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  • 1
    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 Kinetik der Vulkanisation sowie die Vernetzungsdichte von Styrol-Butadien-Kautschukmischungen wurden mit zwei Vulkanisationssystemen, einem wirksamen (EV) und einem konventionellen (CV), untersucht. Ein oberflächenmodifiziertes Silikat mit Boramingruppen (Si—O—B—(NH2)2) wurde als Füllstoff eingesetzt. Unbehandeltes und mit zwei Silanen (γ-Mercaptopropyl-trimethoxysilan und γ-Aminopropyl-triethoxysilan) modifiziertes Silikat wurden zum Vergleich eingesetzt. Die bestenkinetischen Parameter, wie die höchste Vulkanisierungsgeschwindigkeit, die längste Induktionszeit und die kleinste Aktivierungsenergie, wurden für die Mischung mit boraminiertem Silikat erhalten. Die Vernetzungsdichte, die mit dieser Mischung erreicht wurde, ist ähnlich der von mit Silan modifiziertem Silikat erzielten, da wahrscheinlich die Boramingruppen auf der Silikatoberfläche besser verteilt sind. Diese Fakten führen zu wichtigen technologischen Verbesserungen: größere Verarbeitungssicherheit, schnellere Vulkanisierungsgeschwindigkeit und verbesserte physikalische Eigenschaften.
    Notes: Vulcanization kinetics and crosslink density of styrene-butadiene rubber compounds have been studied with two vulcanization systems, an efficient (EV) and a conventional (CV) one. A surface-modified silica with boron-amine groups (Si—O—B—(NH2)2) was employed as filler. Untreated and modified silica with two silanes (γ-mercaptopropyl-trimethoxysilane and γ-aminopropyl-triethoxysilane) have been used as reference.The best kinetic parameters, such as highest vulcanization rate, longest induction time and lowest activation energy, were obtained for the compound with boronaminated silica. The crosslink density, achieved with this compound, is similar to that with silane-modified silica, probably because of the better surface distribution of boron-amine groups on the silica. These facts lead to important technological improvements: better processing safety, faster vulcanization rate and improved physical properties.
    Additional Material: 4 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 217 (1994), S. 107-117 
    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: Das Verhalten von mit primären Boramingruppen modifizierten Silikat-Füllstoffen wurde unter verschiedenen Reaktionsbedingungen untersucht. Der Füllstoff mit den besten Verstärkungseigenschaften wurde eingesetzt, um zwei unterschiedliche Vulkanisationssysteme zu vergleichen: ein wirksames Vulkanisationsverfahren (EV), das nach ISO als Methode zur Untersuchung des Verstärkungsverhaltens neuer Silikate empfohlen wird, sowie ein konventionelles Verfahren. Die besten Ergebnisse werden mit Silikat erhalten, welches 3 h bei 500°C behandelt wurde; unter diesen Bedingungen werden die meisten der primären Boramingruppen fixiert. Die Eigenschaften des nach dem EV-Verfahren modifizierten Silikats ähneln denen von mit Silan modifizierten Silikaten und sind in einigen Fallen besser als jene, welche nach dem konventionellen Verfahren erhalten werden. In allen Fallen wird die verstarkende Wirkung von gefällten Silikat-Füllstoffen durch die Boraminbehandlung verbessert.
    Notes: The behaviour of silica fillers modified with primary boron-amine groups has been studied under different reaction conditions. The filler with the best reinforcing properties was used to compare two different vulcanization systems: an efficient vulcanization system, EV, which is the recommended ISO Standards method to study the reinforcing behaviour of new silicas, and a conventional vulcanization system.The results indicate that the best properties are obtained with silica treated for 3 h at 500°C, reaction conditions which fix most of the primary boron-amine groups. Using the EV system, the properties of this modified silica are similar to those of silane-modified silica, and in some cases better than those obtained with a conventional vulcanization system. In all cases, the boron-amination treatment significantly improves the behaviour of precipitated silica as a reinforcing filler.
