang Dr. Jingning Lai Zhengqiang Hu Anbin Zhou Huirong Wang Xin Hu Lijuan Hou Bohua Li Wen Sun Dr. Nan Chen Prof. Li Li Prof. Feng Wu Prof. Renjie Chen 《Angewandte Chemie (International ed. in English)》2023,62(16):e202301772
Lithium-oxygen batteries (LOBs) are well known for their high energy density. However, their reversibility and rate performance are challenged due to the sluggish oxygen reduction/evolution reactions (ORR/OER) kinetics, serious side reactions and uncontrollable Li dendrite growth. The electrolyte plays a key role in transport of Li+ and reactive oxygen species in LOBs. Here, we tailored a dilute electrolyte by screening suitable crown ether additives to promote lithium salt dissociation and Li+ solvation through electrostatic interaction. The electrolyte containing 100 mM 18-crown-6 ether (100-18C6) exhibits enhanced electrochemical stability and triggers a solution-mediated Li2O2 growth pathway in LOBs, showing high discharge capacity of 10 828.8 mAh gcarbon−1. Moreover, optimized electrode/electrolyte interfaces promote ORR/OER kinetics on cathode and achieve dendrite-free Li anode, which enhances the cycle life. This work casts new lights on the design of low-cost dilute electrolytes for high performance LOBs. 相似文献
89.
Wei-Hsuan Yang Sachindranath Pal Wen-Shu Hwang Ivan J.B. Lin 《Journal of organometallic chemistry》2008,693(25):3729-3740
Tetra-ether substituted imidazolium salts, LHX (where LH = N,N′-bis(2,2-diethoxyethyl)imidazolium cation and X = Br, BF4, PF6, BPh4, NO3 and NTf2 anions) were derived from imidazole. Attempts to produce aldehyde functionalized imidazolium salt through acid hydrolysis of LHBr resulted an unexpected tetra-hydroxy compound LAHBr and the dialdehyde compound LBHBr. Reaction of LHBr with Ag2O afforded [L2Ag][AgBr2] (1). Mononuclear Pd-complex trans-[L2PdCl2] (2) and dinuclear Pd-complex [(LPdCl2)2] (3) were obtained by 1:1 and 1:2 reaction of in situ generated Ag-carbene with Pd(CH3CN)2Cl2. cis-[LPdPPh3Cl2] (4) was synthesized from reaction of PPh3 with dinuclear complex 3. Hydrolysis of 3 under acidic conditions also generates a hydroxy derivative 3A and the aldehyde derivative 3B. Direct heating of LHBr with Ni(OAc)2 · 4H2O at 120 °C under vacuum generated trans-[L2NiBr2] (5). These complexes were characterized by NMR, mass, elemental analysis, and X-ray single crystal diffraction analysis. Pd--Pd interaction was observed in 3. All the Pd complexes exhibited excellent catalytic activity in Heck reaction. 相似文献
90.
Synthese und Struktur der Kronenetherkomplexe von Kaliumhexachlorodipalladat(II) und -diplatinat(II)
Synthesis and Structure of Crown Ether Complexes of Potassium Hexachlorodipalladate(II) and -diplatinate(II) K2[MCl4] (M ? Pd, Pt) reacts with an excess of crown ether 18-crown-6 in water to give the crown ether complexes of potassium hexachlorodipalladate(II) and -diplatinate(II) [K(18-cr-6)]2[M2Cl6] (M ? Pd, 1 ; M ? Pt, 3 ), respectively, and in methylene chloride to give those of potassium tetrachloropalladate(II) and -platinate(II) [K(18-cr-6)]2[MCl4] ( 1 ) (M ? Pd, 2 ; M ? Pt, 4 ), respectively. 1 - 4 are characterized by microanalysis, NMR (1H, 13C), and vibrational spectroscopy. The X-ray structure analyses of the isotypic complexes 1 (P21/c; a = 10,9678(8), b = 8,2991(7), c = 22,469(2) Å, β = 98,523(5)°; Z = 2) and 3 (P21/c; a = 10,934(3), b = 8.376(3), c = 22,410(5) Å, β = 98,77(3)°; Z = 2) reveal [M2Cl6]2? anions of nearly D2h symmetry and [K(18-cr-6)]+ cations, in which the distance of K+ to the mean plane of the crown ether defined by its six oxygen atoms amounts to 0,830(4) Å in 1 and 0,821(2) Å in 3 , respectively. There are tight contacts between cations and anions (d(K-Cl): 3,341(2)/3,260(2) Å ( 1 ); 3,348(4)/3,259(4) Å ( 3 )). 相似文献