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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 27 (1981), S. 856-859 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 2 (1947), S. 21-35 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A polyvinyl acetate polymer of medium viscosity was fractionated into sixteen fractions (first series) and three of the larger of these further separated into twenty subfractions (second series). The intrinsic viscosities and the osmotic pressure molecular weights were determined at 25°C. and the relation between them was found to be expressed by the equations: first series: [η] = (1.88 × 10-4) M0.69; second series: [η] = (1.76 × 10-4) M0.68. The data indicate that little, if any, increase in homogeneity is to be expected by further successive fractionations and that the equations applicable to the second fractionation series are representative of essentially homogeneous polyvinyl acetates in acetone. An equation applicable to fractionated and unfractionated vinyl acetate polymers is described that is useful in obtaining the intrinsic viscosity from a single viscosity measurement. Several unfractionated materials from different sources were also studied and the calculated ratios of the viscosity-average to the number-average molecular weight indicate that the degree of heterogeneity of chain-length distribution increases with increasing average molecular weight.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 4 (1949), S. 542-542 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0268-2605
    Keywords: surfactants ; carbohydrate ; carbosilane ; silane ; wetting ; surface tension ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of carbohydrate surfactants bearing carbosilane, silane, polysilane and non-permethylated siloxane moieties is described. These surfactants consist of three structural elements: (1) a silicon-containing moiety, (2) a spacer and (3) a carbohydrate unit. Additionally two different types of mixed structures have been synthesized: (a) single-chained carbosilane-siloxane surfactants and (b) double-chained combinations of carbo- silanes, silanes and siloxanes. The wetting behaviour of the key intermediates, the allyl glycidyl derivatives, has been investigated by static surface tension (γlv, σ) and wetting tension (γsv-γsl, α) measurements on a non-polar perfluorinated surface (FEP® plate). The contact angles obtained for these pure liquids are not a linear function of the surface tension but depend on the polarity of the substructures. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 10 (1996), S. 437-450 
    ISSN: 0268-2605
    Keywords: siloxanes ; surfactant ; carbohydrate ; amino ; regioselective ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Branched siloxanyl-modified carbohydrate surfactants have been synthesized by coupling mono-, di- and poly-functional siloxanes to carbohydrate units either via a branched spacer or by attaching a separate modifying element to a straight-chained structure. Hydrophilic as well as extremely hydrophobic elements have been incorporated successfully. Siloxanyl-modified carbohydrates bearing a secondary amino function were alkylated in regioselective reactions by different epoxides ranging from glycidol- to siloxanyl-modified allyl glycidyl ether derivatives. Alternatively, carbohydrate-modified piperazinyl structures yielded cyclic subunits after alkylation. Structures bearing two identical hydrophilic groups are accessible by alkylation of carbohydrate-modified bisamides. The derivatives synthesized were characterized by means of GC, NMR and elemental analysis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Applied Organometallic Chemistry 11 (1997), S. 523-538 
    ISSN: 0268-2605
    Keywords: silicon-modified ; carbohydrate ; surfactant ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ionic siloxanyl-modified carbohydrate surfactants have been synthesized by alkylation/esterification of precursors containing tertiary amino functions. Depending on the reaction strategy, the siloxanyl moiety is part of the alkylating agent or the substrate. Polyhydroxylated tertiary amines can be quaternized by siloxanyl-modified chloroacetic acid esters or epoxysiloxanes in the presence of glacial acetic acid. The esterification of tertiary amines bearing carbohydrate and siloxanyl subunits by cyclic acid anhydrides yields, after neutralization, carboxylate salts. The reaction of hydroxyl groups and sulfamic acid leads to sulfates. The new substances were characterized by means of 13C NMR spectroscopy, gas chromatography, elemental analysis and their solubility profile. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0268-2605
