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  • 1975-1979  (8)
  • 1
    Electronic Resource
    Electronic Resource
    Molecular weights at ceiling and floor temperatures (1976)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 3465-3470 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1976.021771130
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  • 2
    Electronic Resource
    Electronic Resource
    Stereosequencing in poly(leucine) obtained from stereoselective polymerization of racemic leucine N-carboxy anhydride (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 463-474 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymerization of mixtures of D- and L-isomers of α-amino acid N-carboxy anhydrides follow normal copolymerization behavior, and sometimes even ideal copolymerization, which is conventionally interpreted as leading to a random distribution of monomer units along the polymer chains. Equations are dereived which relate the fraction of isotactic L-diads to experimental data from the previously reported methods involving sequential and stereospecific cleavage with enzymes. The application of these equations to poly(D,L-leucines), which were prepared by polymerization of racemic leucine N-carboxy anhydride with chiral and achiral primary amines as initiators, indicated that the polymers contain between 94 and 98% isotactic diads. The poly(leucines) thus consist of long stereoblocks despite the observed ideal copolymerization behavior.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790221
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  • 3
    Electronic Resource
    Electronic Resource
    Syndiotactic poly(leucine) (1978)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 579-590 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: N-(tert-Butoxycarbonyl)-L-leucyl-D-leucyl-L-leucyl-D-leucine tetrapeptide was synthesized from L- and D-leucine α-amino acids by conventional coupling methods. This tetrapeptide was transformed into an activated (polymerizable) tetrapeptide by conversion to the pentachlorophenyl ester and subsequent removal of the tert-butoxycarbonyl group. Condensation polymerizations of the activated tetrapeptide were performed in various solvents with triethylamine and N,N-diethyl-1-amino-2-propanol bases. Molar masses (“molecular weights”) of the resulting polymers were estimated to be in excess of 34000 g/mol. From optical rotation measurements in trifluoroacetic acid solution, it was found that the polymers were highly syndiotactic, although a small amount of isomerization (0,9-2,1%) occurred to yield polymers with a small excess of L-leucine residues. The degree of isomerization decreased with decreasing base strength and concentration and with decreasing polarity of the solvent; these effects were explained in terms of the simultaneous enolization and/or oxazolone-formation reactions.Preliminary studies of the conformation of syndiotactic poly(leucine) were performed with X-ray diffraction, NMR, IR and optical rotation methods. It was concluded that syndiotactic poly(leucine) most probably exists in a π-helical conformation with a preferred screw sense in both the solid state and in chloroform solution. NMR and optical rotation data on solutions in trifluoroacetic acid/chloroform showed that the polymer exhibits a conformational transition in the region of 4-10% trifluoroacetic acid content.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1978.021790303
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  • 4
    Electronic Resource
    Electronic Resource
    Carbon dioxide influence on NCA polymerizations (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 603-607 
    Details
    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
    URL: http://dx.doi.org/10.1002/macp.1977.021780229
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  • 5
    Electronic Resource
    Electronic Resource
    Polymerizable amphiphiles, 1. Synthesis and proton magnetic resonance studies of [3-(4-vinylphenyl)propyl]-β-D-glucopyranoside (1977)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 691-700 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The title compound 2 was synthesized and its micellization in water investigated by proton magnetic resonance at 260 MHz. Chemical shift changes with concentration were observed, the largest change being for the aromatic protons indicating ordered phenylene rings in the micelles. The critical micelle concentration of this compound in D2O at 37°C was found to be approximately 0,010g/cm3.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1977.021780306
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  • 6
    Electronic Resource
    Electronic Resource
    Multimerization: Association and aggregation, 14Part 13: cf.1.. Distinction between open and closed associations (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 365-371 
    Details
    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: Offene und geschlossene molekül-abhängige Assoziationen mit experimentell nur unvollständig bekannten Konzentrationsabhängigkeiten der scheinbaren Molekulargewichte können durch eine Auftragung der scheinbaren Gewichtsmittel (Mw)app des Molekulargewichtes gegen die reziproken scheinbaren Zahlenmittel (Mn)app-1 des Molekulargewichtes unterschieden werden. Für geschlossene Assoziationen sind für Theta-Systeme Geraden und für nicht-Theta-Systeme von Stäbchen konkave Kurven zu erwarten. Offene Assoziationen führen sowohl für Theta- als auch für nicht-Theta-Systeme in diesen Fällen zu konvexen Kurven. Beide Assoziationssysteme geben bei hohen Konzentrationen in nicht-Theta-Systemen Schleifen. Ähnliche Diagramme können mit scheinbaren z- und Gewichtsmitteln des Molekulargewichtes konstruiert werden.
