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  • 1
    Electronic Resource
    Electronic Resource
    Distribution of plasma membrane rosettes and kinetics of cellulose formation in xylem development of higher plants (1986)
    Springer
    Protoplasma 131 (1986), S. 142-152 
    Details
    ISSN: 1615-6102
    Keywords: Cellulose fibril formation ; Freeze-fracture ; Plasma membrane ; Rosette distribution ; Xylem development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Germ roots of several higher plants—maize (Zea mays), mung bean (Vigna radiata) and cress (Lepidium sativum)—were freeze-fractured without cryoprotection in order to confirm and extend the informations on frequency and distribution of plasma membrane particle complexes with respect to cellulose formation. In all three objects the PF of developing xylem elements showed rosette accumulations in the regions of wall thickenings. The rosette-distribution pattern ranges from random in a young stage, to more grouped in a probable intermediate stage to strictly localized in later stages. The frequency of rosettes increases from stage to stage. In all three objects the EF of developing xylem elements is relatively poor in particles. Observations of “terminal globules” were rare and undistinct. This leads to the assumption that rosettes on the PF and terminal globules on the EF are not part of the same complex. A comparison of the number and distribution of microtubules underlying the xylem wall thickenings with rosette frequency and distribution leads to the conclusion that there seem to be no direct connections between these two structures. Microtubules may be involved in grouping of rosettes, thus indirectly orienting microfibril deposition. Calculations based on the observed rosette frequencies and the amount of wall material formed indicate that in xylem development 1,000 nm elementary fibril per rosette per minute may be formed and that the active phase of one rosette may be about 10 minutes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01285036
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  • 2
    Electronic Resource
    Electronic Resource
    Composition analysis of crosslinked styrene-ethylene dimethacrylate and styrene-divinylbenzene copolymers by Raman spectroscopy (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 3553-3561 
    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 method for the determination of composition and content of pendent double bonds in untreated samples of styrene-ethylene dimethacrylate and styrene-divinylbenzene copolymers from Raman spectra has been developed. By computer treatment of spectra it was shown that Raman spectra are sensitive to the distribution of components in the studied copolymers.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070231211
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  • 3
    Electronic Resource
    Electronic Resource
    High resolution 1H-NMR relaxation study of polyisobutylene in solution (1976)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 14 (1976), S. 1789-1800 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: From the temperature dependence of integrated intensities and from line widths in high-resolution 1H-NMR spectra, the relaxation times T1 and T2 of protons in CH2 and CH3 groups of polyisobutylene in CCl4 solution have been determined. Although the relaxation time T1 of methylene protons is determined mainly by intragroup interactions, intergroup interactions of two methyl groups from each two consecutive monomer units were found to contribute considerably to T1 of methyl protons. The Structure and mobility of polyisobutylene (PIB) molecules in solution is discussed on the basis of the relaxation time data.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1976.180141005
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  • 4
    Electronic Resource
    Electronic Resource
    Structure of the product of polymerization of 2,3-epoxypropyl methacrylate in the presence of porous glassDedicated to Professor Dr. Dr. h. c. Hermann Klare on ocassion of his 70th birthday (1979)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 30 (1979), S. 283-289 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Mittels 1H- und 13C-NMR- sowie Ramanspektren wurde gezeigt, daß die Epoxidgruppe von 2,3-Epoxypropylmeth-acrylat (EPMA) in Gegenwart einer großen Glasoberfläche quantitativ gespalten wird, wobei es zur Bildung von 2,3-Dihydroxypropylmethacrylat und einer Reihe von niedrigmolekularen Substanzen mit Doppelbindungen kommt. Die Polymerisation von EPMA in Gegenwart von porösem Glas liefert Poly(2,3-epoxypropyl-methacrylat). Ein Teil dieses Polymers ist am Glas fest gebunden, wahrscheinlich über die Zerlegungsprodukte des EPMA.
