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  • Polymer and Materials Science  (15)
  • 550 - Earth sciences
  • DATE/TIME; Date/time end; Elevation, maximum; Elevation, minimum; GLAC; Glaciers Austria; Kesselwandferner; Kesselwandferner, Ötztaler Alpen, Austria; KWF; Mass balance, total of the altitude zone; Sampling/measurements on glacier; Specific mass balance of the altitude zone; Total area of the altitude zone
  • SPACECRAFT PROPULSION AND POWER
  • 1970-1974  (16)
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Keywords
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Year
  • 1
    Electronic Resource
    Electronic Resource
    HR-NMR study of formation and structure of the stereocomplex of poly(methyl methacrylate) in solution (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 2939-2956 
    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: Aus hochaufgelösten Kernresonanzspektren wurde der Gehalt p an assoziiertem Stereokomplex in Lösungen von isotaktischem und syndiotaktischem Poly(methyl methacrylat) bestimmt. Mit Hilfe der p-Werte wurde festgestellt, daß in aromatischen Lösungsmitteln die minimale Länge der assoziierten syndiotaktischen Sequenzen ca. 10 Monomereinheiten beträgt, in CCl4 und CD3CN ist die minimale Länge ca. 3 Monomereinheiten. Im assoziierten Stereokomplex ist das Verhältnis der Monomereinheiten von isotaktischen und syndiotaktischen Sequenzen (iso:syndio) = 1:1,5; die Dissoziation des Stereokomplexes erinnert bei Erhöhung der Temperatur an das Schmelzen von Mikrokristallen. Der Schmelzpunkt der assoziierten Segmente steigt in einem gegebenen Lösungsmittel mit der Länge der assoziierten Sequenzen.
    Notes: From high-resolution NMR spectra of mixtures of solutions of isotactic and syndiotactic poly(methyl methacrylate), the content p of the associated stereocomplex was determined. From the values of p, the minimum length of associated syndiotactic sequences was found to be ca. 10 monomeric units in aromatic solvents and ca. 3 such units in CCl4 and CD3CN. In the associated stereocomplex the ratio of monomeric units in isotactic and syndiotactic sequences is (iso/syndio) = 1:1,5; the process of dissociation of the stereocomplex with increasing temperature is reminiscent of the melting of microcrystallites. The melting point of associated segments in a given solvent increases with the length of the associated sequences.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021751014
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  • 2
    Electronic Resource
    Electronic Resource
    Über den thermo-oxidativen Abbau von Polyvinylacetat unter thermogravimetrisch-dynamischen Bedingungen (1974)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 175 (1974), S. 3437-3445 
    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: The present work discusses the results of studies on the elimination of acetic acid from poly(vinyl acetate) in air under thermogravimetric-dynamic conditions. The dependence of the kinetic parameters on the degree of transformation, the heating rate and on the average molecular weight of the studied samples, as well as the presence of an exothermic process at the end of the first degradation step indicate a modification of the reaction mechanism, probably because of the superposition of an oxidation process at higher temperatures.
    Notes: In der vorliegenden Arbeit werden die Ergebnisse von Untersuchungen über das Abspalten von Essigsäure aus Polyvinylacetat an Luft unter thermogravimetrisch-dynamischen Bedingungen besprochen. Die Abhängigkeit der kinetischen Größen vom Umsatz, der Aufheizgeschwindigkeit und dem mittleren Molekulargewicht der untersuchten Proben, sowie das Vorhandensein eines exothermen Prozesses gegen Ende der ersten Abbaustufe deuten auf eine Änderung des Reaktionsmechanismus, wahrscheinlich infolge einer Überlagerung durch einen Oxidationsprozeß bei höheren Temperaturen, hin.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1974.021751210
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  • 3
    Electronic Resource
    Electronic Resource
    Berichte über Tagungen und Messen (1972)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 3 (1972), S. 98-103 
    Details
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19720030212
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  • 4
    Electronic Resource
    Electronic Resource
    Korrosionsschutz durch Duromere (1971)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 22 (1971), S. 222-225 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Corrosion protection by duromeric materialsDuromeric materials as coating materials can be easily form thin coatings, are superior with respect to temperature resistance to plastomeric and elastomeric materials and are easily modified. On the other hand duromeric coatings are brittle and little resistant to temperature variations and they require furnaces for curing. The protection is influenced by various factors including application method, surface preparation, distortion and elongation of the particular piece and specific properties of the medium to which the coating is exposed. In this connection, pH value and electrode potential are vital factors, although the exact mechanism has not yet been established.
