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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 3157-3166 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Light-scattering data from tamarind seed polysaccharide (TSP) very often result in different molar masses and dimensions. This effect is due to a strong tendency to self-association of the polysaccharide. The relation between particle masses and radii of gyration indicates worm-like chain behaviour of TSP at fairly low particle masses. The solution properties of TSP in this regime may conveniently be described by the model of bundle-shaped lateral aggregates of single polymer chains, whereas the aggregates seem to attain more spherical shape at higher degree of aggregation. It is shown that the relation of thermodynamic and hydrodynamic behaviour of TSP is different from that of Gaussian coils and is rather that of polymers which are known to be of high chain stiffness.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 1371-1376 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The technique of transmission electron microscopy (TEM) in combination with electron spectroscopic imaging and digitized image processing was used for determination of particle size and size distribution of a starshaped polystyrene sample. The results were compared with measurements of the translational diffusion coefficient Dz from dynamic light-scattering method. The particle diameter dEM achieved by TEM-measurements is in good agreement with the effective hydrodynamic radius Rh from the Stokes-Einstein relationship.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 71 (1964), S. 47-61 
    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: Poly-p-chlorostyrene was metallated by sodium-naphthalene in tetrahydrofuran yielding poly-p-sodiumstyrene. The reaction conditions were studied in detail under which the reaction products are soluble. By protonolysis the metallated polymers are converted to polystyrene showing no degradation but a decrease of intrinsic viscosity, which is discussed. Light scattering measurements give a relation between intrinsic viscosity and average molecular weight of poly-p-chlorostyrene.
    Notes: Poly-p-chlorstyrol wurde mit Natrium-Naphthalin in Tetrahydrofuran zu Poly-p-natriumstyrol metalliert. Die Reaktion sbedingungen, unter denen lösliche Produkte entstehen, wurden im einzelnen untersucht. Durch Protonolyse werden die metallierten Polymeren in Polystyrole überführt. Diese zeigen keinen Abbau, jedoch eine Abnahme des STAUDINGERindex, die diskutiert wird. Streulichtmessungen an Poly-p-chlorstyrol führen zu einer Beziehung zwischen STAUDINGERindex und mittlerem Molgewicht.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 1403-1426 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyfunctional chain transfer reagents applied in free radical polymerization have two effects on the polymer molecular weight. As in the case of monofunctional regulators the chain length is reduced; the polyfunctionality of the transfer reagents causes, however, branching and thus an increase in molecular weight. A general theory is developed on the basis of Cascade Theory to describe the polymer structure in dependence on the monomer conversion. The theory takes advantage of the graph theoretical concept of digraphs by which the directed chain reaction can be properly represented. Analytic equations are derived for the weight average molecular weight Mw, z-average mean square radius of gyration 〈S2〉z and the average particle scattering factor Pz(μ). Furthermore, a simple equation is given for the condition of gelation. Special concern is given to the formation of fractions of branched and linear polymers during the polymerization process. The derived equations are discussed in terms of kinetic constants known for polystyrene. Gelation is shown to be possible for a chain transfer constant of Ctr = 22 if the number of functional groups per transfer molecule exceeds at least a value of 7.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 1427-1437 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of neopentanetetrayl tetrakis(2-mercaptoacetate) on the molecular weight of polystyrene in free radical polymerization was studied. Polymerization experiments were carried out at three different concentrations of the tetrafunctional transfer reagent and were followed to monomer conversions up to β = 25%. For comparison, runs of polymerization were made without added transfer reagent and with a monofunctional 2-mercaptoacetate, respectively. An apparent extent of branching was calculated from the molecular weights Mw obtained with the tetrafunctional and the monofunctional transfer reagent at fixed monomer conversion β and fixed concentration of reagent groups. This apparent extent of branching passes through a maximum at very small β and approaches the value 1 for large β. The decrease in the extent of branching is shown to be caused by the increasing fraction of linear polystyrene as the transfer reagent becomes exhausted.The data observed were compared with curves calculated from Cascade Theory with the known kinetic constants for polystyrene. A very good agreement between theory and experiment is observed at medium concentration of transfer groups. At smaller concentrations the increase in Mw is less than that predicted, and at large concentrations the increase in Mw is stronger than expected by theory. The deviations are attributed to negative and positive substitution effects.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 185 (1984), S. 2543-2552 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Critically branched polyurethanes of varying molecular weight were prepared from poly(oxypropylene)triol and methylenedi-p-phenylene diisocyanate with and without solvent. The static/dynamic light scattering from DMF solutions of these samples was measured. The results were discussed in terms of the classical (Flory-Stockmayer, FS) and percolation theory of gelation; the bulk-polymerized sample obeyed the FS process, whereas the solution-polymerized samples were better described by the percolation process.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 191 (1990), S. 169-184 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(vinyllactams) form a class of non-ionic water-soluble polymers from which only poly-(1-vinyl-2-pyrrolidone) (PVP) is well known and has been investigated extensively. The homologues poly(1-vinyl-2-piperidone) (1, poly[1-(2-oxo-1-piperidyl)ethylene]) and poly(N-vinylcaprolactam) (2, poly[1-(2-oxoperhydroazepin-1-yl)ethylene]) which are still soluble in water at room temperature have not yet been studied in aqueous solution. In this work the synthesis of these two polymers by radical polymerization in solution and the investigation of the dilute aqueous solution properties of these polymers by static and dynamic light scattering measurements are presented. Special attention is paid to the influence of the increasing hydrophobicity of these polymers on coil dimensions and structures in aqueous solution.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 173 (1973), S. 235-239 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 1821-1835 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The scattering behaviour and the critical conditions where gelation takes place have been calculated for polycondensates formed under constraints. The general model includes fully random and stringently restricted reactions as limiting cases. Also polycondensates of glycerine-type monomers are included as special cases. The particle scattering factors of the f-functional random polycondensates differ remarkably from those polycondensates formed under strict constraints. The former show a Kratky plot of a simple curve, independent of the magnitude of the molecular weight and the number of functional groups, and the curve approaches a constant asymptote of u2·Pz(u)=3, the latter exhibits a maximum at u2=6 which becomes more pronounced with increasing molecular weight, (u2 = 〈S2〉zh2, with h, the value of the scattering vector). The scattering curves of the polycondensates formed under weak constraints show at low molecular weights the same behaviour as those formed under stringent constraints, but approach the behaviour of random polycondensates at large molecular weights. The scattering curves of the glycerine-type polycondensates show no deviations in shape from random polycondensates.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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