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  • Polymer and Materials Science  (8)
  • Organic Chemistry  (3)
  • Life and Medical Sciences  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Processing stabilization of polyolefinsPaper presented at the 19th Colloquium of Danubian Countries on “Atmospheric Aging and Stabilization of Polymers” in Prague (Czechoslovakia), July 24 - 29, 1989 (1990)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 176 (1990), S. 215-230 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The response of a HDPE, a L-LDPE and a PP homopolymer to processing conditions and processing stabilizer formulations in the 220°C to 280°C temperature range was investigated. The technique of multiple extrusion was used. Melt flow and melt flow ratio were measured after the first, third and fifth extrusion pass. In the case of the HDPE and the L-LDPE, degradation by cross-linking was the predominant reaction and the molecular weight distribution showed a significant broadening compared to the virgin samples. The PP homopolymer degraded by chain scission. By adding a multifunctional hindered phenol and a hydrolysis resistant phosphite, all polymers could be efficiently protected against degradation on processing. For the HDPE and the L-LDPE, increased amounts of phosphite provided increased processing stability at constant phenol concentration. A 4:1 ratio of phosphite to phenol exhibited the best performance. The most efficient ratio for protecting melt flow of the PP homopolymer was found when a two to one ratio of phosphite to phenol was added.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1990.051760119
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  • 2
    Electronic Resource
    Electronic Resource
    Helix-coil stability constants for amino acids in nonaqueous solvents. Studies of random poly(γ-benzyl-L-glutamate-co-L-alanine) and poly(γ-benzyl-L-glutamate-co-L-leucine) in a mixed solvent (1981)
    New York : Wiley-Blackwell
    Biopolymers 20 (1981), S. 1435-1458 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The host-guest technique has been applied to the determination of the helix-coil stability constants of two naturally occurring amino acids, L-alanine and L-leucine, in a nonaqueous solvent system. Random copolymers containing L-alanine and L-leucine, respectively, as guest residues and γ-benzyl-L-glutamate as the host residue were synthesized. The polymers were fractionated and characterized for their amino acid content, molecular weight, and helix-coil transition behavior in a dichloroacetic acid (DCA)-1,2-dichloroethane (DCE) mixture. Two types of helix-coil transitions were carried out on the copolymers: solvent-induced transitions in DCA-DCE mixtures at 25°C and thermally induced transitions in a 82:18 (wt %) DCA-DCE mixture. The thermally induced transitions were analyzed by statistical mechanical methods to determine the Zimm-Bragg parameters, σ and s, of the guest residues. The experimental data indicate that, in the nonaqueous solvent, the L-alanine residue stabilizes the α-helical conformation more than the L-leucine residue does. This is in contrast to their behavior in aqueous solution, where the reverse is true. The implications of this finding for the analysis of helical structures in globular proteins are discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1981.360200707
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  • 3
    Electronic Resource
    Electronic Resource
    Untersuchungen über Carbazol-derivate I (1928)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 11 (1928), S. 1213-1219 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.192801101138
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  • 4
    Electronic Resource
    Electronic Resource
    On the mechanism of anionic polymerization of maleic anhydride, 2Part 1, cf.1.Extracts reported on occasion of the Macromolecular Colloquium 1972 in Freiburg i. Br., BRD. (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 170 (1973), S. 141-153 
    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: Die anionische Polymerisation von Maleinsäureanhydrid, initiiert mit Triphenylphosphin oder mit Tributylphosphin, wurde untersucht. Unter den gegebenen Reaktionsbedingungen entstanden Makro-Zwitterionen, deren Struktur vom jeweiligen Initiator bestimmt wurde. Im Falle der Polymerisationsauslösung mit Triphenylphosphin erhielt man Polymere, die Bernsteinsäureanhydrid-Gerüste und als deren Umlagerungsprodukt Cyclopentanonderivate enthielten. Bei der Polymerisationsauslösung mit Tributylphosphin gelangte man zu Polymerisaten, die weitgehend aus konjugierten Ketoolefinelementen bestanden. Zur Strukturaufklärung wurden IR, NMR- und massenspektroskopische Methoden benutzt. Die Makrozwitterionen wurden mittels Hochspannungselektrophorese nachgewiesen.Die Halbleitereigenschaften des aus konjugierten Ketoolefinelementen bestehenden Polymerisats werden diskutiert.Die Kinetik der Polymerisation von Maleinsäureanhydrid mit Triphenylphosphin wurde spektroskopisch untersucht. Die initiierende Reaktion des bei Reaktion mit dem Monomeren gebildeten Ylides war etwa 90 mal langsamer als das Kettenwachstum durch Addition des Monomeren an das wachsende Kettenende.
