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  • 1
    Electronic Resource
    Electronic Resource
    Zur Definition der chemischen Uneinheitlichkeit von CopolymerisatenHerrn Dr. ERNST TROMMSDORFF zum 65. Geburtstag gewidmet (1970)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 11 (1970), S. 63-72 
    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 copolymerization of two or more components results in chemical heterogeneous products. The known quantitative definitions of the heterogeneity are not satisfying since they refer only to a limited part of the conversion and are not based on an obvious mathematical dependence upon the heterogeneity of the polymers. There is only a plausible connection between them.As result of a quantitative analysis of the term „heterogeneity“ a general definition was found, comprising the standard deviation suggested by ELIAS as measure for the heterogeneity as a special case. The new definition permits a more specialized consideration in case of copolymers with an equal frequency distribution but a different dependence of the properties on the distribution.
    Notes: Bei der Copolymerisation von zwei oder mehr Komponenten entstehen chemisch uneinheitliche Produkte. Zur Kennzeichnung der Uneinheitlichkeit durch eine Maßzahl wurden einige Definitionen bekannt, die aber nicht befriedigen, weil sie entweder nur einen beschränkten Teil des Umsatzintervalls berücksichtigen oder weil kein mathematisch durchsichtiger, sondern nur plausibler Zusammenhang mit der Polymerisatuneinheitlichkeit besteht.Eine anschauliche, aber quantitative Analyse des Begriffs „Uneinheitlichkeit“ führts auf eine allgemeine Definition, welche die von ELIAS als Uneinheitlichkeitsmaß vorgeschlagene Standardabweichung quasi als Sonderfall enthält. Die neue Definition erlaubt eine differenziertere Betrachtungsweise bei Copolymerisaten mit gleicher Häfigkeitsverteilung aber unterschiedlicher Abhängigkeit der Eigenschaften von der Verteilung.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1970.050110106
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  • 2
    Electronic Resource
    Electronic Resource
    A new class of thermoplastic elastomers based on polypivalolactone graft systemsContribution No. 360. (1977)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 58 (1977), S. 345-372 
    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: Die unter Ringöffnung verlaufende Pfropfpolymerisation von Pivalolacton führt zu hochwertigen thermoplastischen Elastomeren; als Initiatoren dienen Carboxylatanionen, die sich statistisch verteilt an einem geeigneten polymeren Substrat befinden. Bei der thermoplastischen Verarbeitung kristallisieren die Poly[pivalolacton]-Segmente leicht aus; sie bilden diskontinuierliche Bereiche, die als verstärkende Vernetzungsstellen dienen und die bei 12-225°C, je nach dem durchschnittlichen Polymerisationsgrad der Pfropfsegmente (P̄n = 4-90), schmelzen. Die Bereiche sind, wie durch Transmissionselektronenmi-kroskopie festgestellt wurde, 5-100 nm groß.Poly[(äthylen-co-propylen-co-l,4-hexadien)-g-pivalolacton] (aus carboxyliertem Ausgangspolymeren hergestellt) und Poly[(äthylacrylat)-g-pivalolacton] wurden eingehend untersucht; ihre physikalischen Eigenschaften entsprechen denen der in der üblichen Art und Weise vulkanisierten und verstarkten Ausgangspolymeren. Der Einfluß von Strukturänderungen auf die Morphologie und die Eigenschaften wird erörtert.
