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  • 11
    Electronic Resource
    Electronic Resource
    Studies in addition polymerization in mixed solvent system part VI. Chain transfer of aromatic amines in the polymerization of methyl methacrylate (1971)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 149 (1971), S. 243-251 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Kettenübertragungskonstanten von aromatischen Aminen bei der Polymerisation von Methacrylsäuremethylester mit Benzol als Verdünnungsmittel (mixed-solvent method) wurden bestimmt. Die Übertragungskonstanten nehmen in folgender Reihe ab: Anilin 〈 N-Methylanilin 〈 N-Dimethylanilin. Die Kettenübertragungsfähigkeit der Amine wird auf Grund einer polaren Struktur im Übergangszustand erklärt. Eine Substitution, welche die Elektronenabgabe des Amino-Stickstoffs fördert, gibt eine größere Übertragungsfähigkeit. Die durch die Amine bedingte Abnahme der Polymerisationsgeschwindigkeit ist von der gleichen Ordnung wie jene der Kettenübertragungsfähigkeit und wird auf Grund einer Hyperkonjugation erklärt. Die Bestimmung der Aminoendgruppen im Polymeren mittels der Farbverteilungstechnik stützt den für die Übertragungsreaktion der Amine angenommenen Mechanismus.
    Notes: Chain transfer constants of amines have been determined in the polymerization of methyl methacrylate using the mixed-solvent method. The transfer constants are in the order of aniline 〈 methyl aniline 〈 dimethyl aniline. The chain transferring ability of amines has been explained in the light of the polar structure of the transition state. Substitution enhancing electron donating capacity of the amine nitrogen results in higher transferring ability. The decrease in the rate of polymerization due to amines, is in the same order as that of chain transferring capacity and is explained on the basis of hyperconjugation. The estimation of amino end group in the polymer by dye-partition technique supports the mechanism suggested for transfer reaction of amines.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1971.021490119
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  • 12
    Electronic Resource
    Electronic Resource
    Spectroscopic studies on the interaction of Au(III) with nucleosides, nucleotides, and dimethyl phosphate (1977)
    New York : Wiley-Blackwell
    Biopolymers 16 (1977), S. 1863-1878 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of complexes of Au(III) with nucleosides and nucleotides and their methyl derivatives in different stoichiometry have been prepared. Ultraviolet, visible, ir, and nmr studies have been performed to determine the site of binding of these ligands with the metal ion. In (1:4) Au(III): guanosine complex, N7 is the binding site, whereas at 1:1 complex, a bidentate type of chelation through C6O and N7 is observed. C6-NH2 is favored over N1 as coordinating site at all stoichiometry in the adenosine complex. Inosine binds through N1 at r = 1. In cytidine, N1 is the binding site, whereas thymidine reacts only at high pH. In the case of nucleotides a bidentate type of chelation through the phosphate and the ring nitrogen occurs. The phosphate binding ability of Au(III) was further confirmed by studying the interaction of Au(III) with dimethyl phosphate - a conformational analog of the phosphate backbone in DNA chain.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1977.360160904
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  • 13
    Electronic Resource
    Electronic Resource
    Interaction of metal ions with nucleic acids and related compounds. II. Studies on Au(III)-nucleic acid systemPart I of the series appeared in Biopolymers (1973) 12, 1431. This paper is based on the Ph.D. thesis (Indian Institute of Science, 1974) of C.K.S. Pillai. (1978)
    New York : Wiley-Blackwell
    Biopolymers 17 (1978), S. 709-729 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nature of interaction of Au(III) with nucleic acids was studied by using methods such as uv and ir spectrophotometry, viscometry, pH titrations, and melting-temperature measurements. Au(III) is found to interact slowly with nucleic acids over a period of several hours. The uv spectra of native calf-thymus DNA 9pH 5.6 acetate buffer containing (0.01M NaCIO4) showed a shift in λ max to high wavelengths and an increase in optical density at 260 nm. There was a fourfold decrease in viscosity (expressed as ηsp/c). The reaction was faster at pH 4.0 and also with denatured DNA (pH 5.6) and whole yeast RNA (pH 5.6). The order of preference of Au(III) (as deduced from the time of completion of reaction) for the nucleic acids in RNA 〉 denatured DNA 〉 DNA. The reaction was found to be completely reversible with