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  • Physics  (907)
  • 1970-1974  (545)
  • 1965-1969  (362)
  • 1950-1954
  • 1935-1939
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  • 1
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 6 (1968), S. 871-883 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The following measurements were carried out on the melts of two samples of polypropylene, one with a narrow and one with a broad molecular weight distribution: viscosity in steady shear flow, dynamic storage and loss moduli, total normal thrust in cone-and-plate apparatus, and flow birefringence. The validity of various theoretical interrelations between the measured quantities is checked. The influence of molecular weight distribution is qualitatively discussed.
    Additional Material: 7 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 5 (1967), S. 1305-1308 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 191-192 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 4 (1966), S. 401-414 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(vinyl fluoride) polymers prepared at different polymerization temperatures have been examined in the melt, oriented, and solid state by infrared spectroscopy. Bands arising from the head-to-tail and head-to-head-tail-to-tail portions of the polymer have been isolated and assigned. The head-to-head-tail-to-tail portion of the polymer crystallizes in the head-to-tail unit cell except for a portion of the 1,2-difluorethylene units which apparently have the gauche (out-of-plane) structure. The head-to-tail portion of the polymer is nearly atactic, but is somewhat rich in syndiotactic chain structure. Bands arising from local syndiotactic order are observed.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 10 (1972), S. 2125-2134 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The validity of Silberberg's hypothesis concerning the conformation of branched polypeptides was tested by studies on solutions and on monolayers. The poly(α-amino acids) investigated consisted of poly-L-lysine backbones with side chains of poly(gamma;-benzyl L-gutamate) and poly(β-benzyl L-aspartate). In solution, the conformation was studied in the mixed solvent chloroform-dichloroacetic acid. Optical rotatory dispersion measurements demonstrated the existence of a helix-coil transition which is a function of the length of the side chain. A significant “transition curve” appeared between 9 and 15 residues. From the results, it may be assumed that the poly-L-lysine backbone is extended in a coiled conformation and the side chains are coiled or helical, depending on the number of glutamate residues. At the air-water interface, a discontinuity in the surface-pressure curve appears between 9 and 15 residues per side chain. The similarity with the results obtained in solution appears significant; however, this has to be confirmed with methods more specific for structural modifications.
    Additional Material: 6 Ill.
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  • 6
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The bulk polymerization of acrylonitrile (AN) initiated by copper (II) nitrate, Cu(II), in the absence of light has been studied. The rate of the AN polymerization may be expressed in the Cu(II) concentration range from 5 × 10-4 to 1 × 10-1 mole 1.-1 by the equation, Rp = k5[Cu(II)]0.68, where k5 = KAN[AN]/(1 + KAN[AN]). From the spectrophotometric measurements the values of 0.70 l./mole and 0.08 l, mole were obtained for the equilibrium constant at 20 and 60°C, respectively, KAN = [C]/[AN]-[Cu(II)], corresponding to the formation of the complex C from acrylonitrile and copper (II) nitrate. An addition of triphenylphosphine (C6H5)3P into the polymerization system reduces Rp, and no polymerization takes place at all provided [(C6H5)3P]/[Cu-(II)] ≧ 5. The retardation effect of (C6H5)3P on the polymerization of AN initiated by Cu(II) is attributed to a competitive reaction of Cu(II) with (C6H5)3P in which Cu(II) is reduced and the product of this reduction CuNO3·2(C6H5)3P is inactive with respect to the polymerization of AN.
    Additional Material: 7 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 2031-2043 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Farol-Weissenberg rheogoniometer has been used to follow molecular weight changes during the degradation of certain poly-α-esters in the melt state. By observing the change in melt viscosity at low shear rates it had been shown that the decomposition of the poly(isopropylidene carboxylate) is substantially first-order with respect to the molecular weight of the residual polymer. The derived kinetic parameters are in good agreement with those previously obtained by other techniques. This provides a substantial piece of supporting evidence for the view that degradation takes place predominantly by intramolecular ester interchange involving the formation of 1,1,4,4,-tetramethylglycollide. The introduction of β-chlorine atoms into the polymer structure leads to a more complex degradation pattern. Thus the presence of a single β chlorine atom per repeat unit, as in poly(3-chloro-2-methyl-2-hydroxypropionic acid) leads to a substantially similar dependence on molecular weight with the added complication of progressive crosslinking which becomes more apparent in later stages of the reaction. This crosslinking reaction plays an increasingly important part as the extent of chlorination of the polymer is increased. In addition, the presence of chlorine leads to an increased sensitivity of the degradation reaction to the presence of oxygen.
    Additional Material: 6 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 11 (1973), S. 2991-2997 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Poly-3-methyl-1-butene has been synthesized by Et2AlCl/tBuCl initiator at -130°C. A cast film of this material gave three well defined crystalline phases, α, β, and γ, characterized by infrared spectroscopy. The γ polymorph could not be obtained independently of the other two. Synthesis and/or manipulative procedures that would consistently give only one of the polymorphs are still unavailable. Evidently, the three crystalline phases have very similar lattice energies, and the subtle factors that determine the ultimate nature of the crystal lattice are not yet understood.
    Additional Material: 4 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 5 (1967), S. 2067-2077 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The meso- and d,l-diastereomers of o-bis(epoxyethyl)benzene have been synthesized and identified. The diastereomers were polymerized by a variety of catalysts to give a polymer which has mainly isochroman recurring units as a result of a cyclopolymerization mechanism. Some features of the polymerization with the triisobutylaluminum catalyst system have been studied. The rates of polymerization of the monomers and the transition temperatures of the resulting polymers have been determined. The results are explained on the basis of a controlled intramolecular propagation and a stereospecific polymerization.
    Additional Material: 4 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-1: Polymer Chemistry 8 (1970), S. 683-692 
    ISSN: 0449-296X
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel preparation of polyamide-imides from diphenylmethane diisocyanate and trimellitic anhydride in N-methylpyrrolidone is described. Partial substitution of trimellitic anhydride with either maleopimaric acid, terephthalic acid, or by various di-anhydrides permitted a correlation of structure with solution stability and thermal properties. Heat resistance improved with increasing imide content of the polyamide-imide. Almost all solutions advanced in viscosity on storage at room temperature. The least stable solutions were those that deviated the most from 50-50 amide-imide. However, the viscosity changes depended somewhat on the type of modifying ingredient. For example, polyamide-imides modified by substitution of 10% PMDA (pyromellitic anhydride) or BPDA (benzophenone tetracarboxylic acid dianhydride) were less stable than those modified with 10% (cyclopentanetetracarboxylic acid dianhydride) CPDA or THFDA (tetrahydrofuran-2,3,4,5-tetracarboxylic acid dianhydride). The use of excess reagent and of monofunctional chain stopper was investigated as a means of controlling solution stability.
    Additional Material: 5 Ill.
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