    Keywords: siloxanyl-modified ; carbohydrate ; surfactant ; wetting behaviour ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The siloxanyl-modified carbohydrate surfactants investigated consist of the four structural elements: (1) siloxanyl moiety; (2) spacer; (3) carbohydrate unit; and (4) modifying element. By static surface tension (γsν  -  γsβ α) measurements the contact angles of the aqueous surfactant solutions above the critical micelle formation concentration (cmc) on nonpolar perfluorinated surfaces (FEP® plate) were determined. Although the siloxanyl units were found to have a high capacity to level out the interfacial properties, both surface tension and wetting tension react independently to defined changes in the chemical structure of the surfactant molecules. The results of spreading experiments on polyproylene show good correlation with the dependences found by wetting meaurements. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0268-2605
    Keywords: siloxane ; surface tension ; control angle ; interfacial tension ; wetting tension ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The surface tensions, wetting tensions, contact angles and solid/liquid interfacial tensions of defined siloxanes as well as those of analogous carbosilanes, polysilanes and neopentyl substituted silanes were determined. The wetting experiments were carried out on a glass plate coated with perfluoroalkyl methacrylate (FC 722®). The siloxanes possess the lowest surface tensions. Due to the presence of oxygen atoms in the siloxane backbone, a donor-acceptor portion (γ+/-lv) of the surface tension of about 1-2 mN/m was determined. The solid/liquid interfacial tension also contains a donor-acceptor portion (γ+/-sl). Its value is almost identical to that of γ+/-lv. The γ+/-sl differences between individual molecules of the same surface tension are responsible for contact angle differences of up to 4°. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Linear poly(dimethyl siloxanes) bearing vinyl groups can be converted to crosslinked products by photoinitiated formation of radicals. In chloroform solution the quantum yield indicated by the decrease in double bonds (ΦP) assumes values of 0.9 to 2.5, depending on the type of initiator. It decreases with rising silicon concentration. A ΦP-value of 0.01can be extrapolated for solvent free systems. Under these conditions network formation is particularly efficient with benzoin derivatives. As the content of vinyl groups increases the network density also rises. As is demonstrated by IR spectroscopic studies on benzoin derivatives as initiators and by characterization of the networks built up this way, network formation is almost exclusively due to the vinyl groups.
    Notes: Lineare vinylgruppenhaltige Poly(dimethylsiloxane) können durch eine photoinitiierte Radikalbildung in vernetzte Proben überführt werden. In CHCI3-Lösungen erreichen die Quantenausbeuten der Doppelbindungsabnahme (Φp) Werte von 0,9 bis 2,5 Sie hängen vom Initiatortyp ab und sinken bei Erhöhung der Siliconkonzentration. Für lösungsmittelfreie Systeme kann ein ΦP-Wert von 0,01 extrapoliert werden. Unter solchen Bedingungen erfolgt die Netzwerkbildung besonders effektiv mit Benzoinderivaten. Mit steigendem Vinylgruppengehalt der Silicone erhöht sich die Netzwerkdichte. IR-spektroskopische Untersuchungen mit Benzoinderivaten als Initiator und die Charakterisierung der entstandenen Netzwerke zeigen, daß die Netzwerkbildung fast ausschließlich über die Vinylgruppen abläuft.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0268-2605
    Keywords: carbohydrate-modified phenylsiloxane ; surfactants ; wetting behaviour ; superspreading ; Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dynamic wetting behaviour on a perfluorinated, low-energy solid has been investigated for a carbohydrate-modified phenylsiloxane surfactant. The surfactant concentration, the rate of interface generation and the [solid/liquid interface area] : [liquid/vapour interface area] ratio were varied systematically. Dynamic data for the liquid/vapour (γlv) and solid/liquid (γsl) interfacial tension as well as their Lifshitz-van der Waals and donor-acceptor contributions were determined under strictly controlled conditions. Since γsl reacts sensitively to variations of the surfactant concentration and the rate of interface generation, the covering of the liquid/non-polar solid interface is assumed to be a spreading limiting factor. The corresponding γlv values remain constant and close to those obtained under equilibrium conditions. Copyright © 1998 John Wiley & Sons, Ltd.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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