    Notes: From 1H- and 13C-NMR and Raman spectra it was found that by the presence of a large surface of glass, the epoxide group of 2,3-epoxypropyl methacrylate (EPMA) is completely decomposed, yielding 2,3-dihydroxypropyl methacrylate and a number of additional low-molecular-weight products with double bonds. Polymerization of EPMA in the presence of porous glass yields poly(2,3-epoxypropyl methacrylate). Part of this polymer is firmly bound to the glass, probably by means of the decomposition product of EPMA.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1979.010300512
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  • 5
    Electronic Resource
    Electronic Resource
    Multiple-pulse 1H-NMR study of polystyrene gels (1985)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 36 (1985), S. 645-648 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Untersucht wurden 1H-FID- und MW4-Spektren vom mit Ethylendimethacrylat und Divinylbenzen vernetztem und mit CCl4, CDCl3 und Benzen gequollenem Polystyren. Die mit Hilfe von Vielimpulscyclen erreichbaren Linienverschmälerungen werden diskutiert und mit denen der MAR-Technik verglichen. Die Temperaturabhängigkeit der effektiven Relaxationszeit T2eff spiegelt die Dynamik lokaler Segmentprozesse wider.
    Notes: 1H-FID and MW4-pulse spectra of polystyrene crosslinked with ethylene dimethacrylate or divinylbenzene and swollen in CCl4, CDCl3 or benzene, are measured. Line-narrowing effects of multiple-pulse sequences are discussed and compared with those of the MAR-technique. The temperature dependence of the effective relaxation time T2eff reflects the dynamics of local segmental processes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1985.010361201
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  • 6
    Electronic Resource
    Electronic Resource
    Separation and characterization of stereoisomers of 2,4,6-triphenylheptane (1966)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 4 (1966), S. 645-651 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1966.110040912
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of association of stereoregular poly(methyl-methacrylate) in solution upon integrated intensities of HR-NMR spectra (1974)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 12 (1974), S. 349-353 
    Details
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1974.130120608
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  • 8
    Electronic Resource
    Electronic Resource
    Nmr spectra of the meso and d,l-isomers of dimethylglutarate and 2,4-diphenylpentane (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 3 (1965), S. 213-219 
    Details
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.110030312
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  • 9
    Electronic Resource
    Electronic Resource
    NMR spectroscopic, osmometric, and viscometric study of association of syndiotactic poly(methyl methacrylate) in dilute solutions (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 20 (1982), S. 1623-1632 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Association of syndiotactic (s) poly(methyl methacrylates) (PMMAs) in toluene, benzene, and acetonitrile has been studied by NMR spectroscopy, osmometry, and viscometry. It was found that in solutions of highly syndiotactic PMMA in toluene, most of the polymer exists in the associated state. Association takes place by means of stereospecific intermolecular and intramolecular interactions of long parallel syndiotactic sequences. The minimum length of syndiotactic sequences necessary for association of s-PMMA in toluene is 7-8 monomer units. Viscosity data indicate that in dilute solutions the associated structures appear as large formations which do not have the character of compact particles. The formation of the aggregates of PMMA is a relatively slow process. A model of the structure of the aggregates of s-PMMA in toluene is proposed. As compared with that in toluene, the tendency to aggregation in benzene and acetonitrile is negligible. Integral parameters currently used for the characterization of polymer-solvent interaction, like “good” or θ solvent, are not suitable for predicting the tendency of s-PMMA to aggregation. The formation of aggregates evidently has some connection with the effect of the solvent upon the conformational structure of syndiotactic sequences.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.180200911
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  • 10
    Electronic Resource
    Electronic Resource
    Study of ordered structures of syndiotactic poly(methyl methacrylate) in solution and in the solid state (1984)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 22 (1984), S. 617-635 
    Details
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: From analysis of infrared spectra it was found that in syndiotactic (s) poly(methyl methacrylate) (PMMA) in solution, long s sequences contain an increased population of diads with a skeletal conformation tt (in the staggered approximation). Self-aggregation of s-PMMA in solution leads to a further increase of the fraction of long s sequences in the extended chain conformation, and to an ordering of easter groups. When solid s-PMMA is isolated from a solution in which it exists in the aggregated state, these characteristics are preserved in the solid. The polymer appears partially crystalline by x-ray scattering, and it exhibits fibrillar morphology under the electron microscope. Ordered structures of s-PMMA melt at temperatures about 150°C, while the presence of residual solvent decreases the temperature of melting. Solid s-PMMA obtained from solutions in which aggregation of the polymer does not take place, like s-PMMA which did not come into contact with solvent, contains a higher proportion of syndiotactic diads with a skeletal conformation tg; these samples are amorphous and morphologically structureless. Analogies between the structure of ordered s-PMMA and the structure of the PMMA stereocomplex are also discussed.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1984.180220406
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