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  • Wiley-Blackwell  (13)
  • 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
    Electronic Resource
    Electronic Resource
    Mutual correlations between parameters characterizing the miscibility, structure and mechanical properties of polymer blends (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 199 (1992), S. 87-101 
    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: Aus Polymeren mit unterschiedlichen Polaritäten wurden Polymermischungen hergestellt, wobei der gesamte Zusammensetzungsbereich erfafßt wurde. Die mechanischen Eigenschaften wurden durch Zugmessungen charakterisiert. Die Oberflächen- und die Grenzflächeneigenschaften wurden gemessen und berechnet, und die den Grad der Mischbarkeit kennzeichnenden Parameter wurden bestimmt. Da sowohl der Mischbarkeitsgrad als auch die Morphologie von der Grenzflächenspannung beeinflufßt werden, ist letztere als die mit den mechanischen Eigenschaften und den Polymer/Polymer-Wechselwirkungen in Polymermischungen am engsten korrelierte Größe zu betrachten.
    Notes: Polymer blends were prepared in the whole composition range using polymers of different polarity. Mechanical properties were characterized by tensile measurements. Surface and interfacial properties were measured and calculated and parameters characterizing the miscibility were determined. A correlation was found between the yield stress and the thermodynamic quantities characterizing the degree of miscibility. Since both the degree of miscibility and morphology are influenced by the interfacial tension, it can be regarded as the best candidate to correlate polymer/polymer interaction and mechanical properties in polymer blends.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.051990108
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  • 3
    Electronic Resource
    Electronic Resource
    Blends of polycarbonate with poly(methyl methacrylate): Miscibility, phase continuity, and interfacial adhesion (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 886-893 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) concurrently show that polycarbonate (PC)/poly(methyl methacrylate) (PMMA) blends have a two-phase structure. The differences between the Tgs of parent polymers and the Tgs of conjugate phases, determined by both DMTA and DSC, indicate a limited miscibility of components and allow the approximate composition of conjugate phases to be calculated. The Flory-Huggins interaction parameter calculated by using these data assumes values about 0.035 ± 0.010. Phase inversion occurs in an interval close to the 50/50 composition, though the molar masses and melt viscosities of the polymers were rather different. Partial miscibility of components ensures interfacial adhesion capable of sustaining the stress transfer between phases up to fracture. Yield stress of the blends is very close to values foreseen by the rule of mixtures. A specific feature of the blends studied is that the addition of 10 to 20 vol% of PMMA to PC increases the strain at break and work to fracture, which are rather low for the PC used. The enhanced capability of the blends to absorb mechanical energy is probably linked to plastic deformation of the dispersed PMMA.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321308
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  • 4
    Electronic Resource
    Electronic Resource
    Comparison of dynamic and static degradation of poly(vinyl chloride) (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 2615-2623 
    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 thermal degradation of PVC was measured under dynamic and static conditions. The UV and IR spectra, as well as the molecular weight distribution of the PVC samples, taken after different time intervals were measured. It was established that during the dynamic PVC degradation, performed in a mixing chamber, two stages with different degradation rates can be distinguished both in extinction and torque vs. time curves. While oxygen does not, dissolved HCl does play an important role in the dynamic degradation: HCl steps into reaction with the formed polyenes and has a catalytic action. The chemical degradation, particularly the crosslinking, produces the changes in the rheological behavior of the material. Results were compared with those obtained under static conditions in argon, air, and HCl atmosphere.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1982.070270730
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  • 5
    Electronic Resource
    Electronic Resource
    Polypropylene composites. II: Structure-property relationships in two- and three-component polypropylene composites (1992)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 32 (1992), S. 641-648 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Two- and three-component polypropylene (PP) blends and composites were prepared to study their structure/property relationships. Butadiene-styrene (BDS) copolymers of low compatibility formed large particles of poor adhesion in PP resulting in inferior mechanical properties. Better miscibility of ethylene-propylene-diene (EPDM) elastomer results in more finely dispersed particles and the experimental results indicate a transition to an interpenetrating network (IPN)- like structure with increasing elastomer content. Effective impact modification can be achieved only with EPDM elastomers of sufficient miscibility. Mutual wettability and adhesion of the components determine the structure and properties in PP/elastomer/filler systems. Modification of PP by acrylic acid grafting promotes PP/filler adhesion which, in turn, results in the separate dispersion of the components. In an unmodified PP matrix, a significant amount of the filler is encapsulated by the elastomer. At low filler content, better low temperature impact strength is achieved in the case of separately dispersed components, while encapsulation is more advantageous at high filling grades.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760321002
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  • 6
    Electronic Resource
    Electronic Resource
    Polypropylene composites. III: Chemical modification of the interphase and its influence on the properties of PP/mica composites (1994)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 34 (1994), S. 485-492 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 surface treatment technology was developed for PP/mica composites that produces a diffuse interlayer with excellent adhesion between the components. The interlayer is created by the silane treatment of the filler and the chemical modification of the polymer components, and its polarity gradually decreases from the surface of the filler to the matrix. Properties of the composites depend on the characteristics of the interphase. With changing chemical composition, the characteristics of the interphase change from a thin, rigid layer to a more diffuse, elastic one. Properties of the composites change accordingly, optimum properties are achieved with a thick interlayer ensuring good stress transfer, strength, hardness, acceptable impact properties, and low mold shrinkage.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760340605
