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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 25 (1992), S. 3009-3014 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 170 (1952), S. 1026-1027 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] During the polymerization of a vinyl monomer, branching occurs owing to a growing radical attacking a dead polymer molecule, abstracting a hydrogen atom and forming a free valency in the polymer chain; growth of a side-chain can begin at this point. It has been demonstrated that if a monomer is ...
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Rheologica acta 27 (1988), S. 69-75 
    ISSN: 1435-1528
    Keywords: Polyethyleneblend ; shrinkage effect ; compatibility ; elongationalflow ; minifibre
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract An experimental study of the shrinkage effect in low density-high density polyethylene blends, high density-high density polyethylene blends and low density polyethylene-ethylene vinyl acetate copolymer blends is presented. Viscosity measurements are also included. The strain recovery is analysed as the addition of the interfacial tension effect and the elastic recoverable strain. The results are compared with those obtained for other polyolefin blends observing that in the case of compatible systems as low density-high density polyethylene and high density-high density polyethylene blends the strain recovery and the viscosity follow approximately the additive rule. In the case of more incompatible systems like polyethylene-ethylene vinyl acetate copolymer, polyethylene-polypropylene and others very large recoveries were observed. The formation of minifibres of the dispersed phase during the preparation of the samples is suggested as responsible for the obtained results.
    Type of Medium: Electronic Resource
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  • 4
    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 Excess volumes at 60°C for concentrated mixtures of poly (ethylene oxide) and toluene have been determined.The volume change of mixing is negative, amounting to −0.59% of the total volume at the segment fraction φ2 = 0.5. This result has been used in adjusting the energy parameter X12 = 1.8 cal cm−3, from which theoretical values of the residual chemical potential parameter X, partial molar enthalpies and entropies at different concentrations can be evaluated through the Flory-Prigogine-Patterson theory. Solvent activities for moderately concentrated solutions have been measured by vapour pressure osmometry at 42°and 70°C. Inverse gas chromatography was also used in order to obtain the X value at φ2 = 1. The reduced partial molar excess enthalpy K was calculated from the experimental viscosity-temperature coefficient. Experimental and theoretical values have been compared.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 184 (1991), S. 19-26 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Einfluß der Cerammoniumnitrat(CAN)-Konzentration auf die Pfropfcopolymerisation von 4-Vinylpyridin (4-VP) auf Baumwolle wurde mit drei Versuchsreihen untersucht. In der ersten Reihe wurde die CAN-Konzentration zwischen 0,05 und 100 mmol/l variiert, parallel dazu die Nitratkonzentration. In den beiden anderen Reihen wurde die CAN-Konzentration variiert, die Nitratkonzentration aber durch Zugabe von Natriumnitrat konstant bei 1,09 bzw. 1,59 mol/l gehalten. Pfropfausbeute und Gesamtumsatz durchlaufen bei Änderung der CAN-Konzentration ein Maximum. Das Maximum der Pfropfausbeute liegt bei konstanter Nitratkonzentration bei niedrigerer CAN-Konzentration als bei veränderlicher Nitratkonzentration. Bei allen drei Versuchsreihen wurde jedoch annähernd die gleiche Pfropfausbeute erreicht. Der Cerionenverbrauch nimmt mit steigender Initiatorkonzentration und steigender Nitratkonzentration zu.
    Notes: For the study of the effect of ceric ammonium nitrate (CAN) initial concentration on the graft copolymerization of 4-vinylpyridine (4-VP) onto cotton three series of experiments were carried out. In the first one the CAN concentration was varied from 0.5 to 100 mmol/l and so, parallely, the total nitrate ion concentration. In the other two series the CAN initial concentration was varied, but keeping the total nitrate ion concentration constant at 1.09 and 1.59 M, respectively, by sodium nitrate addition. Increasing the ceric salt concentration the graft yield and total conversion reached a maximum. When the nitrate ion concentration was kept constant the maximum graft yield value was achieved at CAN concentrations lower than when it was varied. However, for all the three series of experiments the maximum graft yield value was nearly the same. The ceric ion consumption increased with increasing initiator concentration. The higher the total nitrate ion concentration, the higher was the ceric ion consumption.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The purpose of this study has been to study the flow behavior of several polystyrene samples ranging in molecular weight between 1 × 105 and 2 × 101 in several solvents. Intrinsic viscosities corrected for shear effects have been obtained according to several treatments already described in the literature. The results obtained show considerable divergences. The flow behavior of the samples was then studied from a rheological point of view; it is shown that the solutions are more and more Newtonian, the nearer they approach to zero shear stress. Interpretations of the viscosity plots are given. As a consequence, extrapolation of the viscosity curves obtained at very low shear stresses with the use of a special capillary viscometef to zero shear is considered to be the most convenient way of obtaining intrinsic viscosities corrected for shear; such a method is described. The results, in some cases, may be up to 60%, larger than the highest value obtained by the classical methods. The influence of solvent and molecular weight on this shear effect is also considered, and the whole situation is considered, taking into account the possible “structure” of the solutions and the nature of the polymers.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 1327-1333 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Grafted PMMA was isolated by the acid hydrolysis method. Weight-average and number-average molecular weights were determined by gel permeation chromatography. The number-average molecular weight of the grafted chains was about 475,000 for amylopectin and 403,000 for amylose. The number of grafted chains (mmol) ranged from 2.4 × 10-3 to 4.6 × 10-3 for amylopectin graft copolymers and from 2.9 × 10-3 to 6.8 × 10-3 for those of amylose. These results were related to others obtained from ceric ion consumption studies. The values suggest that amylopectin, because of its complex structure, favors a higher consumption of ceric ion in homopolymerization reactions and inhibits the initiation reactions of the copolymerization.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 20 (1982), S. 181-185 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2729-2732 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 21 (1983), S. 2573-2580 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A study was made of the ceric-ammonium-nitrate-initiated graft polymerization of methyl methacrylate (MMA) onto a lineal fraction of starch (amylose). Grafting yields were determined by extraction with appropriate solvents: 1,2-dichloroethane for homo-PMM, and 0.5N NaOH for ungrafted amylose. Percent grafting was calculated by acid hydrolysis with 1N HCl. Molecular weights of PMMA side chains were determined by gel permeation-chromatography. Grafting efficiencies ranged from 72 to 83%, grafting, from 190 to 271%, and frequency of attachment of side chains, from 900-1250 glucose units per chain. The results observed are discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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