    Notes: Duromere als Beschichtungsstoffe lassen sich leicht auftragen, bilden dünne Schichten, sind höher temberaturbeständig als Plastomere und Elastomere und lassen sich leicht modifizieren. Andererseits sind Duromerschichten spröde und nicht sehr beständig gegen Temperaturwechsel, und sie erfordern zum Aushärten Öfen. Die Schutzwirkung wird durch zahlreiche Faktoren beeinflußt. Hierzu gehören die Auftragstechnik, die Vorbereitung der Metalloberfläche, Vorformungs- und Dehnungszustände des jeweiligen Werkstücks sowie die spezifischen Eigenschaften des einwirkenden Mediums. Dabei spielen pH-Wert und Elektrodenpotential eine ausschlaggebende Rolle, wobei über den genauen Mechanismus noch keine Klarheit besteht.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19710220306
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  • 5
    Electronic Resource
    Electronic Resource
    Polychalkone, IVIII. Mitt. Makromol. Chem. 157 (1972) 179.. Gaschromatographisch-pyrolytische untersuchungen wärmebeständiger polychalkone (1973)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 169 (1973), S. 129-135 
    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: The present paper deals with investigations on the thermal stability and the structure of some polychalcones by means of pyrolysis-gaschromatography. The decrease of electronic interaction due to the interruption of conjugation of the π-electronic system in the main chain of macromolecules is also reflected in the resulting chromatograms.
    Notes: In der vorliegenden Arbeit werden aus gaschromatographisch-pyrolytischen Untersuchungsergebnissen einige Aussagen über die Wärmebeständigkeit und Struktur von Polychalkonen abgeleitet. Es zeigt sich, daß die Abschwächung der Elektronenwechselwirkung durch Unterbrechung der Konjugation des π-Elektronensystems in der Hauptkette der Makromoleküle sich in den erhaltenen Chromatogrammen widerspiegelt.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1973.021690113
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  • 6
    Electronic Resource
    Electronic Resource
    Dilute solution characterization of polyfluoroalkoxyphosphazenes (1972)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A-2: Polymer Physics 10 (1972), S. 699-713 
    Details
    ISSN: 0449-2978
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Results from the dilute solution characterization of polyfluoroalkoxyphosphazenes in Freon ether (E2) solutions are reported. Anomalous viscosity data suggest that polymer aggregation sometimes occurs in E2 and may be caused by the presence of relatively few anomalous polar groups on the polymer backbone. Since small amounts of acetone added to the E2 solutions inhibit aggregate formation, samples are also characterized in an E2-acetone mixed solvent. Light scattering and osmometry indicate that E2 and E2-acetone (9.09% by volume) are theta solvents for the polymers. High molecular weights (M̄w 〈 3 × 106) and unusually broad molecular weight distributions (M̄w/M̄n 〈 16) are found. One polymer is fractionated by extracting solutions in 1,1,2-trichloro-1,2,2-trifluoroethane with acetone. Although the samples are highly polydisperse, intrinsic viscosities correlate with number-average molecular weights satisfying the Mark-Houwink relation with the exponent a ≈ 1/2. The z-average mean-square radius of gyration increases linearly with molecular weight so that 〈S2〉g/M̄w ≈ 0.098. Because of the large polydispersity and unknown form of the distribution function, a quantitative interpretation of characterization results relating dilute solution parameters to polymer skeletal structure is not possible. The tentative conclusion is that the fluoroalkoxy-substituted phosphazene polymers are relatively linear and therefore that the broad distribution of molecular weights must be due to some polymerization mechanism other than branching.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1972.160100412
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  • 7
    Electronic Resource
    Electronic Resource
    Synthesis and characterization of polyaryloxyphosphazenes (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 12 (1974), S. 433-444 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis, dilute solution characterization, and thermal analysis of seven polyaryloxyphosphazenes are described. Synthesis is accomplished by the ring-opening polymerization of hexachlorocyclotriphosphazene at 245°C, followed by reaction of polydichlorophosphazene with sodium aryloxide salts in solution at 115°C. Polymers prepared and characterized have the general structure [(ArO)2PN]n, with Ar = C6H5, m- and p-CH3C6H4, m- and p-ClC6H4, p-C2H5C6H4, or p-CH3OC6H4. Elemental and infrared analyses show these polymers are essentially free of reactive chlorine sites. All the polymers displayed high intrinsic viscosities [η] 〉 1 dl/g, in tetrahydrofuran or chloroform. Closer examination of the dilute solution properties of two polyaryloxyphosphazenes revealed high molecular weights (M̄w〉 6 × 105) and broad molecular weight distributions (M̄w/M̄n 〉 4.7). The experimental values for the Z-average radii of gyration, 〈S2〉z1/2, characterized at near theta conditions, are larger than the calculated values for a freely rotating chain, which suggests that these polymers are relatively linear and not highly branched. Thermal analysis revealed second-order glass transitions between -37 and +13°C and first-order endothermic transitions between 43 and 160°C for the different polymers. Although crystalline structure can persist above this first-order transition, this temperature can be regarded as a melting temperature or softening temperature at which films can be molded. Decomposition temperatures, measured in argon and oxygen, ranged from 250°C to 400°C.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.170120214
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  • 8
    Electronic Resource
    Electronic Resource
    Fluoreszenzspektroskopische Untersuchungen an Polyacenaphthylen und Copolymeren aus Styrol und Acenaphthylen (1971)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 146 (1971), S. 181-193 
    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: Polyacenaphthylene shows excimer fluorescence in solid state and in solution at room temperature, which is not observed from copolymers of acenaphthylene and styrene. In these copolymers excitation energy is transferred from the units of styrene to those of acenaphthylene. In the solid state at room temperature excitation of the styrene units yields the fluorescence of the acenaphthylene units even from copolymers with small concentrations of acenaphthylene. The effect of energy migration occurs, too, in 2-methyltetrahydrofurane at 77 and 298°K, but to a much smaller extent. The mechanisms of energy migration are discussed.
