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  • 1
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Polymer bulletin 40 (1998), S. 741-747 
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In this work, a series of 2,3-O-methylcellulose (MC) with different DS value were prepared. Its phase transition behavior in aqueous solution was studied in terms of DS value, concentration and molecular weight. The the following conclusions were obtained. (1) All the 2,3-O-MC samples show no sol-gel transition in aqueous solution despite the molecular weight. (2) No phase separation was observed for the 2,3-O-MCs with a DS value lower than 1.0, even when the temperature was raised to 95°C. (3) The precipitation temperature is surprisingly different between 2,3-O-MCs. and other MCs possessing comparable total DS value. (4) The precipitation temperature of 2,3-O-MCs depends on the molecular weight rather than on the concentration.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1572-882X
    Keywords: O-methylcellulose ; water solubility ; substituents distribution ; regioselective substitution ; hydrogen bonding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The effect of substituent distribution on the water solubility of O-methylcellulose (MC) was re-examined to elucidate the lower limit of the degree of substitution (DS) in water-soluble MC. To this end, a series of 2,3-MCs which are regioselectively substituted at the C-2 and C-3 hydroxyl groups were prepared by homogeneous methylation. It was found that the lower limit for the DS value of water-soluble 2,3-MC was almost the same as that for MCs having even distributions of substituents along the cellulose chain as well as in the anhydroglucose units.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1572-882X
    Keywords: LiCl/1 ; 3‐dimethy‐2‐imidazolidinone solvent system ; homogeneous cellulose solution ; cellulose acetate ; O‐methylcellulose ; reaction characteristics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In order to elucidate the nature of the LiCl/1,3‐dimethy‐2‐imidazolidinone (DMI) solvent system as one of the homogeneous reaction media of cellulose, cellulose acetate (CA) and O‐methylcellulose (MC) were prepared using this solvent system, and the distribution of substituents within anhydroglucose units was examined by 13C‐NMR. It was found that (i) homogeneous cellulose solutions can be easily prepared by heating 2, 5–12 and 100 parts of weight of cellulose, LiCl, and DMI, respectively, and (ii) the relative reactivity of hydroxyl groups is in the order C‐6 〉 C‐2 〉 C‐3 for both CA and MC. A remarkable feature of this solvent system is that the reaction efficiency in etherification is very high compared with other homogeneous solvent systems.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurde eine Untersuchung über die dünnschicht-chromatographische Trennung von Polybutadienpräparaten mit den drei unterschiedlichen Mikrostrukturen, trans-1,4-, cis-1,4-und 1,2-Vinyl, durchgeführt. Um diese drei Polymerproben chromatographisch zu trennen, wurde ein experimentelles Verfahren ausgearbeitet, bei dem Tetrachlorkohlenstoff und Amylchlorid wechselweise als Laufmittel verwendet wurden. Ferner wurde gezeigt, daß dieses Verfahren in Kombination mit einer zweidimensionalen Entwicklungstechnik eine Auftrennung des ternären Polymergemisches in die einzelnen Komponenten ermöglicht. Dazu wurde das chromatographische Verhalten von sogenannten „equibinären“ Polybutadienen unter Anwendung des bislang ausgearbeiteten Verfahrens untersucht.