    Notes: Open and closed molecule-based associations with experimentally incompletely accessible concentration dependencies of the apparent molecular weights can be distinguished by plotting the apparent weight average molecular weight, (Mw)app, versus the inverse apparent number average molecular weight, (Mn)app-1. For closed associations, straight lines are observed for theta-systems and concave ones for non-theta-systems of associating rods. Open associations in these cases give convex lines for both, theta and non-theta-systems. Loops can be expected for both types of associations for non-theta-systems at high concentrations. A similar plot can be based on apparent z and weight average molecular weights.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760210
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  • 7
    Electronic Resource
    Electronic Resource
    Influence of polymolecularity on the second virial coefficient of poly(α-methylstyrene)s in toluene (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 439-451 
    Details
    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: Durch anionische Polymerisation hergestellte Poly(α-methylstyrol)e wurden entsprechend Schulz-Flory-Verteilungen und logarithmischen Normalverteilungen gemischt, wobei jeweils das Gewichtsmittel des Molekulargewichtes zu 80 000 g mol -1 angesetzt wurde. Die zweiten Virialkoeffizienten aus Lichtstreuungsmessungen in Toluol bei 25°C waren mehr oder weniger unabhängig von der Polymolekularität. Die zweiten Virialkoeffizienten aus Messungen des osmotischen Drucfks stiegen jedoch für Proben mit logarithmischer Normalverteilung mit steigender Polymolekularität steil an, während sie für Schulz-Flory-Verteilungen absanken.
    Notes: Anionically polymerized poly(α-methylstyrene)s were mixed together to give Schulz-Flory and logarithmic normal distributions with a weight average molecular weight of 80 000 g mol-1 each. The second virial coefficients from light scattering in toluence at 25°C were more or less independent of the polymolecularity. The second virial coefficients from osmotic pressure measurements increased however strongly with increasing polymolecularity for mixtures with logarithmic normal distribution, whereas those for Schulz-Flory distributions decreased.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760215
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  • 8
    Electronic Resource
    Electronic Resource
    Kationenaustauscher in porösen glasperlenHerrn Professor Dr. W. Kern zum 70. Geburtstag gewidmet (1976)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 55 (1976), S. 129-139 
    Details
    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: Porous glass beads with bead diameters of 150-175 μm and pore diameters of 40-80 nm were filled with styrene/divinylbenzene. The monomer mixture was polymerized and the resulting copolymer within the pores was sulfonated.The exchange capacity of the ion exchange resin fixed in the interior of the porous glass beads is equal to that of a similar free ion exchange resin. The fixed ion exchange resin allows however much higher flow and exchange rates if pressures up to about 20 atü (2 MN/m2) are applied without compression of the material occurring with the free ion exchanger.
    Notes: Poröse Glaskugeln mit Durchmessern von 150-175 μm und Porenweiten von 40-80nm wurden mit Styrol/Divinylbenzol gefüllt. Die Monomermischung wurde polymerisiert und das in den Poren entstandene Copolymere sulfoniert.Die Austauschkapazität des in den porösen Glasperlen fixierten Ionenaustauschers ist gleich groß wie die eines ähnlichen freien Ionenaustauschers. Der Durchsatz und die Austauschgeschwindigkeit kann jedoch bei dem ersteren durch Anlegen von Drücken bis zu 20 atü (2 MN/m2) erheblich gesteigert werden, ohne daß wie bei den letzteren eine Kompression des Materials auftritt.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1976.050550111
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