respect KCN. Infrared spectra of DNA-Au(III) complexes showed binding to both the phosphate and bases of DNA. The same conclusions were also arrived at by melting-temperature studies of Au(III)-DNA system. pH titrations showed liberation of two hydroxylions at r = 0.12 [r = moles of HAuCl4 added per mole of DNA-(P)] and one hydrogen ion at r = 0.5. The probable binding sites could be N(1)/N(7) of adenine, N(7) and/or C(6)O of guanine, N(3) of cytosine and N(3) of thymine.DNAs differing in their (G = C)-contents [Clostridium perfingens DNA(G = C, 29%), salmon sperm DNA (G + C, 42%) and Micrococcus lysodeikticus DNA(G + C, 29%), salmon sperm DNA (G = C, 72%)] behaved differently toward Au(III). The hyperchromicity observed for DNAs differing in (G + C)-content and cyanide reversal titrations indicate selectivity toward ( A + T)-rich DNA at lw values of r. Chemical analysis and job's continuous variation studies indicated the existence of possible complexes above and below r = 1. The results indicate that Au(III) ions probably bind to hte phosphate group in the initial stages of the reaction, particularly at low values of r, and participation of the base interaction also increases. Cross-linking of the two strands by Au(III) may take place, but a complete collapse of the doulbe helix is not envisaged. It is probable that tilting of the bases or rotaiton of the bases around the glucosidic bond, resulting in a significant distrotion of the double helix, might take place due to binding of Au(III) to DNA.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1978.360170313
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  • 14
    Electronic Resource
    Electronic Resource
    Binding of gold(III) with DNA (1973)
    New York : Wiley-Blackwell
    Biopolymers 12 (1973), S. 1431-1435 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: No abstract.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1973.360120617
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  • 15
    Electronic Resource
    Electronic Resource
    Morphology of poly(vinylidene fluoride)/poly(methyl acrylate) blends: influence of chain structure (1998)
    Weinheim : Wiley-Blackwell
    Macromolecular Chemistry and Physics 199 (1998), S. 1479-1484 
    Details
    ISSN: 1022-1352
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The morphology of blends of poly(vinylidene fluoride) (PVF2) fractions with poly(methyl acrylate) (PMA), studied by means of polarized light microscopy, exhibits a gradual change in morphology from spherulitic → dendritic → spherulitic both for increasing PMA concentration in the blend and for increasing crystallization temperature. Possible reasons for this change in morphology, viz. the ratio of diffusion constant and growth rate, are discussed. The influence of head to head (H-H) defects of PVF2 on the morphology of the blends is discussed on the basis of the polymer-polymer interaction parameter.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    The influence of chain structure on the equilibrium melting temperature of poly(vinylidene fluoride) (1991)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 29 (1991), S. 1287-1297 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Three poly(vinylidene fluoride) whole polymers were fractionated according to their head-to-head concentrations. Their melting temperatures and fusion properties were studied. Although small but significant differences were found among the fractions obtained from a given parent polymer, a wide range in chain compositions was not obtained. The equilibrium melting temperatures were determined by extrapolating the dependence of the observed melting temperature on the crystallization temperature. A critical analysis is given of this extrapolation method as applied to poly(vinylidene fluoride) and the results are compared with literature reports. The problems involved in explaining the dependence of the equilibrium melting temperatures on the structural irregularities of the chain are given. Possible reasons for the relatively high level of crystallinity that is observed, for what is essentially a copolymer, are also discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1991.090291012
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  • 17
    Electronic Resource
    Electronic Resource
    Biodegradation of gelatin-g-poly(ethyl acrylate) copolymers (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 26 (1981), S. 3633-3641 