    Notes: Polyacenaphthylen zeigt sowohl im Festzustand als auch in Lösung bei Raumtemperatur eine Excimerenfluoreszenz, die bei Copolymeren aus Acenaphthylen und Styrol nicht auftritt. Bei diesen Copolymeren erfolgt eine Wanderung der Anregungsenergie von den Styrol- zu den Acenaphthylenbausteinen, so daß bei Raumtemperatur selbst aus festen Copolymeren mit geringem Acenaphthylengehalt bei Anregung der Styrolbausteine nur die Fluoreszenz der Acenaphthylenbausteine emittiert wird. In 2-Methyltetrahydrofuran-Lösungen bei 77 und 298°K wird der Wanderungseffekt ebenfalls, jedoch wesentlich schwächer, beobachtet. Die Mechanismen der Energieübertragung werden diskutiert.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1971.021460119
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  • 9
    Electronic Resource
    Electronic Resource
    Beiträge zur perlpolymerisation des vinylacetats. 1. Über die kinetik der perlpolymerisation (1970)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 132 (1970), S. 259-268 
    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: The influences of the initiator- and the PVA-concentration as well as of the rate of stirring upon the reaction rate of the suspension polymerization of vinyl acetate were studied. This polymerization is determined by the rate of stirring and obeys own laws, so that it is not possible to identify the suspension polymerization with a “finely divided bulkpolymerization cooled with water”.
    Notes: Es wird der Einfluß der Initiator- und Polyvinylalkoholkonzentration sowie der Rührgeschwindigkeit auf die Reaktionsgeschwindigkeit der Perlpolymerisation des Vinylacetats untersucht und gefunden, daß die Perlpolymerisation von der Rührgeschwindigkeit abhängig ist. Aus diesem Ergebnis wird geschlossen, daß die Perlpolymerisation in diesem Fall nicht uneingeschränkt als eine „wassergekühlte Massenpolymerisation in fein verteiltem Zustand“ angesechen werden kann, sondern eigene Gesetzmäßigkeiten befolgt.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1970.021320123
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  • 10
    Electronic Resource
    Electronic Resource
    Über die kinetik des thermischen abbaues von polystyrolenVortrag auf dem IUPAC-Symposium für Makromolekulare Chemie im August 1969 in Budapests. „Kinetics and Mechanism of Polyreactions“, IUPAC Symposium on Macromolecular Chemistry, 1969, Vol. V, p. 305 (Sect. 11, Preprint 33). (1970)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 131 (1970), S. 55-62 
    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: The results of the kinetic isothermal, thermal-dynamic (i.e. with constant heating rate) and of the gaschromatographic-pyrolytic study of the thermal degradation of different polystyrenes show the mechanism of the degradation reaction to be complex and not simple depolymerisation. The kinetic parameters of the thermal degradation depend as well on the molecular weight as on the nature of the polystyrene and the degree of conversion. On these reasons, one observes under thermal-dynamic conditions an influence of the heating rate on the total activation energy.
    Notes: Die Ergebnisse der kinetisch-isothermen, thermisch-dynamischen (d. h. mit konstanter Aufheizgeschwindigkeit) und gaschromatographisch-pyrolytischen Untersuchungen des thermischen Abbaues von verschiedenen Polystyrolen lassen darauf schließen, daß der Abbaumechanismus komplexer Natur ist und nicht nur nach einem einfachen Depolymerisationsmechanismus verläuft. Die kinetischen Parameter des thermischen Abbaus sind sowohl vom Molekulargewicht als auch von der Art des Polystyrols und dem Umsatzgrad abhängig. Aus diesem Grunde wird unter thermisch-dynamischen Bedingungen auch ein Einfluß der Aufheizgeschwindigkeit auf die Bruttoaktivierungsenergie festgestellt.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1970.021310105
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