    Notes: The triphenyl and tributyl phosphine initiated polymerization of maleic anhydride was investigated. The structure of the macro zwitterions, formed under the given reaction conditions, depended on the initiator employed. If the polymerization was initiated by triphenyl phosphine, the macromolecules contained succinic anhydride units and cyclopentanone derivatives, formed from further rearrangement. If, however, tributyl phosphine was employed as initiator, the polymers were mostly made up of conjugated ketoolefinic units. IR, NMR and mass spectrometric measurements were carried out to determine the structure of the polymers. Existence of the macro zwitterions was proved by high voltage electrophoresis.The semi-conductor properties of the polymers containing conjugated ketoolefinic units are discussed.Spectroscopic investigation of the kinetics of the triphenyl phosphine initiated polymerization of maleic anhydride showed that the initiation reaction of the ylide, formed with the monomer, proceeded about 90 times slower than the propagation reaction due to addition of the monomer to the growing chain-end.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021700111
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  • 5
    Electronic Resource
    Electronic Resource
    Zur kenntnis der anionischen polymerisation von maleinsäureanhydrid (1972)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 153 (1972), S. 125-137 
    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: Maleic anhydride was found to polymerize spontaneously in presence of pyridine bases, triphenylphosphine and tributylphosphine. The formation of two characteristic types of structural elements during this polymerization can be explained with the aid of a reaction model. Analytical data (IR, NMR, and ESR spectroscopy, titrations) are given to characterize the structural elements of the polymers. Their compounds of degradation have been partially isolated and characterized.
    Notes: In Gegenwart von Pyridinbasen, von Triphenylphosphin oder Tributylphosphin polymerisiert Maleinsäureanhydrid spontan. Anhand eines Reaktionsmodelles wird die Bildung der beiden charakteristischen Strukturelemente in diesen Maleinsäureanhydridpolymerisaten erklärt. Die Strukturelemente der Polymeren wurden durch die analytischen Daten (IR-, NMR-, ESR-Spektroskopie, Titrationen) belegt. Zum Teil wurden die Abbauprodukte isoliert und identifiziert.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1972.021530110
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  • 6
    Electronic Resource
    Electronic Resource
    Helix-coil stability constants for the naturally occurring amino acids in water. XXI. Glutamine parameters from random poly(hydroxypropylglutamine-co-L-glutamine) and poly(hydroxybutylglutamine-co-L-glutamine) (1982)
    New York : Wiley-Blackwell
    Biopolymers 21 (1982), S. 51-77 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Water-soluble, random copolymers containing L-glutamine and either N5-(3-hydroxypropyl)-L-glutamine or N5-(4-hydroxybutyl)-L-glutamine were synthesized, fractionated, and characterized. The thermally induced helix-coil transitions of these copolymers were studied in water. A short-range interaction theory was used to deduce the Zimm-Bragg parameters σ and s for the helix-coil transition in poly(L-glutamine) in water from an analysis of the melting curves of the copolymers in the manner described in earlier papers. The computed values of s indicate that L-glutamine is helix-indifferent at low temperature and a helix-destabilizing residue at high temperature in water. At all temperatures in the range of 0-70°C, the glutamine residue promotes helix-coil boundaries since the computed value of σ is large.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360210106
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  • 7
    Electronic Resource
    Electronic Resource
    A new class of photopolymers with pendent dimethylmaleimide groupsPart II: cf.2.. III. Comparative study of different photopolymers with pendent olefinic structures including dimethylmaleimide groups (1985)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 133 (1985), S. 147-170 
    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: Durch polymeranaloge Reaktion von Polyvinylalkohol mit Carbonsäurechloriden wurde eine Serie von lichtvernetzenden Photopolymeren mit demselben Polymerrückgrat, aber mit verschiedenen seitenständigen Chromophoren hergestellt: den vier Imidylderivaten Dimethylmaleinimid, 4-Methyl-3,4,5,6-tetrahydrophthälsaureimid, 3,4,5,6-Tetrahydrophthalsäureimid und 3,4-Dihydro-1,2-naphthalindicarbonsäureimid, sowie trans-3-Phenyl-propensäure (Zimtsäure) und 1,3-Diphenyl-2-propenon (Chalkon). Die Photoempfindlichkeit der mit Thioxanthon sensibilisierten Polymeren wurde nach der Gelpunktmethode und mittels der photographischen Stufenkeilmethode bestimmt. Für unsensibilisierte Filme des Chalkon- sowie des 3,4-Dihydro-1,2-naphthalindicarbonsäureimidylpolymeren konnte der Zusammenhang zwischen Belichtung und Umsetzung an photovernetzbaren Gruppen quantitativ ermittelt werden. Bei monochromatischer Belichtung bei 365 nm waren sensibilisierte und unsensibilisierte Imidylpolymere eine Größenordnung empfindlicher als die Polymeren mit Chalkon- und Zimtsäuregruppen.
