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  • Polymer and Materials Science  (20)
  • 1990-1994  (13)
  • 1965-1969  (7)
  • 1935-1939
  • 1930-1934
  • 1
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: C-terminal analogues of neuropeptide Y (NPY) of small molecular size have been synthesized. The influence of chain length, single or multiple amino acid substitution, and segment substitutions on receptor binding, pre- and postsynaptic biological activity, and conformational properties have been investigated. Receptor binding and in vivo assays revealed biological activity for NPY Ac-25-36 that increased with increasing α-helicity. In attempts to stabilize the α-helical content, three independent types of modified NPY Ac-25-36 analogues were synthesized. Strong agonistic activities could be detected in a series of discontinuous analogues, which are constructs of N-terminal parts linked via different spacer molecules to C-terminal segments. One of the most active molecules was NPY 1-4-Aca-25-36 (Aca, ε-aminocaproic acid). For the first time conformational properties of a series of small NPY analogues have been investigated by CD, and correlated with biological activity and receptor binding. A C-terminal dodecapeptide segment of NPY with an amount of 50% substitution to the native C-terminal sequence of NPY was found to exhibit significant receptor binding.
    Additional Material: 6 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. 2725-2739 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The galvanostatic electropolymerization of thiophene (1), 3-methylthiophene (2) and 2,2′-bithiophene (3) in acetonitrile, containing 0,002 to 20 mol/L water, was studied in detail. The current efficiency γ for the polymer film formation decreased rapidly for 1, but much slower for 2 and 3 with increasing water concentration cH2O. For cH2O = 0,1 mol/L, γ was found to be 10, 82 and 95% for 1-3. It was possible to describe the experimental γ vs. cH2O plots quantitatively by a model where the electrogenerated radical cations (rc) of the thiophene (derivative) are consumed by two competing second-order follow up reactions, the nucleophilic attack of the rc by water (i) and the rate-determining dimerization of two rc's (ii). Their rates are given by: (i) v1 = k1 crc cH2O and (ii) v2 = k2 c2rc. The side reaction (i) leads to soluble products, while reaction (ii) contributes to the polymer film growth. The ratio k1/k2 was found to be 3 · 10-7, 2 · 10-8 and 4 · 10-9 for 1, 2 and 3, respectively, and this shows that the electropolymerization of 2,2′-bithiophene is by a factor of about 100 less sensitive toward the present water than thiophene. The steady state concentration crc is in the order of 10-9 mol/L in all three cases. The relative insensitivity of doping/undoping cycles with respect to the presence of water is discussed in terms of a lessened reactivity of the polarons and a low solubility of water in the heteroaromatic polymer.
    Additional Material: 10 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 4 (1966), S. 631-638 
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of basic aluminium dibenzoate upon the supercooling of polypropylene fractions of molecular weight 9.2 × 103-1.25 × 106 was determined by differential thermal analysis. The response to heterogeneous nucleation within the precision of the method used appears to be only slightly dependent, if at all, upon the molecular weight of the polymer.
    Additional Material: 4 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 673-685 
    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 model nucleating agent for polypropylene crystallization is described. A series of compounds consisting mainly of organocarboxylic acid salts is evaluated as heterogeneous nucleating agent for polypropylene crystallization by measuring their effect upon the polymer supercooling. Sodium benzoate and basic aluminium dibenzoate were among the best nucleating agents found. The nucleating abilities of the various compounds are discussed in terms of their structural features.
    Additional Material: 7 Tab.
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  • 5
    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 effect of cooling, nucleation, and spherulitic growth rates on the properties of polypropylene is discussed briefly. A differential thermal analysis technique is described for evaluating the relative extent of heterogeneous nucleation that occurs in a particular polypropylene composition. The method is based upon a nucleating agent's ability to reduce the relatively large amount of supercooling that occurs upon crystallization of polypropylene. Compounds are shown to vary widely in their effectiveness as heterogeneous nucleating agents in polypropylene. The relationships between the degree of supercooling of a particular polypropylene composition and its relative clarity, tensile properties, density, and morphology are shown.
