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  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 571-573 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 557-566 
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase behavior and scattering properties of crosslinked charged polymer blends in solution are examined. De Gennes' analogy between the effects of crosslinks in a network and electrostatic charges in a dielectric medium on the scattering properties and the phase behavior of crosslinked polymer blends is used. This analogy is extended to include the effects of screening in order to improve its agreement with the experimental data in the small q range. The excluded volume interactions are explicitely introduced through the blob model. The enhancement of compatibility of the mixture and the increase of its rigidity constant are evaluated in certain cases. The limit of neutral polymers is discussed because it corresponds to the case of charged mixtures in the presence of excess salt. The kinetics of the microphase separation transition is briefly discussed. A dynamical model including the long range hydrodynamic interaction is presented. The relaxation frequency of the stable modes and the growth rate of unstable ones are also considered.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 1005-1031 
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Computer simulations have been used to study the application of statistical model discrimination techniques to the modelling of copolymerization reactions based on triad fraction data. Since there are six triad fraction measurements, the problems of parameter estimation and model discrimination become multivariate problems. The multivariate forms of three model discrimination methods (exact entropy, Hsiang and Reilly, and Buzzi-Ferraris et al.) are presented. Programs have been developed to simulate the application of these techniques to the systems styrene-acrylonitrile, styrene-methyl methacrylate and styrene-butyl acrylate. The simulation programs are explained, including the method used to simulate triad fraction data. Evidence is presented that the simulation programs are capable of duplicating the type of measurements that would be obtained in the laboratory. The simulation results show that model discrimination methods are able to accurately and reliably discriminate between the terminal and penultimate models. The use of simulated model discrimination methods leads to reliable discrimination in fewer experiments than have been used in past work. Also, model discrimination methods are able to detect smaller penultimate effects than those found by Hill et al. for styrene-acrylonitrile. In addition, the results show that the use of four of the six triad fractions, versus one copolymer composition measurement, should lead to more precise reactivity ratio estimates and an increased ability to discriminate between the terminal and penultimate models. Our work suggests that use of model discrimination methods will indeed lead to improvements in the modelling of copolymerization reactions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 543-555 
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several models and methods for stiff polymer chains are discussed. The basic idea is to develop approximate solutions to the problem of the presistence length of stiff polymers. It turns out that the persistence length can be regarded as a measure for the quality of approximations. Mean-field methods for field theoretical calculations of the persistence length show similarities of 1/d expansions in statistical physics (d being the space dimension) and saddle point approximations become reliable in various limits. Gaussian approximations become  -  as well known for the Ising model  -  simple extensions of random walks as trivial renormalisations of the Wiener-Edwards model for bosonic strings.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 73-77 
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mode-mode coupling approximation (MMCA) is used to describe the behavior of the reduced viscosity of weakly charged polyelectrolyte solutions in the presence of screening of hydrodynamic interactions. This effect is introduced through a dynamic correlation length ζH in the Oseen tensor description. The results show that as ζH goes from zero (Rouse model) to infinity (Zimm model), the general qualitative behavior of ηr as function of the polyelectrolyte concentration Cp does not change but its value decreases significantly with a slight shift in the peak position toward higher Cp values.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Theory and Simulations 3 (1994), S. 271-293 
    ISSN: 1022-1344
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper discusses the effect of heterogeneities in crosslink density on static properties, such as the mechanical stress-strain relation (free energy) and scattering effects as occur in small-angle neutron experiments. The second part of the paper is devoted to the segmental dynamics and the long-time relaxation of polymer networks. It is shown that the heterogeneities slow down the relaxation at long times.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 43 (1991), S. 145-155 
    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 use of plasma deposition to introduce sulfonate groups to the surface of a polyurethane was attempted. In previous work, the bulk incorporation of sulfonate groups was found to improve the blood contacting properties of the base polyurethane but physical properties in the hydrated state were adversely affected. Plasma deposition schemes involving ammonia and sulfur dioxide were utilized in an attempt to incorporate sulfonate groups. Surface characterization by X-ray photoelectron spectroscopy (XPS) and contact angle measurements was used to follow polymer surface rearrangement dynamics and to address the issue of plasma chemistry specificity. Concerns of reaction specificity were alleviated by using the plasma as a pretreatment which is followed by a chemical surface derivatization.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Theory and Simulations 1 (1992), S. 25-30 
    ISSN: 1018-5054
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: We present new results on the behaviour of single chains in homo-and copolymer blends which are beyond the rendom phase approximation (RPA). The radius of gyration of a chain in the blend was found to depend strongly on the interactions as well as the effective diffusion constant of a single chain in the blend or copolymer melt. Note that these results cannot be obtained in the original formulation of the RPA. They are based on the effective Hamiltonian of the chain in the medium. In the equation found for the self diffusion constant of a single chain, Ds, the second term is directly the value of the effective potential at zero wave vector. Thus the measurement of Ds would detect the screened potential at q = 0. Experimental verification of these results is in progress.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Theory and Simulations 1 (1992), S. 3-23 
    ISSN: 1018-5054
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The static scattering properties of weakly charged copolymers in solution are investigated. The cases of symmetrical and nonsymmetrical diblocks are considered and various structure factors calculated. The electrostatic interaction is introduced via a combination of the random-phase approximation and the Debye-Hückel approximation. Several cases of charge distributions are considered. In particular, diblock copolymers made of neutral and charged monomers and oppositely charged monomers are considered. All the cases deal with systems in the homogeneous disordered phase where no mesophase structures or micelle formations can be observed.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Basel : Wiley-Blackwell
    Die Makromolekulare Chemie, Theory and Simulations 2 (1993), S. 349-360 
    ISSN: 1018-5054
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The time evolution of the static structure factor following a sudden temperature jump ΔT is investigated in the case of a symmetric mixture of two polymers and a solvent in the optical theta conditions. The two reverse processes corresponding to ΔT 〉 0 and ΔT 〈 0 are considered, and the kinetics of approach towards the final states are investigated both in the Rouse limit and in the presence of hydrodynamic interactions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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