    Notes: A series of photopolymers with the same polymer backbone but with different pendent chromophors including four imidyl structural units  -  dimethylmaleimide, 4-methyl-3,4,5,6-tetrahydrophthalic acid imide, 3,4,5,6-tetrahydrophthalic acid imide, and 3,4-dihydro-1,2-naphthalene dicarboxylic acid imide  -  as well as trans-3-phenyl propenoyl (cinnamoyl) and 1,3-diphenyl-2-propenonyl (chalcone) units were synthesized by polymer analogous reaction of the corresponding carboxylic acid chloride derivatives with poly(vinyl alcohol). The polymers, sensitized with thioxanthone, were characterized by their minimal exposure energies derived from gel point as well as photographic sensitivity measurements. Quantitative relations between chromophore conversion and exposure were established for unsensitized films of the chalcone and the 3,4-dihydro-1,2-naphthalene dicarboxylic acid imidyl polymer. Upon irradiation with monochromatic 365 nm light the sensitized and unsensitized imidyl polymers proved to be one order of magnitude more sensitive than the chalcone and cinnamoyl polymers.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1985.051330112
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  • 8
    Electronic Resource
    Electronic Resource
    A new class of photopolymers with pendent dimethylmaleimide groups. II. Photocrosslinking of homo- and copolymers of N-(5-methyl-3-oxa-4-oxohexen-5-yl)-dimethylmaleimidePart I: cf.1 (1984)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 128 (1984), S. 71-97 
    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: Durch Polymerisation von N-(5-Methyl-3-oxa-hexen-5-yl)-dimethylmaleimid (DMI-MA) werden Polymethacrylate mit anhängenden, lichtvernetzbaren Dimethylmaleinimid (DMI)-Gruppen erhalten. Eine Reihe von DMI-MA Homopolymeren verschiedenen Molekulargewichts (60 000-520 000) und eine Reihe von Copolymeren aus DMI-MA und Methylmethacrylat (MMA) mit unterschiedlichem DMI-Gehalt (6 - 78 mol-%) wurden hergestellt. DMI-haltige Photopolymere zeigen hohe Lichtempfindlichkeit (6 mJ cm-2 bei 365 nm). Die Belichtungsenergien zur Vernetzung dünner, mit Thioxanthon sensibilisierter Polymerfilme mit Licht der Wellenlänge 365 nm wurden nach zwei Methoden bestimmt: mit dem photographischen Graukeil fur Filme auf Kupferfolie und durch Bestimmung der Gelfraktion fur Filme auf transparentem Quarztriger. Die Belichtungsenergien sind direkt dem Molekulargewicht und dem Molenbruch an DMI-Gruppen proportional. Die Photoempfindlichkeit als Funktion der Sensibilisatorkonzentration durchlguft ein Maximum. Die Resultate stimmen mit Theorien uber die Photovernetzung überein.
