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  • Polymer and Materials Science  (14)
  • Meteorology and Climatology
  • 1965-1969  (14)
  • 1
    Electronic Resource
    Electronic Resource
    Interfacial polymerization of n-alkyl α-cyanoacrylate homologs (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1617-1623 
    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: The n-alkyl α-cyanoacrylates from methyl through n-octyl exhibit a reverse order of polymerization rate on biological substrates compared to that on water. On water, the lower homologs spread and polymerize rapidly, whereas the higher homologs spread but polymerize slowly. On biological substrates, the lower homologs do not spread or spread slightly and the higher homologs exhibit large spreadabilities and very rapid polymerization rates. Determination of the spreading coefficients for these systems by using the monomers or model compounds confirm the observed spreadabilities. It is proposed that the increased rate of polymerization of the higher homologs on biological substrates may be due to increased catalyst concentrations on these surfaces or to the solubilization of the higher homologs at the interface, making the catalyst sites more available to the monomer. The suggestion is made that if the liquid monomers spread and orient on the substrate and subsequently polymerize, the polymers will maintain the orientation. If such is the case, a technique is available for preparing stereospecific vinyl polymers which may have different spatial configurations depending on the polarity of the liquid substrate upon which they have been allowed to spread and polymerize.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1966.070101101
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  • 2
    Electronic Resource
    Electronic Resource
    Polymer degradation. V. Changes in molecular weight distributions during sonic irradiation of polyisobuteneProd. No. 1470 (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 335-340 
    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: Gel permeation chromatography was used to follow changes in the molecular weight distribution of a polyisobutene, initial Mv = 466,000, during degradation induced by sonic irradiation. Seven samples taken at times of 200-163,500 sec. were studied. In general, a steady decrease in molecular weight was observed, although a bimodal distribution was present after 20,000 sec. irradiation. Various measures of inhomogeneity, Mw/Mn, U, etc., were examined. The function, σn/Mw, where σn is the standard deviation of the number distribution, is considered as a measure of the relative distribution. It is shown to be almost constant throughout the degradation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070110302
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  • 3
    Electronic Resource
    Electronic Resource
    Characterization of block and random ethylene-propylene copolymers by differential thermal analysisPresented in part before the Division of Polymer Chemistry, 148th National Meeting of the American Chemical Society, Chicago, August 30-September 4, 1964. (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 3061-3069 
    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: A group of C14-tagged ethylene and propylene polymers consisting of physical mixtures of homopolymers, block copolymers made up of two homopolymer sequences, and block copolymers made up of several homopolymer segments has been studied by differential thermal analysis (DTA). The effect of randomness in copolymers has also been studied in this set of systems, which contains 0-51 wt.-% ethylene. Block copolymers and physical mixtures have been found to have thermograms with endothermal minima at approximately 138 and 163°C. The ratio of heights of the two minima has been found to be a function of the ethylene and propylene content for mixtures of homopolymers and for block copolymers without randomness. DTA thus provides an analysis for monomer ratios in physical mixtures and in block copolymers of ethylene and propylene. The cooling thermograms of block copolymers have been demonstrated to have two exotherms in all cases where the block ethylene content exceeded 10%; the propylene limit was not fixed. Mixed homopolymers do not exhibit two freezing exotherms. The total heat of fusion of the polymer has been found to be a usable measure of chain randomness and block nature. The conditions for observation of single and multiple transitions have been extended.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1965.070090912
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of tacticity on polypropylene fractionationPart V of a series on “Column Fractionation of Polymers”. Presented in part before the Organic Coatings and Plastics Chemistry Division, 149th Nat'l. Meeting, American Chemical Society,Detroit, April 1965. (1966)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 94 (1966), S. 143-152 
    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 Fraktionierung von Polymeren durch Gradientenelution beruht auf der Abnahme der Löslichkeit mit zunehmendem Molekulargewicht. Diesem Prozeß kann sich jedoch ein Einfluß der Taktizität überlagern. In der vorliegenden Arbeit wird dies für den Fall der Fraktionierung von Polypropylen untersucht. Hierzu werden typische “ataktische” und “isotaktische” Fraktionen verwendet, die sich durch ihre Löslichkeit in n-Heptan unterscheiden. Der Taktizitätsgrad wird an Hand hochaufgelöster PMR-Spektren der Methylenprotonen ermittelt. Eine Eichkurve wird mitgeteilt, die auf Ergebnissen dieser Arbeit und auf Messungen von SATOH und KATO beruht. Die Beziehung wird mit den Spektren aus den Veröffentlichungen von STEHLING und von WOODREY verglichen. Änderungen der Taktizität mit dem Molekulargewicht sind bei den Fraktionen mit niedrigen Molekulargewichten am ausgeprägtesten, und zwar sowohl bei “ataktischen” als auch bei “isotaktischen” Polypropylenen. Die Auswirkung dieser Tatsache auf die scheinbare Molekulargewichtsverteilung wird diskutiert.
