PEO/fatty acid blends for thermal energy storage materials. Structural/morphological features and hydrogen interactions
| Autor: | Krzysztof Pielichowski, D. Biniaś, Jacek Jenczyk, Kinga Pielichowska, Janusz Lekki, S. Głowinkowski |
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| Rok vydání: | 2008 |
| Předmět: |
Materials science
Polymers and Plastics Ethylene oxide Hydrogen bond Crystallization of polymers Organic Chemistry technology industry and agriculture General Physics and Astronomy macromolecular substances Lauric acid law.invention chemistry.chemical_compound Crystallinity chemistry Chemical engineering law Polymer chemistry Saturated fatty acid Materials Chemistry Stearic acid Crystallization |
| Zdroj: | European Polymer Journal. 44:3344-3360 |
| ISSN: | 0014-3057 |
| DOI: | 10.1016/j.eurpolymj.2008.07.047 |
| Popis: | Application of poly(ethylene oxide)-based materials as efficient thermal energy storage systems requires understanding of structural and morphological issues that govern the thermal transitions of the blends. Poly(ethylene oxide)/lauric acid and poly(ethylene oxide)/stearic acid blends show high values of heat of melting and heat of crystallisation which exceed theoretically determined values – it is a synergistic effect that is advantageous in terms of energy storage. The PEO blends were investigated by PLM, SEM, AFM, WAXD, SAXS and 1H NMR techniques – PLM, SEM and AFM allows to observe regions, in which parallelly-packed crystals of fatty acid are present. WAXD results of PEO/fatty acid blends confirmed hindered crystallization of PEO in PEO/fatty acid blends and, finally, lower degree of polymer crystallinity. The NMR study shows that mixing of PEO and lauric acid results in an increase of PEO amorphous phase content in blends as compared to the pure PEO. From FTIR spectra, taken during melting and crystallization, it can be seen that for both investigated blends in the solid state there is only one maximum of band from ν(C O) (in position indicating that C O groups are engaged in formation of hydrogen bonds), while in the liquid state there are two maxima – position of the first maximum is characteristic for ν(C O) vibrations of C O groups that do not participate in formation of hydrogen bond, whereas position of the second maximum in the liquid state proves the presence of C O groups involved in formation of hydrogen bonds. Solid state NMR analysis reveals no esterification reactions between PEO and fatty acid. |
| Databáze: | OpenAIRE |
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