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 195 (1994), S. 1043-1062 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In an effort to assess the intermolecular interactions between poly(4-hydroxystyrene)IUPAC name: poly(4-vinylphenol). (P4HS) and poly(vinyl acetate) (PVAc), two types of experimental measurements were conducted: volumetric properties and vapor pressures of solutions in a common solvent (probe). The PVT measurements for a 50:50 (w/w) binary polymer mixtures were conducted over a pressure range from 0 to 100 MPa and a temperature range from 350 to 470 K. The vapor pressures of acetone over a series of ternary systems acetone/P4HS/PVAc, and for four intermediate weight ratios PVAc/P4HS, were measured at 298,15 K, 308,15 K and 318,15 K. PVAc and P4HS interact primarily through hydrogen bonding. The probe molecule (acetone) on the other hand interacts also through hydrogen bonding with P4HS. A recent equation-of-state theory of hydrogen bonding has been used to correlate these measurements. Application of the theory was requiring the knowledge of the volumetric behavior of pure P4HS. Extensive PVT measurements for this polymer have also been conducted. The PVT measurements for the polymer mixture were used in order to estimate the hydrogen bonding parameters for the hydroxyl-ester pair. The vapor pressures of the system acetone/P4HS were used in order to estimate the hydrogen bonding parameters of the hydroxyl-carbonyl pair. On the basis of this information the theory was used to predict the vapour pressures of the ternary system. The theoretical predictions are in quantitative agreement with the experiments.
    Additional Material: 8 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 196 (1995), S. 1063-1075 
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The surface properties of methacrylic copolymers with a random distribution of perfluoroalkyl pendent groups were studied by a tensiometric method and were found to depend on the concentration of fluorinated units (2-hydroxy-4,4,5,5,6,6,7,7,8,8,9,9,9-tridecafluorononyl methacrylate (1)), and the nature of the non-fluorinated methacrylic ester (methyl, butyl, stearyl). The surface tensions estimated by various approaches (critical surface tension, geometric and harmonic mean approximations) are very low (11 mN · m-1 〈 y 〈 12 mN · m-1). The surface tension of the copolymers drops drastically when a few percent of fluorinated units are incorporated into the polymeric chain. The wetting hysteresis, observed particularly in the case of water, could be due to the mobility of macromolecular chains at the interface, leading to a reorganization of fluorinated groups in order to minimize the interfacial energy.
    Additional Material: 3 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 22 (1984), S. 2777-2788 
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In contradiction to reports from this and other laboratories, this study reports that the integrated Mayo-Lewis equation, or Meyer-Lowery equation, adequately describes the high-conversion free radical copolymerization of styrene and methylmethacrylate. The copolymerization was monitored by following the changes in the feed composition using NMR, as well as determination of the resulting copolymer compositions by NMR and UV. “Error in all Variables” statistical techniques were used to produce estimates of the reactivity ratios. The reactivity ratios estimated were, from feed composition, NMR, r1 (styrene) = 0.472, r2 = 0.454, from copolymer composition, UV, r1 = 0.497, r2 = 0.464, and NMR, r1 = 0.432, r2 = 0.422.
    Additional Material: 7 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 1413-1429 
    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 model for bulk polymerization of AN is developed. It adequately predicts conversion-time histories and molecular weight development in the temperature range of 40°-80°C with AIBN as initiator. It is shown that this model has predictive powers by simulating nonisothermal conversion-time histories.
    Additional Material: 14 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 1397-1411 
    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 comprehensive experimental investigation is reported of the bulk polymerization of acrylonitrile (AN) to limiting conversion using 2,2′-azobisisobutyronitrile (AIBN) as initiator at 40°, 60°, and 80°C. Molecular weight development was followed by gel permeation chromatography (GPC).
    Additional Material: 18 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 27 (1982), S. 2043-2052 
    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: As a first step in the elucidation of the microstructure of styrene copolymers using ultraviolet spectroscopy, the data available in the literature has been reviewed and reevaluated. It is shown by using simple error propagation analysis that the abnormalities observed in the extinction coefficients of styrene copolymers can be easily attributed to the experimental error. No significant deviations from the linear absorption behavior can be observed at the specific wavelengths reported in the literature (254-269 nm). As a result of this work, a useful set of correlations for the estimation of the copolymer composition have been obtained. These correlations appear to be adequate for copolymers of different microstructure.
    Additional Material: 7 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 21 (1983), S. 841-849 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two polymer solution models have been used to analyze poly(dimethyl siloxane) (PDMS) + alkane and PDMS + ketone systems. The free-volume and nonrandom interaction contributions are studied separately in order to compare the expressions for the local site fractions used in the two models. Predictions of the reduced residual chemical potential and excess volumes are discussed and compared with those found in the literature for these systems.
    Additional Material: 2 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 783-791 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: An expression for local composition which describes nonrandom interactions between unlike molecules in polymer solutions is proposed. This expression makes the nonrandom model compatible with the one-fluid hypothesis and satisfies the limits of randomness when experimental conditions evolve in such a way. Data on several binary systems are studied using this model which represents simultaneously activity and heat-of-mixing data.
    Additional Material: 4 Ill.
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