Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 1985-1989  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Structural features of poly(alkylene ether carbonate) diol oligomers by capillary gas chromatography (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 183-200 
    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 series of poly(ethylene ether carbonate) diol oligomers were synthesized from ethylene carbonate (EC) using various catalysts and low EC:initiator molar ratios. The structures of these oligomers have been studied by alkaline degradation to the poly(ethylene glycol)s, which make up their backbone, followed by capillary gas chromatographic (CGC) analysis. Comparisons of CGC traces before and after hydrolysis indicate which volatile components contain carbonate moieties. Some poly(ethylene glycol)s were not chemically bound into the polymer backbone and were analyzed directly by CGC. Based on the combination of analytical techniques developed in this study, it is possible for the first time to establish the approximate composition of a given poly(ethylene ether carbonate) diol. A typical composition made using a sodium stannate trihydrate catalyst consists of (1) an oligomeric portion which is a copolymer of carbon dioxide and poly(ethylene glycol)s and (2) a monomeric portion which consists mostly of diethylene glycol with lesser quantities of monoethylene glycol, triethylene glycol, 1,4-dioxane and unreacted ethylene carbonate.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370114
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Structural features of poly(alkylene ether carbonate) diols and intermediates formed during their preparation (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 37 (1989), S. 1491-1511 
    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: Capillary vapor-phase chromatography and carbon-13 nuclear magnetic resonance (NMR) have been used to elucidate the structure of poly(ethylene ether carbonate) diols and certain intermediates produced by the oligomerization of ethylene carbonate (EC) using monoethylene glycol (MEG) or diethylene glycol (DEG) as initiator and catalyzed by sodium stannate trihydrate. These diols are alternating copolymers of carbon dioxide and DEG which also contain smaller amounts of higher glycols as determined by comparing their 13C NMR spectra to the spectra of model compounds. Diethylene glycol is an important reaction intermediate and is present in steady-state concentrations. Although both 2-hydroxyethyl carbonate and 2-hydroxyethyl ether end groups are present at an intermediate stage in the reaction, only 2-hydroxyethyl ether end groups are present at high EC conversion. Molecular weight builds as a smooth function of conversion and time.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070370605
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Molecular weight advancement of poly(ethylene ether carbonate) polyols (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 38 (1989), S. 463-476 
    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: Poly(ethylene ether carbonate) polyols have been prepared from ethylene carbonate and monoethylene glycol (MEG) or diethylene glycol (DEG) using sodium stannate trihydrate as catalyst. When these polyols (catalyst removed) are heated to elevated temperatures (〈 180°C) at reduced Pressures, volatile impurities are removed, as distillate, molecular weight builds in a controllable manner. This is thought to be a transesterification process in which —OC(O)CH2CH2OCH2CH2OH end groups on one molecule react with carbonate moieties on a second molecule with loss of DEG. These advanced polyols form rapidly with high CO2 retention and relatively low polydispersity. This process has been characterized by size exclusion chromatography, quantitative capillary gas chromatography of the distillates, 13C-NMR of the products, and alkaline hydrolysis of the products followed by quantification of the resultant glycols. The advanced polyols are largely alternating copolymers of DEG and CO2. They are valuable polyols for polyurethane fabrication.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1989.070380306
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...