A comparative dielectric spectroscopy investigation of beta-cyclodextrin polymer and carboxymethyl beta-cyclodextrin polymer cross-linked by epichlorohydrin
| Autor: | John C. Papaioannou, Chaido Stefania Karagianni, Panagoula K. Papaioannou |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Arrhenius equation
chemistry.chemical_classification Range (particle radiation) 010405 organic chemistry Hydrogen bond Organic Chemistry Polymer Dielectric 010402 general chemistry 01 natural sciences 0104 chemical sciences Analytical Chemistry Dielectric spectroscopy Inorganic Chemistry symbols.namesake chemistry.chemical_compound chemistry symbols Physical chemistry Epichlorohydrin Beta (velocity) Spectroscopy |
| Zdroj: | Journal of Molecular Structure. 1182:230-240 |
| ISSN: | 0022-2860 |
| DOI: | 10.1016/j.molstruc.2019.01.044 |
| Popis: | The β-cyclodextrin polymer (β-CDP) and the carboxymethyl-β-cyclodextrin polymer (CM-β-CDP) cross-linked by epichlorohydrin were investigated by dielectric spectroscopy over the frequency range 0.1–100 kHz in the temperature ranges 132.6–464.8 K and 132.9–500.9 K, respectively. The β-CDP reveals a reversible order-disorder transformation of some normal hydrogen bonds to flip-flop type at Ttrans = 220.1 K, whereas the CM-β-CDP doesn't show any transformation of hydrogen bonds. The ac-conductivity plot of β-CDP (lnσ vs 1/T) shows a linear part obeying the Arrhenius equation in the range 289.8–268.8 K with Eα = 0.71 eV during cooling and 0.77 eV during heating. A deformed bell-shaped curve with maximum values at Ttrans = 222.7 K during cooling and 223.8 K during heating in the range 132.6–268.8 K, is due to the hydrogen-bonded transformation. At 328.9 |
| Databáze: | OpenAIRE |
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