    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: Gelatin-g-poly(ethyl acrylate) copolymers were prepared in an aqueous medium, using K2S2O8 initiator. The composition of the graft copolymers was dependent upon temperature and duration of the reaction. The number of grafting sites was small and molecular weight of the grafted poly(ethyl acrylate) branches was high. Three copolymer samples with grafting efficiencies of 33.3%, 61.0%, and 84.0%, were tested for their microbial susceptibility in a synthetic medium employing a mixed inoculum of Bacillus subtilis, Pseudomonas aeruginosa, and Serratia marcescens and the percent weight losses were 12%, 10.1%, and 6.0%, respectively, after 6 weeks of incubation. The extent of degradation seems to decrease with increasing grafting efficiency. There was initial rapid weight loss accompanied by the exponential increase in bacterial population and pH of the culture medium during the first week. The nitrogen analysis also showed the utilization of the polymer. A parallel set of experiments, carried out by employing the samples as the only source of both carbon and nitrogen, showed a marginal but definite increase in the utilization of the polymer.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1981.070261111
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  • 18
    Electronic Resource
    Electronic Resource
    Biodegradation of gelatin graft copolymers. III (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 30 (1985), S. 609-619 
    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: Gelatin-g-poly(methyl acrylate) and gelatin-g-poly(acrylonitrile) copolymers were prepared in an aqueous medium using K2S2O8 initiator. A plausible mechanism has been put forward for the observed grafting behavior of monomers. Gelatin-g-PAN showed a greater resistance to mixed bacterial inolucum compared to gelatin-g-PMA samples. The rate of degradation decreased with the increase in grafting efficiency. A parallel set of experiments carried out by employing the samples as the only source of both carbon and nitrogen showed a marginal but definite increase in the utilization of the polymer. The nitrogen analysis also showed the utilization of the polymer. Scanning electron micographs of the polymer films do show extensive pitting after microbiological testing.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1985.070300213
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  • 19
    Electronic Resource
    Electronic Resource
    Thermogravimetric and mass-spectrometric study of the thermal decomposition of PBCT resins (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 1797-1808 
    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 decomposition of three commercial samples of carboxy-terminated polybutadiene (PBCT) resins was studied by thermogravimetric analysis (TGA) at heating rates varying from 2° to 100°C/min. Kinetic parameters of the decomposition process at different heating rates were evaluated by means of the Fuoss method.1 The decomposition process and the activation energy values are found to be dependent on heating rate. Mass-spectrometric analysis of the decomposition products shows that the pyrolysis products of PBCT resins are mainly low molecular weight hydrocarbons: ethylene, acetylene, butadiene, propadiene, vinylcyclohexene, etc. The rates of evolution of these hydrocarbon products vary with the carboxy content of the PBCT resin. Based on this, a carbonium ion mechanism has been suggested for the thermal decomposition. The data generated from this work are of importance for a consideration of the mechanism of combustion of composite solid propellants based on PBCT binders.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240803
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  • 20
    Electronic Resource
    Electronic Resource
    Biodegradation of gelating-g-poly(ethyl acrylate) copolymers. II (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 3075-3085 
    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: Gelatin-g-poly(ethyl acrylate) copolymers were prepared in an aqueous medium using K2S2O8 initiator. Three copolymer samples with grafting efficiencies of 33.3%, 61.0%, and 84.0% were tested for their microbial susceptibility in a synthetic medium with pure cultures of Pseudomonas aeruginosa, Bacillus subtilis, and Serratia marcescens. The percent weight losses were recorded over 6 weeks of incubation period in nitrogen-free and nitrogen-rich media. The relationship between [log (rate)] during the first week of the test period and the composition of grafted samples showed a linear behavior. Pure cultures were more effective than the mixed inoculum, although there was no essential difference in the agressivity of different bacterial stains. Growth-time curves and pH measurement also complement these observations.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070291012
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