    Notes: The basis for gradient-elution fractionation is a regular decrease in solubility with an increase in polymer molecular weight. tacticity, however, can be an overlapping effect in the solvent separation process. In this study, the effect of tacticity in the fractionation of polypropylene has been studied using representative “atactic” and “isotactic” polymers, defined by heptane solubility. Typical and published column techniques have been used. A high resolution proton magnetic resonance analysis of protons in the chain methylene region was used for evaluation of tactic placement. A new tacticity correlation was developed which is based on data obtained here and on PMR results on polypropylene reported by SATOH and KATO. This correlation has been compared to published spectra of STEHLING and of WOODBREY. Changes of tacticity with molecular weight are most prominently observed in the first gradient-elution fractions from both “atactic” and “isotactic” polypropylenes. The implication of these results concerning apparent molecular weights and distributions is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1966.020940116
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  • 5
    Electronic Resource
    Electronic Resource
    Structural characterization of vulcanizates. Part VI. The 2-mercaptobenzothiazole-accelerated natural rubber-sulfur system (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2227-2253 
    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: The crosslinking efficiency of sulfur in the vulcanization of natural rubber in the presence of 2-mercaptobenzothiazole, zinc oxide, and lauric acid has been determined as a function of cure time, cure temperature, and lauric acid concentration. With a low concentration of lauric acid structurally complex networks are formed, which contain 11-19 combined sulfur atoms per chemical crosslink present. The complexity increases with time of vulcanization. With a high lauric acid concentration much simpler networks are formed, which become progressively more simple as reaction proceeds (6 network-combined sulfur atoms per chemical crosslink, decreasing to 2.4 with time). Increasing the cure temperature from 100 to 140°C. reduces the efficiency of crosslinking in both cases. The changes in efficiency are attributed to the influences of the reaction variables (in particular, the concentration of rubber-soluble complexes of the zinc laurate with zinc benzothiazolyl mercaptide) on the structure and subsequent reactions of initially formed polysulfidic crosslinks.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111112
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  • 6
    Electronic Resource
    Electronic Resource
    Structural characterization of vulcanizates. Part VII. The N-cyclohexylbenzothiazole-2-sulfenamide-accelerated natural rubber-sulfur system (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2255-2269 
    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: The crosslinking efficiency of sulfur in the vulcanization system comprising (in parts by weight) natural rubber (100), sulfur (1.5), N-cyclohexylbenzothiazole-2-sulfenamide (2.37), zinc oxide (5), and lauric acid (1-10) is relatively insensitive to the lauric acid concentration and to the temperature of vulcanization (between 100 and 140°C.). The networks formed contain initially 8-11 combined sulfur atoms per chemical crosslink present, but this number falls progressively to about 4 as the reaction proceeds. The results are consistent with the intermediate formation of a rubber-soluble complex of cyclohexylamine with zinc benzothiazolyl mercaptide. This complex is believed to be responsible also for the further slow crosslinking which the vulcanizates undergo on standing at room temperature.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111113
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  • 7
    Electronic Resource
    Electronic Resource
    Structural characterization of vulcanizates. Part VIII. The N-cyclohexylbenzothiazole-2-sulfenamide-accelerated sulfur vulcanization of natural rubber at 140-180°C. and of synthetic cis-1,4-polyisoprene at 140°C (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2271-2283 
    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: Vulcanization of natural rubber at 140°C. with a CBS-accelerated sulfur system of conventional type gives rise to a structurally complex network in which the number of sulfur atoms combined per chemical crosslink present increases from 12 to 21 with increasing reaction time. The complexity of the network increases with increasing temperature of vulcanization. Crosslinking of a purified synthetic cis-1,4-polyisoprene proceeds more slowly and yields a slightly more complex network. Despite this overall similarity the natural rubber vulcanizates exhibit considerably higher tensile strengths.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111114
