Dielectric and dynamic mechanical relaxation studies on poly(aryl ether ketone)s
| Autor: | James N. Hay, Andy A Goodwin |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Arrhenius equation
chemistry.chemical_classification Materials science Polymers and Plastics Thermodynamics Activation energy Polymer Dielectric Dynamic mechanical analysis Condensed Matter Physics Amorphous solid symbols.namesake chemistry Polymer chemistry Materials Chemistry symbols Relaxation (physics) Physical and Theoretical Chemistry Glass transition |
| Zdroj: | Journal of Polymer Science Part B: Polymer Physics. 36:851-859 |
| ISSN: | 1099-0488 0887-6266 |
| DOI: | 10.1002/(sici)1099-0488(19980415)36:5<851::aid-polb12>3.0.co;2-8 |
| Popis: | The relaxation behavior of four amorphous poly(aryl ether ketone)s was investigated using dielectric relaxation spectroscopy and dynamic mechanical analysis. The temperature dependence of the relaxation times of the glass transition process and the cooperative nature of this process were unaffected by changes in polymer structure. The temperature location of the loss peaks for all polymers progressed smoothly between the low frequency of the mechanical measurements and the higher frequencies of the dielectric probe. Differences were observed in mechanical activation energy and dielectric relaxation strength for one polymer which contained a significant concentration of meta linkages, compared with the para-linked polymers, while relaxation broadness was generally greater in the dynamic mechanical mode. Changes in chemical structure had little effect on the shape, intensity, and location of the β-relaxation peak, the main observation being that the Arrhenius activation energy measured by dynamic mechanical analysis was significantly higher than that calculated from the dielectric data. The dielectric β-relaxation was sensitive to absorbed moisture. |
| Databáze: | OpenAIRE |
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