    Notes: Ring-opening graft polymerization of pivalolactone, initiated by carboxylate anion which is randomly located on suitable polymeric substrates, affords high quality thermoplastic elastomers. When processed from the melt, poly(privalolactone) segments readily crystallize into discontinuous domains which serve as reinforcing network tiepoints and melt at 120-225°C according to the average degree of polymerization (P̄n = 4-90) of the graft segments. Transmission electron microscopy shows domain size to be 5-100 nm.Poly([ethylene-co-propylene-co-1,4-hexadiene]-g-pivalolactone) (from carboxylated base polymer) and poly([ethyl acrylate]-g-pivalolactone) were evaluated in detail and have physical properties similar to conventionally cured and reinforced base polymers. The effects of structural variables on morphology and properties are discussed.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1977.050580115
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  • 3
    Electronic Resource
    Electronic Resource
    Electrochemical characterization of aminated PVC-based ion-selective membranesDedicated to the memory of Prof. Wilhelm Simon. (1993)
    Weinheim : Wiley-Blackwell
    Electroanalysis 5 (1993), S. 725-730 
    Details
    ISSN: 1040-0397
    Keywords: Ion selective electrodes ; pH sensors ; aminated PVC ; impedance measurements ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The potentiometric and impedance characteristics of a large number of pH sensitive, piperazine-based aminated PVC membranes are summarized. The main goal of the work was to predict the differences between “good” and “bad” responsive potentiometric pH membranes with very similar overall nitrogen contents. The only conclusion gained previously from other methods was that the N content should be between 0.5 and 0.8% for Nernstian response. The detailed analysis of the data show that a given N content of the basic material is a necessary but not a sufficient requirement with respect of the quality of potentiometric response. Conditions for appropriate pH response of the membrane are formulated in terms of surface and bulk impedance characteristics. The ideal pH response of an optimized aminated PVC membrane, which corresponds to a minimum surface impedance, is presented. The primary importance of surface amines relative to bulk amines (the conformation and distribution of active sites) is proven in a simple experiment.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/elan.1140050904
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  • 4
    Electronic Resource
    Electronic Resource
    Unequivocal synthesis of bis(2-cyanoacrylate) monomers. I. Via anthracene adducts (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 2475-2507 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An unequivocal and general synthesis of bis(2-cyanoacrylate) monomers from Diels-Alder adducts of the alkyl 2-cyanoacrylates has been developed. Saponification of the anthracene adduct of either isobutyl or ethyl 2-cyanoacrylate to the anthracene/2-cyanoacrylic acid adduct, conversion of the latter to the alkali salt or acid chloride derivatives, followed by respective esterification reactions with an organic dihalide or glycol gave the bis-anthracene adduct precursors to the bis(2-cyanoacrylate) monomers. Heating the bis-adducts with excess maleic anhydride in refluxing xylene effected retrograde diene scission to the bis(2-cyanoacrylate) monomers in up to 80% overall yields. Comonomer blends of the difunctional bis(2-cyanoacrylates) with the alkyl 2-cyanoacrylates gave crosslinked polymeric adhesive compositions exhibiting higher bond strengths under both dry and wet conditions than the noncrosslinked cyanoacrylate adhesives. Potential applications of interest are as pit and fissure sealants in dentistry and for the direct bonding of orthodontic attachments.
    Additional Material: 10 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.170161007
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  • 5
    Electronic Resource
    Electronic Resource
    Polypivalolactone grafts on EPDM (1978)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 16 (1978), S. 539-560 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Random copolymers of ethylene, propylene, and 1,4-hexadiene (EPDM) were carboxylated by reaction with thioglycolic acid or with maleic anhydride. Treatment of these polymers in tetrahydrofuran solution with tetrabutylammonium hydroxide generated carboxylate anions, which initiated the graft polymerization of pivalolactone. Conversion and grafting efficiencies approached 100%. Polypivalolactone chains had an estimated DPn of 3 to 20 and the average distance between graft sites varied from 3000 to 7700 molecular weight units. On cooling from the melt, highly crystalline domains of polypivalolactone formed, which melted at 120-200°C depending on DPn. Electron microscopy and x-ray analysis verified the presence of these domains, which serve as reinforcing tiepoints for thermally reversible network formation. The resultant thermoplastic elastomers have excellent elasticity and strength, and their compression set resistance is equivalent to that of conventionally cured and reinforced EPDM. This paper details the synthesis, morphology, and structure-property relationships of these elastomers.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1978.170160302
