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  • 1
    Electronic Resource
    Electronic Resource
    Strain-induced crystallisation and miscibility behaviour of hydrogenated nitrile rubbersPaper presented at the meeting of the GDCh-Fachgruppe “Makromolekulare Chemie” on “Kautschukelastische Polymersysteme” in Bad Nauheim (Germany), March 30-31, 1992. (1992)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 202 (1992), S. 143-158 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: HNBR rubbers, which are made by selective hydrogenation of the olefinic bonds of NBR rubbers, have been developed, because they show improved resistance towards heat and chemicals. In this study, two other properties are discussed that arise from the fact that HNBR rubbers are fairly alternating copolymers of unpolar butylene and polar acrylonitrile units: At intermediate compostions, HNBR rubbers form homogeneous blends with PVC, and near the symmetric composition they exhibit strain-induced crystallisation. The thermal transitions of the HNBR rubbers and their miscibility with PVC were analyzed, as well as the crystallisation and the stress-strain behaviour of a HNBR of symmetric composition.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1992.052020109
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  • 2
    Electronic Resource
    Electronic Resource
    Mutual miscibility of chlorinated hydrocarbon polymers derived from polyethylene and polyvinylchlorideDedicated to Prof. Dr. Dr. h. c. H. Hellmann on the occasion of his 75th birthday (1989)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 171 (1989), S. 53-63 
    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: Untersucht wurde die Verträglichkeit von polymeren Chlorkohlenwasserstoffen mit verschiedener Comonomersequenzordnung. Eine erste Copolymerenserie (“PVCx”) wurde durch Reduktion von Polyvinylchorid hergestellt, eine zweite Serie (“PECx”) durch Chlorieren von Polyethylen. Die Polymer-Legierungen PECx/PECy, PVCx/PVCy und PVCx/PECy wurden bei 30°C und 110°C mit einer Lösungsfilmmethode analysiert. Im System PECx/PECy nimmt die Mischbarkeit mit steigendem Chlorgehalt der Copolymeren stetig zu. Bei den Systemen PVCx/PVCy und PVCx/PECy zeigt sich im Bereich um x = 1 eine erhöhte Tendenz zur Phasenseparation, die auf die bessere Comonomersequenzordnung der Copolymeren PVCx zurückzuführen ist. Im letzteren System ist diese Tendenz so stark, daß Polyvinylchlorid (PVCx=1) sogar mit dem chlorierten Polyethylen PECx=1, das die gleiche Bruttozusammensetzung hat, nicht mischbar ist.
    Notes: The compatibility of chlorinated hydrocarbon polymers of two different comonomer sequence orders was investigated. One series of copolymers (“PVCx”) was prepared via reduction of polyvinylchloride, the other (“PECx”) via chlorination of polyethylene in solution. The blends PECx/PECy, PVCx/PVCy and PVCx/PECy were analyzed with a film casting method at 30°C and 110°C. Miscibility increases in the system PECx/PECy steadily in the direction of increasing chlorine content. Due to the comonomer sequence order in the copolymers PVCx the systems PVCx/PVCy and PVCx/PECy show in the range around x = 1 an extra effect favouring phase separation. In the latter system this effect is so strong that polyvinylchloride (PVCx = 1) is even incompatible with the chlorinated polyethylene PECx=1 although both have the same overall composition.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1989.051710104
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  • 3
    Electronic Resource
    Electronic Resource
    Mechanical properties, molecular motions and density fluctuations in polymer-additive mixtures (1985)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 12 (1985), S. 189-214 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Two effects are of outstanding importance for the mechanical behaviour of polymer-additive mixtures, (a) the plasticizer effect and (b) an effect, which we shall refer to as the “β-suppression” effect: Additives can suppress the secondary (β-) relaxations of the polymer. The β-suppression effect is studied on a number of polymers and additives (dynamic mechanical and dielectric measurements), the molecular motions involved are characterized (2H-NMR spectroscopy) and the thermal density fluctuations are measured (SAXS experiments). A model to explain the effect in terms of the free volume fluctuations is presented.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1985.020121985117
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of non-mesogenic comonomers on the phase behaviour, the structure and the miscibility of side chain liquid-crystalline polymersDedicated to Prof. Dr. Milan Lazár on the occasion of his 65th birthday (1993)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 2349-2359 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The phase behaviour of methacrylic side chain liquid-crystalline (LC) copolymers, with a spacer-decoupled mesogen in one comonomer and a methyl (MMA) or stearyla (SMA) substituent in the other comonomer, was studied. The mesogen is of the phenyl benzoate type and has a methoxy end group. The LC homopolymer (PLC) has a smectic and a nematic phase. The comonomers MMA and SMA destabilize the LC phase. This effect is compared to the destabilisation caused by end groups in oligomers of PLC. The SMA side chains crystallize so that the SMA copolymers assume a smectic-crystalline bilayer structure. Finally, it is shown that the order of the copolymers affects their mutual miscibility.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1993.021940818
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  • 5
    Electronic Resource
    Electronic Resource
    Morphologies of mechanically mixed amorphous blends before and after annealing (1995)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 35 (1995), S. 693-702 
    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: The morphologies of amorphous polymer blends produced by extrusion were investigated by transmission electron microscopy. Polymers with similar viscosities, i.e. poly(methyl methacrylate) (PMMA), polystyrene (PS), and random copolymers P(SxMMA1 - x) were mixed pairwise, in different compositions. Finely dispersed phase structures were produced in the blends, with domains in the submicron range. The structure patterns were considerably perturbed by the stress fields in the extruder. Domain-matrix and co-continuous morphologies were obtained, in a distribution controlled mainly by the viscosity ratio. Annealing after extrusion led to structure coarsening, whereby the patterns were changed until a steady state was established. Sometimes, matrix inversion was observed.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760350809
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  • 6
