ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 47 (1996), S. 357-360 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Enzymatic ring-opening polymerization of a 16-membered lactone, 15-pentadecanolide (PDL), has been carried out in bulk using various lipases of different origin as catalyst. The polymerization with Pseudomonas fluorescens lipase (lipase PF) catalyst afforded the corresponding polyester in high yields. The rate of the polymerization catalyzed by lipase PF at a temperature lower than 45°C was very small, whereas the polymerization at higher polymerization temperature (≥60°C) proceeded much faster. Lipase derived from Pseudomonas cepacia was also active for the polymerization of PDL. The polymerization catalyzed by Candida cylindracea lipase at high temperature (75°C) afforded the polymer with molecular weight up to 2.0 x 104. The polymerization behavior of PDL through lipase catalysis has been compared with that of ε-caprolactone (ε-CL). PDL showed an enzymatically higher polymerizability than ε-CL, despite the smaller ring-strain of PDL, which is due to the stronger recognition of PDL by lipase. Enzymatic copolymerization of PDL with other lactones using lipase PF catalyst produced copolymers with molecular weight of several thousands. From 13C NMR analysis, the diad sequence distributions were determined.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 50 (1993), S. 2217-2222 
    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: Composite films composed of poly(diisopropyl fumarate-co-styrene) (PFS) and nematictype liquid crystal (E8) (40/60 by weight) were prepared by solvent casting in chloroform at room temperature. Scanning electron microscopy measurement showed that a liquid crystal phase is continuously embedded in a spongy-like PFS martrix. Optical responses of the composite films under the conditions of an externally imposed ac electric field (60-240 Vp-p, 10-1000 Hz), temperature (290-355 K), and a film thickness (8-16 μm), were determined using an He-Ne laser (wavelength 632.8 nm). The results obtained indicated that, under the conditions imposed, the output can be continuously controlled, and the response time is only of several milliseconds or less. In addition, the response to temperature sweep, heating and cooling, was reversible with only a delay, and it was interpreted in terms of the rigidity and thermal stability of the matrix polymer. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...