    Notes: A study on thin layer chromatographic (TLC) separation of polybutadienes with three different microstructures, namely, trans-1,4, cis-1,4, and 1,2-vinyl, was carried out. An experimental procedure to separate three possible binary mixtures of these polymers into each component species is established in an alternate use of carbon tetrachloride and amyl chloride as developer. Further it is shown that this procedure combined with a two-dimensional TLC development technique allows to separate the ternary polymer mixture into components. In addition, the chromatographic behavior of so-called “equibinary” polybutadienes has been investigated using the technique established so far.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 255-261 
    ISSN: 0887-624X
    Keywords: controlled synthesis ; amphiphilic block copolymer ; pendant glucose residues ; vinyl ether ; living cationic polymerization ; microphase-separated structure ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amphiphilic block copolymers of vinyl ethers (VEs) of the type  - [CH2CH(OCH2CH2OR)]m - [CH2CH(OiBu)]n - were synthesized by living cationic polymerization, where R is a D-glucose residue, and m and n are the degrees of polymerization (m = 20-50; n = 11-89). To obtain them, sequential living block copolymerization of isobutyl vinyl ether (IBVE) and the vinyl ether carrying 1,2:5,6-diisopropylidene-D-glucose residue was conducted by using the HCl adduct of IBVE, CH3CH(OiBu)Cl, as initiator in conjunction with zinc iodide. These precursor block copolymers had a narrow molecular weight distribution (M̄w/M̄n ∼ 1.1) and a controlled composition. Treatment of them with a trifluoroacetic acid/water mixture led to the target amphiphiles. The solubility of the amphiphilic block copolymers in various solvents depended strongly on composition or the m/n ratio. Their solvent-cast thin films were observed, under a transmission electron microscope, to exhibit various microphase-separated surface morphologies such as spheres, cylinders, and lamellae, depending on composition. © 1997 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 751-757 
    ISSN: 0887-624X
    Keywords: controlled synthesis ; glycopolymer ; pendant D-glucosamine residue ; vinyl ether ; living polymerization ; cationic polymerization ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: D-glucosamine-containing glycopolymers with well-controlled structure were synthesized by living cationic polymerization. To this end, D-glucosamine-containing vinyl ether (VE) of the type [CH2(=)CH(OCH2CH2OR)] was prepared, where R denotes a 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimide-β-D-glucopyranoside, i.e., the hydroxyl and amino groups in D-glucosamine residues are protected by acetyl and phthaloyl groups, respectively. It was found that (1) the efficient living cationic polymerization of VE monomer is achieved by a combination of ethylaluminum dichloride (EtAlCl2) with an adduct of trifluoroacetic acid (TFA) and isobutyl VE (IBVE) [CH3CH(OiBu)OCOCF3] (i.e., TFA/EtAlCl2 initiating system); and (2) the polymerization in toluene at the elevated temperature (0°C) is most suitable to proceed the homogeneous polymerization over the whole conversion range. The molecular weight distribution of the resulting polymers was very narrow (\documentclass{article}\pagestyle{empty}\begin{document}$ {\bar M}_w/{\bar M}_n \sim 1.1 $\end{document}). Quantitative deprotection of the resulting precursor polymers was successfully achieved with hydrazine monohydrate to afford the corresponding water-soluble polymers with pendant D-glucosamine residues. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 751-757, 1997
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 3045-3050 
    ISSN: 0887-624X
    Keywords: poly(vinyl alcohol) ; n-butyl boronic acid ; phenyl boronic acid ; complex ; melting temperature ; spinnability ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly(vinyl alcohol) (PVA) was converted into melt flowable derivatives by complexation with a small amount of n-butyl boronic acid (BBA) and phenyl boronic acid (PBA) in dimethylsulfoxide (DMSO), and their thermal properties were examined from a viewpoint of the melt spinning of the complexes. It was found that (1) the melting temperature of the PVA-boronic acid complexes decreases and their degradation temperature increases with increasing the boronic acid content; (2) no gelation occurs for the PVA complexes with BBA and PBA in DMSO; (3) PBA gives a larger melting-temperature depression for PVA than BBA, but the spinnability of the complexes with BBA is much better than that with PBA; and (4) the melt-molded PVA complex fibers can be easily regenerated into PVA fibers with hot water. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3045-3050, 1998
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 2071-2077 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This study concerns the synthesis of poly(vinyl ether)s (VEs) carrying pendant cellobiose heptadecanoate (CHD) residues and their mesomorphic properties examined by DSC, polarization microscopy and X-ray diffraction. The poly(VE)s were synthesized through cationic polymerization of a CHD-substituted VE, i.e., 10-(vinyloxy)decyl-2,2′,3,3′,4′,6,6′-hepta-O-decanoyl-β-D-cellobioside. From X-ray diffraction analyses, the mesophase of the poly(VE) proved to be closely similar to that of the star-shaped triplet derivative. The mesophase is characterized by the following features; (i) it consists of discotic columns built up by a regular stacking of the pendant CHD residues, (ii) each polymer main chain is presumed to have an extended conformation due to the periodic stacking of the pendant CHD moieties into a columnar structure, and (iii) each polymer molecule independently forms three discotic columns, which surround the main chain, without any intercalation of the CHD pendants originating from different polymer molecules.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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