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  • 1
    Electronic Resource
    Electronic Resource
    Probability model treatment of regio- and stereo-irregular polymersHercules Research Center Contribution Number 2204. (1994)
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 979-1004 
    Details
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A general analytical approach is devised to treat the NMR data of stereoirregular and regioirregular homopolymers. The methodology is based on the four-component copolymerization model, treating normal and inverted monomer and the levo and dextro configurations as “comonomers”. In this way, the effects of monomer inversion and tacticity can be separately deduced. The analytical approach has been computerized. From the conditional probabilities, information on propagation mechanism (chain-end or catalytic-site control) can be obtained. The model has been used to analyze the NMR data of poly(propylene) samples made with titanium, vanadium and group IV metallocene catalysts. Comparisons have been made between model parameters and polymer microstructure.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mats.1994.040030605
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  • 2
    Electronic Resource
    Electronic Resource
    Tacticity of poly(N-vinyl pyrrolidone) (1981)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 19 (1981), S. 29-31 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1981.130190106
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  • 3
    Electronic Resource
    Electronic Resource
    Theory of reverse osmosis and some other membrane permeation operations (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 83-95 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The general permeation equations for various transport operations using membranes were correlated according to the solution-diffusion theory. It was shown that for some important conditions, the permeation properties for reverse osmosis can be generated from those of pervaporation. The use of reverse osmosis with pressure smaller than 2000 psi is calculated to be of limited use for the purification of water with small amounts of organic compounds.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190107
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  • 4
    Electronic Resource
    Electronic Resource
    13C-NMR determination of the tacticity of polyepichlorohydrinHercules Research Center Contribution Number 1934. (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 34 (1987), S. 909-912 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The microstructure of polyepichlorohydrin was directly studied by high-field 13C-NMR. Spectral features were found that correspond to different tacticities. By using curve deconvolution techniques, the different tacticities were assigned and quantified.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070340303
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  • 5
    Electronic Resource
    Electronic Resource
    Stereochemistry of vinyl polymers and NMR characterizationHercules Research Center Contribution No. 1936. (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 229-241 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The configuration of vinyl polymers has been conventionally described by either Bovey's or Price's formalism. In this work, the relationships between these two formalisms are derived, and their relevance to polymerization mechanisms is delineated. Experimental data for nuclear magnetic resonance (NMR) pertaining to either chain-end control or catalytic-site control are tested using the computerized “analytical approach.” Suitable polymeric systems are illustrated.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360118
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  • 6
    Electronic Resource
    Electronic Resource
    Free-radical polymerization of methyl methacrylate initiated by thiol alone (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 45 (1992), S. 579-582 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Three different alkyl thiols, i.e., n-propylthiol, isopropylthiol, and 2-methyl-2-undecanethio1, were proved efficient to initiate the polymerization of methyl methacrylate at 40°C. The initial polymerization rate, Rp, increases with increasing thiol concentration but cannot be described by a single-power law. However, Rp is proportional to 1.3th power of the monomer concentration, indicating the participation of monomer in the initiation reaction. With increase of the polarity of solvents, Rp decreases, demonstrating the polar property of the initiating intermediate. The apparent activation energy of overall polymerization was calculated to be 9.3 kcal/mol. Molecular weight measurements indicated the twofold function of the thiol as both an initiator and a regulator.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1992.070450403
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  • 7
    Electronic Resource
    Electronic Resource
    Synthetic membranes containing schardinger cyclodextrin additives (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 489-497 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The permeation characteristics of the isomers of such aromatics as dichlorobenzenes, nitrochlorobenzenes, xylenes, etc., through a Methocel HG membrane containing various amounts of Schardinger α-cyclodextrin and β-cyclodextrin additives were measured in liquid/liquid dialysis and pervaporation experiments. The results showed that the cyclodextrins are able to selectively mediate molecular transport through the Methocel HG membranes. In general, increased membrane selectivity and a decrease in permeation rates were observed. Permeation rates for some aromatic compounds were decreased several hundred times with only 25% amounts of additive cyclodextrins in the Methocel HG membranes. Concentration electrical potential and bi-ionic electrical potential in membranes containing the Schardinger cyclodextrin have been measured and also show that the cyclodextrins are able to induce ion transport selectively through nonionic membranes. Dynamic mechanical properties of Methocel HG membranes containing cyclodextrins suggest these additives to be antiplasticizing agents. A mechanism for the modification of the intrinsic membrane permeation properties by cyclodextrin additive involving antiplasticizing action by the additives plus induced tortuous diffusion, where the latter is a result of specific interactions between the cyclodextrin additive and the permeating molecules, is proposed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070260209
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  • 8
    Electronic Resource
    Electronic Resource
    13C-NMR sequence determination for multicomponent polymer mixturesHercules Research Center Contribution Number 1953. (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 35 (1988), S. 1639-1650 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A general treatment is developed for the 13C-NMR analysis of polymers which contain several components. Reaction probability models and computer optimization techniques are used to resolve the NMR spectral data into separate components. The use of generalized multistate statistical models is introduced and is found to be very suitable for such systems. The computations are simplified by means of computer programs. The need for, and the relevance of, this approach are illustrated by the tacticity problems in polybutylene and polypropylene where two-state and three-state models are used, and copolymer triad sequence analysis for several olefin and acrylic copolymers where two-state models are needed. Three copolymer examples are given: propylene/butylene, ethylene/propylene, and acrylamide/acrylate.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070350619
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  • 9
    Electronic Resource
    Electronic Resource
    Time lag and permeation rate in liquid/liquid dialysis (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 3087-3091 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Time lag and permeation rate in liquid/liquid dialysis in general are found different from those in pervaporation. Theoretical treatments of time lag in liquid/liquid dialysis indicate that time lag, in certain cases, may be correlated to the “relaxation time” of the membrane, defined as the time required for the membrane to relax, or as the change of the permeation flux of diffusable species from initial flux to steady state due to the long time required for the dialysis solvent to reach steady state in the membrane. The permeation of dichlorobenzene in a Teflon-FEP membrane for both the operations of liquid/liquid dialysis and pervaporation was measured as an example. It was found that the time lag in liquid/liquid dialysis is much longer than that calculated from a diffusion constant calculated from pervaporation. Permeation rate and activation energy are also different in both operations.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070191113
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  • 10
    Electronic Resource
    Electronic Resource
    Bi-ionic potentials in anion exchange membranes (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 21 (1977), S. 851-853 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1977.070210326
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