    Additional Material: 12 Ill.
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  • 6
    ISSN: 0935-9648
    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
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  • 7
    ISSN: 0935-9648
    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: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 223 (1994), S. 217-233 
    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: Es wurde ein neues, wirtschaftliches Verfahren zur Herstellung von 2-Alkyl-2-oxazolinen mit gesättigten, ungesättigten und OH-funktionellen Alkylresten entwickelt, durch das Fettsären in polymerisierbare Monomere umgewandelt werden können.Die kationische Polymerisation der Fettalkyloxazoline wurde in unpolaren Lösungsmitteln und in Substanz untersucht. Sie verläft nach einem lebenden Mechanismus. Die Polymerisation ist gegen Verunreinigungen wie Wasser oder Ethanolamid bemerkenswert inert. Für die Substanzpolymerisation von 2-Pentadecyl-2-oxazolin wurde die Reaktionsenthalpie ΔH mit 85,9 kJ/mol bestimmt.
    Notes: A new, economic technique was developed for the production of 2-alkyl-2-oxazolines with saturated, unsaturated or OH-functionalized alkylrests. In the process the fatty acids are changed into polymerizable monomers.The cationic polymerization of fattyalkyl-2-oxazolines was investigated in unpolar solvents and in bulk. It reacts in a living mechanism. The polymerization is remarkable inert against impurities like water or ethanolamide. A reaction enthalpy of ΔH = 85,9 kJ/mol was found for the bulk polymerization of 2-pentadecyl-2-oxazoline.
    Additional Material: 6 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 2 (1968), S. 51-63 
    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: With the aid of an electrochemical initiated reaction of pure acrylonitrile in the presence of 0,1-1% water and of small concentrations of quaternary ammonium salts, an oligomeric, yellow, in acetone soluble compound was obtained with a molecular weight of 1000-3000. The high current-yield - up to 100 g/Ah, this means that per electrontransfer up to two polymeric molecules were obtained -, the low molecular weight, the independence of molecular weight of current density, the insensitivity to oxygen, and experiments of copolymerization with styrene indicate that the oligomer is formed at the cathode by an anionic mechanism. The influence of electrolyte structure, of cathode material, of current density, of water concentration, of convection, and of temperature on the formation of the oligomer has been investigated. A proposal of the structure of the oligomeric acrylonitrile has been made.
    Notes: Durch eine elektrolytisch gestartete Reaktion von reinem Acrylnitril in Gegenwart von 0,1 bis 1% Wasser und in Anwesenheit geringer Mengen eines quartären Ammoniumsalzes wurde ein oligomeres, acetonlösliches, gelbgefärbtes Produkt erhalten, dessen Molgewicht zwischen 1000 und 3000 liegt. Die hohe Stromausbeute - sie erreichte 100g/Ah, d. h. es wurden pro Elektronentransfer bis zu 2 Polymermoleküle gebildet -, das niedere Molgewicht, die Unabhängigkeit des Molgewichts von der Stromdichte, die Unempfindlichkeit gegen Sauerstoff sowie Co-polymerisationsversuche mit Styrol lassen darauf schließen, daß das Oligomere an der Kathode durch einen anionischen Mechanismus entstehen muß. Der Einfluß der Art des Leitsalzes, der Kathode, der Stromdichte, der Wasserkonzentration, der Konvektion und der Temperatu auf die Oligomerenbildung wurden untersucht. Ein Strukturvorschlag wird zur Diskussion gestellt.
    Additional Material: 6 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 39 (1990), S. 1241-1249 
    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: Concentrations of methylol carbamates in several crosslinking formulations prepared from methyl carbamate and formaldehyde and with and without urea or ethyleneurea as scavengers were determined by nuclear magnetic resonance spectroscopy. The scavengers were effective in reducing the free formaldehyde in the solution, but the dimethylol methyl carbamate concentration was reduced by about 25%. Selected chemical and physical properties were obtained from cotton fabrics finished with five different formulations of known composition. Fabric strengths were improved by use of a scavenger, but some undesirable side effects were observed.
    Additional Material: 3 Tab.
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