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  • 7
    Electronic Resource
    Electronic Resource
    Impact testing of polypropylene blends and comosites (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 1962-1971 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Polypropylene (PP) composites containing 0.30 vol% of talc filler, in addtion to blends modified with an ethylene-propylene copolymer (EPR) elastomer were prepared and their fracture resistance was determined by the standard Ixod impact test and by a fracture mechanics technique. Effects of composition, type of modification, specimen size, and temperature were studied. The validity of linear elastic freacture mechanics (LEFM) conditions were checked: It was shown that under the conditions applied they can be satisfied even twith specimens of reasonable size (4 × 10 × 80 mm) prepared by conventional processing techniques. Calculations of minimum specimen thickness must be carried out, with material properties obtained under the conditions of impact. For heterogeneous blends and composites yield stress should be corrected for the effect of decreasing load-bearing cross section. Linearity of the fracture energy (U) vs. BDφ or U vs. B(D - a) plots is not a proof for either elastic of plastic fracture. The composition dependence of fracture properties proved to be practicaly independent of specimen size, temperature, or measurement technique.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760352408
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  • 8
    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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  • 9
    Electronic Resource
    Electronic Resource
    Untersuchung der Gelierung von Suspensions-PVC (1979)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 81 (1979), S. 109-123 
    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: Examining of the plasticiser absorption of suspension PVC powders has been established that its mechanism is similar but its kinetics are different for S-PVC powders of different morphology, which results in different particle size distributions of the produced dry-blends.As a result of the thermomechanical testing of these dry-blends the conclusion has been drawn that the melt viscosity is a linear function of PVC/plasticiser ratio in a given temperature range. The melt viscosity decrease of the compounds made from powders of different Fikentscher K values reaches a limit as the temperature increases. The limiting value is about 190°C, it depends on the molecular weight and it is roughly proportional with the second power of K value.The properties of the product change significantly during thermomechanical processing. The transparency and the tensile strength referred to the tearing cross section (relative tensile strength) have been found to be the most characteristic among the properties. Regarding the values of the relative tensile strength it has been assumed that the plasticiser makes possible the intense orientation of the PVC matrix even at room temperature. It has been established that the value of the relative tensile strength is a linear function of PVC/plasticiser volume fraction.It has been shown by the experiments that the processes respectively terms of plastification and gelisation can be separated. The first seem to take place in segmental and the second in supramolekular dimensions.
    Notes: Die Untersuchung der Weichmacheraufnahme von Suspensions-PVC Pulvern verschiedener Morphologie ergab, daß deren Weichmacheraufnahmemechanismus gleich, ihre Kinetik jedoch unterschiedlich ist, was in der Korngrößenverteilung der Trockenmischung bedeutende Unterschiede verursacht.Bei der Untersuchung der thermomechanischen Bearbeitung der Trockenmischung wurde festgestellt, daß in gewissen Temperaturbereichen die Schmelzviskosität eine lineare Funktion des Volumenverhältnisses des PVC-Weichmachers ist. Die Abnahme der Schmelzviskositäten mit der Temperatur der aus Pulvern verschiedenen K-Wertes hergestellten Mischungen erreicht um 190°C einen Grenzwert, der molekulargewichtsabhängig und annähernd dem Quadrat des K-Wertes proportional ist.Während der thermomechanischen Bearbeitung verändern sich die Produkteigenschaften bedeutend, wobei die Transparenz und die auf den Reißquerschnitt bezogene Reißfestigkeit (relative Reißfestigkeit) am charakteristischsten ist. Berücksichtigt man die Größe der relativen Reißfestigkeit, stellt man fest, daß der Weichmacher eine erhöhte Orientierung der PVC-Matrix auch bei Raumtemperatur ermöglicht. Ferner wurde festgestellt, daß-die relative Reißfestigkeit eine lineare Funktion des Volumenbruches von PVC ist.Experimentell wurde nachgewisen, daß die Vorgänge bzw. Begriffe Weichmachung und Gelierung zu trennen sind. Es scheint, daß der erstere im segmentalen, der letztere im molekularen bzw. supramolekularen Bereich vor sich geht.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1979.050810110
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  • 10
    Electronic Resource
    Electronic Resource
    Ternary composites of polypropylene, elastomer, and filler: Analysis of phase structure formation (1990)
    Brookfield, Conn. : Wiley-Blackwell
    Polymer Composites 11 (1990), S. 98-104 
    Details
    ISSN: 0272-8397
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Investigation of the morphology and properties of ternary composites of polypropylene, ethylene-propylene-diene terpolymer, and filler has shown that in such systems two kinds of structures can be formed: separate dispersion of the components or encapsulation of the filler by the elastomer. A thermodynamic analysis of the two structures revealed that encapsulation is the thermodynamically favored process. The final structure is determined by the stability of the encapsulated units, which depends on the relative magnitude of adhesion and shear forces. The former depends on the reversible work of adhesion and on the particle size of the filler, while the latter depends on the viscosity and shear rate. Surface treatment of the filler decreases the work of adhesion, resulting in extensive de-encapsulation. The developed tentative explanation is in agreement with the observed phenomena and experimental results.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pc.750110205
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