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  • 1
    Electronic Resource
    Electronic Resource
    Einfluß von gleitmitteln auf die rheologischen eigenschaften von PVC-mischungen (1979)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 79 (1979), S. 107-124 
    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 significance of lubricants is emphasized by the growing number of publications on this field. However, most of the authors compare the effect of the different lubricant types at the same concentration. But the rightness of this kind of comparison is questionable because the rheological characteristics of PVC compounds change sharply at the compatibility. Relatively little attention is paid to the processes taking place before the forming of the melt phase (powder blending) during PVC processing as well.From the results of the measurements made on a capillary viscosimeter and on a Brabender-plastograph the conclusion can be drawn that the comparison of lubricants is better in the same state (at the compatibility) than at the same concentration. The processes taking place in the mixing head of a Brabender-plastograph can be divided into three stages (powderblending, fusion, melt flow) and these are influenced differently by lubricants. The results of the measurements made on the capillary viscosimeter and the plastograph show a very good agreement in the melt flow state in view of lubricant effectivity.
    Notes: Die Bedeutung von Gleitmitteln bei PVC-Mischungen ist aus einer zunehmenden Zahl von Veröffentlichungen auf diesem Gebiet zu erkennen. Die Mehrzahl der Autoren vergleicht jedoch die Wirkung der einzelnen Gleitmitteltypen bei gleicher Konzentration. Die Richtigkeit dieser Methode ist fraglich, da sich die rheologischen Eigenschaften der PVC-Mischungen sprungartig verändern. Es wurde verhältnismäßig wenig Interesse den Vorgangen vor der Bildung der Schmelzphase (Pulverschmierung) während der Verarbeitung von PVC gewidmet.Aus den Messungen mit Kapillarviskosimeter und Plastograph kann der SchluB gezogen werden, daß der Vergleich im gleichen Zustand (bei Verträglichkeit) dem bei gleicher Konzentration vorzuziehen ist. Die Vorgänge in der Knetkammer des Brabender-Plastographen können in drei Teilvorgänge (Pulvermischung, Gelierung, Schmelzfluß) unterteilt werden, die durch die Gleitmittel verschieden beeinflußt werden. Die MeRergebnisse mit dem Kapillarviskosimeter stimmen im Schmelzzustand hinsichtlich der Gleitmittelwirkung gut überein.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1979.050790109
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  • 2
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    Nanophase separation in segmented polyurethane elastomers: Effect of specific interactions on structure and properties (2008)
    Elsevier
    Details
    Publication Date: 2008-08-01
    Print ISSN: 0014-3057
    Electronic ISSN: 1873-1945
    Topics: Chemistry and Pharmacology , Physics
    Published by Elsevier
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    PAPER CURRENT
  • 3
    Electronic Resource
    Electronic Resource
    Electron paramagnetic resonance investigation of orientation produced by mechanical processing in the fillers of polymer composites (1985)
    s.l. : American Chemical Society
    Macromolecules 18 (1985), S. 918-923 
    Details
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ma00147a017
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  • 4
    Electronic Resource
    Electronic Resource
    Lewis acid initiated melt reactions of polystyrene and EPDM rubber (1984)
    Springer
    Polymer bulletin 12 (1984), S. 157-163 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary In order to obtain high impact polystyrene (PS), experiments have been performed on coupling of EPDM rubber and PS in the mixing chamber of a HAAKE plastograph. Lewis acids were added to the melt and the torque increase observed by their addition proved that chemical reactions take place in the system. During the reaction, the rubber proved to be more active, it became crosslinked and/or it was coupled with the PS molecules. Only a small fraction of the PS present coupled to the rubber molecules. No significant degradation process could be detected. Mechanical properties (tensile modulus and strength) improved during the reaction. This can be interpreted by the increased solubility of the coupled rubber molecules in the continuous PS phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00263339
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  • 5
    Electronic Resource
    Electronic Resource
    A new correlation between molecular parameters and physical properties of chlorobutyl rubbers grafted with polystyrene branches (1981)
    Springer
    Polymer bulletin 4 (1981), S. 437-443 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary A series of chlorobutyl rubbers grafted with polystyrene branches have been prepared and backbone length, branch density and segment lengths between branches were calculated from the overall graft composition, number average molecular weight, and branch molecular weight. Analysis of the deformation process revealed unexpected correlations between the molecular parameters and tensile properties of the graft: the tensile strength is directly, and the elongation at break inversely proportional to the ratio of branch molecular weight to the molecular weight of segments between the branches. Further, the tensile strength and elongation at break are proportional to the molecular weight of the backbone. A general correlation was found between the backbone molecular weight and the specific breaking energy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255698
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  • 6
    Electronic Resource
    Electronic Resource
    Cationic reactions in the melt (1981)
    Springer
