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  • 1
    Electronic Resource
    Electronic Resource
    A viscosity-molecular weight relationship for polydimethylsiloxanes (1961)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 5 (1961), S. 153-156 
    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 relationship of intrinsic viscosity [η] to the weight-average molecular weight M̄w of polydimethylsiloxane in toluene at 25°C. has been determined. The modified Staudinger equation, [η] = KM̄wa, with K = 2.43 × 10-5 and a = 0.84, describes the relationship for the above polymers in the range of weight-average molecular weight from 18,900 to 124,500 (as determined by light-scattering measurements). These constants differ from the values reported by Barry, where K = 2 × 10-4 and a = 0.66 were obtained. The difference is attributed to the fact that Barry dealt with number-average rather than weight-average molecular weight.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1961.070051404
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  • 2
    Electronic Resource
    Electronic Resource
    High-temperature reactions of hydroxyl and carboxyl PET chain end groups in the presence of aromatic phosphite (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 1281-1296 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: When melt-extruded in the presence of triphenylphosphite (TPP), the molecular weight of polyesters such as poly(ethylene terephthalate) (PET) increases with time. Analysis of the PET chain end groups and model studies of high-temperature reactions indicate that, most likely, the process leading to chain extension of PET in the presence of TPP takes place in two steps. In the first step, TPP rapidly reacts with the hydroxyl end groups by displacing one phenoxy group from the TPP. In the second step, a slow reaction takes place between the alkyldiphenyl phosphite and carboxylic chain end groups, forming an ester bond between the carboxyl and alkyl groups, and producing diphenylphosphite (DPP) as a reaction by-product. The DPP tautomerizes to its pentacovalently bonded stabler form of diphenylphosphate, the form in which the DPP was usually detected in our analyses. The ester formation results in the extension of the PET chains. Model studies are presented which support the proposed mechanism.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080240614
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  • 3
    Electronic Resource
    Electronic Resource
    Proton magnetic resonance study of sorption of water and alcohols by wool (1964)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 2 (1964), S. 3191-3196 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Measurements have been made of the proton magnetic resonance spectra of water, methanol, and ethanol sorbed by wool. The line widths of the spectra are related to the freedom of movement (mobility) of the sorbate molecules within the protein structure. At any particular value of molar sorption it is found that the mobilities of water, methanol, and ethanol are approximately equal, but the increase in volume of the wool increases in this series in the approximate ratio of 1 : 2 : 3. Thus, when a comparison is made of the mobility of the three sorbates at equal values of the volume swelling it is found that the order of mobility is water 〉 methanol 〉 ethanol.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1964.100020718
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  • 4
    Electronic Resource
    Electronic Resource
    Structural investigation of polyacrolein by fractional dehydrationPresented in part at the 148th Meeting of the American Chemical Society, Chicago, September 1964. (1965)
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 3471-3484 
    Details
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The utilization of a specially developed technique for the low temperature pyrolysis of polyacrolein, and the accurate measurement of the waterr eleased thereby from the polymer have demonstrated the presence of well-defined inflection points in the curve of water evolution versus dehydration (pyrolysis) temperature. These are postulated to indicate the presence of water in polyacrolein from a number of different sources, e.g., structural, hydrogen-bonded, and free. A correlation of the measured water evolution between inflection point temperatures with the concurrently developing free carbonyl groups, measured by an infrared technique, has provided information on the type and proportion of various structural subunits in the polyacrolein molecule. This information has been used to construct a partial structural formula for the particular polyacrolein sample under examination. As a practical outgrowth of this work, the concept of the activation of polyacrolein by dehydration at elevated temperatures has proved useful in facilitating reaction of the polymer with a number of carbonyl reagents such as sodium bisulfite, SO2, etc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1965.100031011
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