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  • 8
    Electronic Resource
    Electronic Resource
    Structural characterization of vulcanizates. Part V. Determination of degree of chemical crosslinking of natural rubber gum vulcanizate networks (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2215-2226 
    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: A general treatment is given of the methods to be used in other parts of this series for calculating the degree of chemical crosslinking in natural rubber vulcanizates from stress-strain measurements in extension and from equilibrium volume swelling measurements. Corrections are required for the presence in the vulcanizate of appreciable quantities of particulate solids or soluble diluents and for the introduction of foreign atoms into the rubber network. For this purpose distinction is made between the rubber vulcanizate, the rubber matrix, the rubber network, and the rubber hydrocarbon component of the network. Expressions are derived, in terms of these concepts, for the Money-Rivlin parameter, C1, measured on vulcanizates which have undergone various treatments.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111111
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  • 9
    Electronic Resource
    Electronic Resource
    On the pressure and concentration dependence of the sedimentation coefficientDedicated to Prof. Dr. G. V. SCHULZ on the occasion of his 60th birthday (1965)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 87 (1965), S. 248-257 
    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: Bei der Untersuchung von Polymerlösungen in organischen Lösungsmitteln mit der Ultrazentrifuge muß der Sedimentationkoeffizient für zwei Einflüsse korrigiert werden: für die zunehmende Verdünnung der Lösung auf Grund der Sektorform der Zentrifugenzelle und für die wachsende Dichte und Viskosität des Lösungsmittels durch das effektive Schwerefeld. Diese Korrekturen können 10-30% des Meßwertes betragen. Eine graphische Methode wird vorgeschlagen, die beide Korrekturen ohne zusßatzliche Informationen ermöglicht. In Verbindung mit einem in der Literatur beschriebenen Verfahren ist die gleichzeitige Bestimmung eines Mittelwertes des Molekulargewichts des gelösten Polymeren möglich.
    Notes: In the ultracentrifugation of solutions in organic solvents the sedimentation coefficient has to be corrected for two effects: the increasing dilution of the solution due to the sector shape of the centrifuge cell and the increasing density and viscosity of the solvent caused by the effective field of gravity. The corrections can amount to 10-30% of the measured value. A new graphical method of correcting for both effects without the need for any additional data is described. This technique in combination with established procedure also allows calculation of an average molecular weight of the solute.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1965.020870119
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  • 10
    Electronic Resource
    Electronic Resource
    Viscosity of polystyrene near the glass transition (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 13 (1969), S. 2427-2437 
    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: A quantitative explanation is given for the apparent viscosity increase with increasing capillary shear rate for polystyrene at temperatures approaching the glass transition, Tg. Possible shifts in Tg as a function of the parameters shear rate, frequency, and pressure are interrelated to viscosity changes. Experimentally, the Instron capillary rheometer and the Weissenberg rheogoniometer provided a means for uncoupling the variables for individual consideration. Calculated and experimental data for the apparent viscosity as a function of the given parameters are presented and discussed. The explanation of the apparent viscosity increase in capillary flow can be quantitatively explained through the pressure dependence of Tg. Brief mention is made of the pressure effects on the Bagley and Rabinowitsch corrections normally made in capillary measurements.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1969.070131116
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