    Notes: The polymerization of N-(5-methyl-3-oxa-4-oxo-hexen-5-yl)-dimethylmaleimide (DMI-MA) yields poly(methacrylates) with pendent light sensitive dimethylmaleimide (DMI) groups. A series of DMI-MA homopolymers with different molecular weights (60.000-520.000) and a series of copolymers of DMI-MA with methylmethacrylate (MMA) with varying DMI content (6-78 mol-%) were prepared. DMI-containing polymers show high photosensitivity (6 mJ cm-2 at 365 nm). Exposure energies to insolubilize thin solid photopolymer coatings sensitized with thioxanthone were determined with monochromatic radiation at 365 nm by two different methods: by the photographic step tablet method for coatings on copper substrates and by establishing the gel point exposure for coatings on transparent quartz supports. Minimum exposure energies are linear functions of the molecular weight and of the DMI molar fraction of the polymers. Sensitivity as a function of the sensitizer concentration shows a maximum. The results agree well with theories of photocrosslinking.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1984.051280104
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  • 9
    Electronic Resource
    Electronic Resource
    Neue photoreaktive Polymere mit seitenständigen Dimethylmaleinimid-Gruppen. I. Radikalische homo-und copolymerisation von N-(5-methyl-3-oxa-4-oxo-hexen-5-yl)-dimethylmaleinimid (1983)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 115 (1983), S. 163-181 
    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: The homopolymerisation of N-(5-methyl-3-oxo-4-oxo-hexen-5-yl)-dimethylmaleimide (DMI-MA) leads to linear poly(methylmethyacrylates) with pendant lightsensitive dimethylmaleimide groups. Due to steric hindrance of the methyl substitutents, the carbon-double bond is not involved in the reaction, even at conversions of over 90%. The reaction velocity constant for the homopolymerisation is kp/kt0,5 = 2,0 - 2,2.10-2 (65°C, toluene, AIBN) and the activation energy Ea = 62,36 ± 2 KJ/mol-1.Measurement of the copolymerisation reactivity ratios for the monomer pairs DMI-MA/methacrylic acid (MAS), DMI-MA/methylmethacrylate (MMA) and DMI-MA/ethylacrylate (EA) gave the following values: DMI-MA (r1): MAS (r2) = 1,36 ±0,06 : 0,77: ± 0,06; DMI-MA (r1) : MMA (r2) = 1,16 ± 0,17:0,475 ± 0,17 and DMI-MA (r1): EA(r2) = 1,60 ± 0,15: 0,44 ± 0,15.
    Notes: Die Homopolymerisation von N-(5-Methyl-3-oxa-4-hexen-5-yl)-dimethylmaleinimid (DMI-MA) führt zu linearen Polymethylmethacrylaten mit seitenständigen lichtvernetzbaren Dimethylmaleinimid-Gruppen. Dabei nimmt die —C=C— Doppelbindung des Imidylrestes infolge sterischer Hinderung durch die beiden Methylsubstituenten, selbst bei Umsätzen von über 90%, nicht an der Reaktion teil. Für die Homopolymerisation wurde die Polymerisationsgeschwindigkeitskonstante bestimmt zu kp/kt0,5 = 2,0 - 2,2·10-2(65°C, Toluol, AIBN); die Aktivierungsenergie beträgt Ea = 62,36 ± 2 kJ/mol-1.Aus den Copolymerisationen der Monomerpaare DMI-MA/Methacrylsäure (MAS), DMI-MA/Methylmethacrylat (MMA) und DMI-MA/Ethylacrylat (EA) ergaben sich folgende Copolymerisationsparameter: DMI-MA (r1) : MAS (r2) = 1,36 ± 0,06 : 0,77 ± 0,06; DMI-MA (r1) : MMA (r2) = 1,16 ± 0,17 : 0,475 ± 0,17 und DMI-MA (r1) : EA (r2) = 1,60 ± 0,15 : 0,44 ± 0,15.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1983.051150114
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  • 10
    Electronic Resource
    Electronic Resource
    Über die Decarboxylierung von Galakturonsäure mit Schwermetallionen (1956)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 39 (1956), S. 662-667 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1. D-Galacturonic acid is partially decarboxylated in water by heavy metal ions at 96° under weakly acidic conditions. No furfurol, but arabinose is formed. The mtalytic action increases in the following order: Mgf+ 〈 Zn++ 〈 Ni++ 〈 Al+++ 〈 Pb++.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19560390303
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