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  • 6
    Electronic Resource
    Electronic Resource
    Entfernung von Tensiden aus AbwässernVortrag auf dem Jahrestreffen der Verfahrens-Ingenieure, 30. Sept. bis 2. Okt. 1975 in Karlsruhe. (1976)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 48 (1976), S. 345-345 
    Details
    ISSN: 0009-286X
    Keywords: Abwasserreinigung ; Tenside ; Schaumtrennung ; Blasenkolonne ; Recycling ; II-Theorem ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330480424
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  • 7
    Electronic Resource
    Electronic Resource
    Protein complexation with DNA phosphates as a cause for DNA duplex destabilization: A thermodynamic model (1989)
    New York : Wiley-Blackwell
    Biopolymers 28 (1989), S. 1653-1665 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Complexation of positively charged sites in a protein with the negative DNA phosphate groups shields the phosphate charges. This diminishes interstrand electrostatic repulsions, which stabilizes the duplex. When phosphate shidlding is present in one DNA strand only, the conformation of this strand changes due to a decrease of intrastrand phosphate-phosphate repulsions. This destabilizes the duplex since then the strands differ in conformation. A thermodynamic model is formulated to describe this stabilization/destabilization effect in terms of changed enthalpies and entropies of hybridization. It is found that protein complexation with one DNA strand can indeed lower the TM value of a duplex. The model is applied to the action of helicases (replication), RNA polymerases (transcription), and restriction endonucleases. Mechanisms with unilateral charge shielding are proposed for their duplex-destabilizing properties.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360281002
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  • 8
    Electronic Resource
    Electronic Resource
    Dielectric properties of an epoxy resin and its composite II. Solvent effects on dipole relaxation (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 33 (1987), S. 2293-2303 
    Details
    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: Dipole relaxation dielectric loss behavior of a fiberglass-epoxy composite has been studied following submersion in polar and nonpolar organic solvents as well as in acidic and basic aqueous solutions. Certain adsorbed organic solvents, such as 1,2-dichloroethane, had little influence on the epoxy relaxation behavior. Other solvents, including chloroform, increased the composite relaxation intensity and shifted the temperature-frequency region over which the relaxation occurred. Both the amount of solvent uptake and the degree of interaction of solvent molecules with epoxy polar functional groups appear to control the amount of relaxation behavior perturbation. Arrhenius activation energies for relaxation were lowered by solvent uptake from the dry composite value of 18 kcal/M to between 6 and 16 kcal/M, depending on the solvent adsorbed. Submersion in methanol and chloroform sharply increased the direct current conductivity of the composite. Two molar acidic and basic solutions had little influence on composite dipole relaxation behavior other than the well known behavior associated with moisture uptake.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1987.070330703
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  • 9
    Electronic Resource
    Electronic Resource
    Dielectric properties of an epoxy resin and its composite I. Moisture effects on dipole relaxation (1986)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 31 (1986), S. 1771-1784 
    Details
    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: Dipole relaxation dielectric loss behavior of a fiberglass-epoxy composite has been studied as a function of moisture uptake. A single widely distributed loss peak, centered at -16°C for 10 kHz measurement, is observed in the dry composite. Very low moisture concentrations (〈0.1%) interact with the composite, through either dipole pairing or by inducing chemical changes, to decrease loss intensity. At moisture concentrations from 0.1 to 1.4%, loss peak intensity generally increases with moisture uptake. Over this moisture concentration range water dipoles presumably relax in phase with the epoxy segments or side groups upon which they adsorb. Arrhenius relaxation activation energy decreases, and improved loss peak definition at increasing moisture concentrations is interpreted as indicating resin plasticization by adsorbed moisture. At moisture concentrations above 1.4%, the appearance of a second loss peak suggests formation of a new colloidal or weakly adsorbed moisture phase, as well as the saturation of primary adsorption sites.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1986.070310622
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  • 10
    Electronic Resource
    Electronic Resource
    Telechelic polymers (1960)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 46 (1960), S. 535-539 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1960.1204614825
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