    Polymer bulletin 5 (1981), S. 469-476 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effect of Lewis acids of different acidities, i.e., AlCl3 and Bu2SnCl2, on polystyrene melt has been investigated using the mixing chamber of a Brabender Plastograph at 180°C. The torque was monitored as a function of time and molecular weights of periodically withdrawn samples were determined. The structure of select samples has-been analyzed by 1H-NMR spectroscopy. A sequence of complex physical and chemical transformations has been identified. The addition of Lewis acids to polystyrene melts causes an immediate drastic decrease in the torque due to rapid partial polymer degradation which is followed by homogenization and a slower degradation phase. There is evidence for the formation and accumulation of unsaturation during degradation. Cationic reactions induced by the Lewis acids readily explain the observed sequence of chemical transformations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255985
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  • 7
    Electronic Resource
    Electronic Resource
    Cationic reactions in the melt (1982)
    Springer
    Polymer bulletin 6 (1982), S. 327-333 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The effect of Lewis acids on various ethylene-propylene co- and terpolymers has been investigated in the mixing chamber of a Brabender Plastograph at 180°C. Fast degradation of the polymers was observed upon the addition of Lewis acids. Terpolymers containing unsaturations undergo crosslinking: the structure of the third monomer (diene) determines the rate of crosslinking and the characteristics of the crosslinked materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255406
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  • 8
    Electronic Resource
    Electronic Resource
    Cationic reactions in the melt (1982)
    Springer
    Polymer bulletin 6 (1982), S. 335-341 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Reactions in the melt between polystyrene and ethylene propylene co- and terpolymers were studied in the presence of anhydrous AlCl3 using the mixing chamber of a Brabender Plastograph as the reactor. Various concurrent reactions have been identified, i.e., grafting, degradation, crosslinking, etc., the rates of which depend on the nature of the polymers and of the AlCl3 added. Grafting is extensive, 40–50%, and the composition of the grafts is close to that of the charge.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00255407
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  • 9
    Electronic Resource
    Electronic Resource
    Mechanical damping in instrumented impact testing (1997)
    Springer
    Journal of materials science 32 (1997), S. 6601-6608 
    Details
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Instrumented impact testing is an effective tool for the study of high-speed fracture of polymeric materials. The evaluation of force signals is usually impeded by dynamic effects. These can be compensated by mechanical damping which, however, leads to additional energy absorption. A model and a technique were developed for the determination of the viscoelastic properties of the damper. Correction of the force versus deflection traces obtained in the instrumented impact test is carried out automatically during the evaluation of the test. Unbiased force versus deflection correlations are recovered and the most important fracture parameters are determined. Comparison of different correction techniques has shown the validity of the method. The agreement between Kc values calculated from the maximum force and fracture energy proved to be excellent. The developed technique greatly facilitates the evaluation of instrumented impact tests and increases the reliability of the measurement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018635916466
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  • 10
    Electronic Resource
    Electronic Resource
    Oxidation of polyethylene in closed mixing chamber (1987)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 150 (1987), S. 89-111 
    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: Der Abbau eines handelsüblichen Polyethylens niedriger Dichte wurde unter dynamischen Verhältnissen untersucht, die den Verarbeitungsprozeß simulierten. Sowohl die dynamische Oxidation über 140°C als auch die statische Oxidation bei niedrigem Sauerstoffdruck sind stark diffusionskontrolliert. Während des Prozesses konkurrieren Kettenspaltung und Vernetzung (hauptsächlich C - C Bindungen) miteinander. In der Anfangsphase des Abbaus überwiegen die Hydroperoxidgruppen. Während ihr Anteil aber schnell abnimmt, nimmt der der Oxygruppen zu und wird dominant.Unter 140°C ist der Prozeß ähnlich der statischen Oxidation bei höherem Sauerstoffdruck, die Diffusionskontrolle spielt aber noch immer eine Rolle. Eine geringe änderung des Molekulargewichts ist zu beobachten. Während des Prozesses dominieren die Hydroperoxide. Während des Knetens ist ihr Anteil unter den gebildeten funktionellen Gruppen nahezu konstant. Der Einfluß der mechanischen Beanspruchung ist unbedeutend.Die Steigerung der Knetgeschwindigkeit beschleunigt die Abbauprozesse. Je höher die totale in das LDPE eingebaute Menge des Sauerstoffes ist, desto niedriger ist die restliche Oxidationsstabilität.
    Notes: The degradation of commercial LDPE was studied under dynamic conditions which simulate the processing. Dynamic oxidation above 140°C is similar to static oxidation under low oxygen pressure both having strong diffusion control. Fragmentation and crosslinking (mainly C—C bonds) compete in the process. The hydroperoxides predominate at the beginning of the mixing. Their quantity rapidly decreases while that of oxo groups increases and becomes predominant.Below 140°C, the conditions are resembling to static oxidation performed under higher oxygen pressure but the process is still somewhat diffusion controlled. The change in the molecular mass is not considerable in the process. The hydroperoxides predominate among the functional groups formed. Their ratio is constant during mixing. The effect of mechanical stress is not considerable.An increase in the mixing speed resulted in an increase in the rate of the processes studied above.The higher the total amount of oxygen incorporated in the PE, the smaller is the remaining oxidative stability.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1987.051500108
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