    Electronic Resource
    Electronic Resource
    Tensile strength of thermoplastic blends and compositesDedicated to Prof. Dr. D. Braun on the occasion of his 60th birthday (1991)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 185 (1991), S. 87-96 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Failure of purely thermoplastic blends has so far, in contrast to that of thermoplastic-elastomeric blends, not been studied extensively. In this investigation, the tensile strength of the brittle thermoplastics polymethylmethacrylate and polystyrene, of their random copolymers, their blends, and also of blends of polymethylmethacrylate with the copolymers was measured. The polymers behave all mechanically similarly, but the blends assume all degrees of miscibility and coarseness of phase morphology. For comparison with the blends, also macroscopic composites were tested.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1991.051850109
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  • 7
    Electronic Resource
    Electronic Resource
    Diffusion after chain fragmentation in the glassy state: A SANS studyDedicated to Prof. Dr. E. W. Fischer on the occasion of his 60th birthday. (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 893-905 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A new method to measure the extremely slow chain diffusion in polymer systems at and below the glass transition temperature is proposed. It requires polymers that can be fragmented in a well-defined manner in the glassy state. The idea is first to split all chains, while their conformations are frozen in, and then to measure at some higher temperature the diffusion of the chain fragments by small-angle neutron scattering. The structure factor changes in the course of the fragment diffusion from that of the initial long chains to that of the uncorrelated fragments. Preliminary results from experiments on blends of thermosensitive copolycarbonates and tetramethylpolycarbonate are presented. They demonstrate the viability of the technique.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1990.090280607
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  • 8
    Electronic Resource
    Electronic Resource
    Miscibility of poly (styrene-co-methylmethacrylate)s differing in composition (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 1309-1326 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The mutual miscibility of random poly (styrene-co-methylmethacrylate)s with different compositions but a constant molecular weight of Mw ≅ 150,000 was studied at room temperature and at 180°C. Compatibility was analyzed with films cast from solutions with different solvents. The reliability of the analytical technique is discussed. The miscibility windows {x, yx}, which define the limits of miscibility of the blends of a given copolymer P (SxMMA1-x) with other copolymers P (SyMMA1-y), were determined for all x. The widths |x - yx| of these windows are, contrary to the predictions of the Flory-Huggins model, different for yx 〉 x and yx 〉 x, and depend strongly on x. Miscibility is better for blends with a high MMA content. The windows are markedly wider at room temperature. Many blends are, therefore, “semicompatible,” i.e., have a critical point of the LCST type between room temperature and 180°C.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1990.090280809
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  • 9
    Electronic Resource
    Electronic Resource
    Fragmentation of polycarbonate macroinitiators in solution and in the bulk state (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 2165-2182 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The diphenylethane initiator 3,4-diethyl-3,4-(p-methoxyphenyl)-hexane (T-OCH3) was synthesized. By cocondensation of bisphenol A or C and the bisphenol derivative (“T”) of T-OCH3 with phosgene, polycarbonate macroinitiators PC(TxA1-x) and PC(TxC1-x) with different compositions x were made. The thermal fragmentation of T-OCH3 and the copolycarbonates was investigated with and without a radical scavenger both in solution and in the bulk state. The primary dissociation of T-OCH3 is a monomolecular Arrhenius process with a characteristic temperature of T* (τ = 1h) = 140°C (τ: average life time of the intact molecule). When the radicals are not intercepted, the dissociation is excessively reverted by radical recombination, which raises T* to T* = 163°C. The reaction ends then exclusively in radical disproportionation. The chain fragmentation of the copolycarbonates is of the type of a random decondensation. The counits CT dissociate in solution almost exactly like T-OCH3. In the highly viscous bulk state, the reaction proceeds in matrix cages, which have a stabilizing effect, so that T* is increased to T* = 170°C. These copolycarbonates are model polymers for a novel method to study the hitherto unmeasurably slow chain diffusion processes in polymers near the glass transition temperature.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1990.090281201
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  • 10
    Electronic Resource
    Electronic Resource
    Chain fragmentation under liquid-state and solid-state conditions (1992)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 30 (1992), S. 203-213 
    Details
    ISSN: 0887-6266
    Keywords: degradation, thermal, of copolycarbonates and their blends ; glassy polymers, thermal chain fragmentation in liquid and solid states ; copolycarbonates, pure and in blends, chain fragmentation in ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Thermally Activated fragmentation of copolycarbonates PC(TxA1-x) of bisphenol A (unit CA) and the Heat-sensitive diol 1,1,2,2-tetraethyl-1,2-di-(p-hydroxy) phenylethane (unit CT) was studied in the bulk, i.e., in the pure copolymers and in their blends with the polycarbonates of bisphenol A (PCA) or tetramethyl bisphenol A (TMPC). Fragmentation proceeds via dissociation followed by disproportionation at the central C—C bond of the unit CT. The reaction has rates that are convenient to study near the glass transition temperature. The “chemical” time constants τ for the entire reaction and τ2 for the disproportionation step compete with the “physical” time constants δα for segmental motion and δq for fragment diffusion. A cage effect is observed below τ2 = δα and effects of delayed matrix response below τ = δα and τ = δq. Owing to the two latter effects, parameters such as the glass transition temperature and the structure factor of concentration fluctuations do not respond primarily to the fragmentation, but rather to subsequent relaxation and diffusion processes in the polymer matrix.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1992.090300209
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