Rheological and chemical analysis of reverse gelation in a covalently crosslinked Diels-Alder polymer network
A network polymer, incorporating dynamic and reversible crosslinks, was synthesized using the Diels-Alder reaction. Fourier transform infrared (FTIR) spectroscopy was used to characterize the reaction rate and thermodynamic equilibrium over a broad temperature range. Equilibrium conversion of the fu...
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| Published in | Macromolecules Vol. 41; no. 23; pp. 9112 - 9117 |
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| Main Authors | , , , , |
| Format | Journal Article |
| Language | English |
| Published |
United States
09.12.2008
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| Online Access | Get full text |
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| Summary: | A network polymer, incorporating dynamic and reversible crosslinks, was synthesized using the Diels-Alder reaction. Fourier transform infrared (FTIR) spectroscopy was used to characterize the reaction rate and thermodynamic equilibrium over a broad temperature range. Equilibrium conversion of the furan and maleimide varied from 74% at 85°C to 24% at 155°C, demonstrating significant depolymerization via the retro-Diels-Alder reaction. The gel point temperature, as determined by rheometry using the Winter-Chambon criterion, was 92°C, corresponding to a gel-point conversion of 71%, consistent with the Flory-Stockmayer equation. The scaling exponents for the complex moduli, viscosity, and plateau modulus, in the vicinity of the gel-point, were determined and compared with experimental and theoretical literature values. Further, the material exhibited a low frequency relaxation owing to dynamic rearrangement of crosslinks by the Diels-Alder and retro-Diels-Alder reactions. |
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| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Current address: Center for Bioengineering, Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309-0427, USA. |
| ISSN: | 0024-9297 |
| DOI: | 10.1021/ma801863d |