Molecular α-relaxation process of exopolysaccharides extracted from Nostoc commune cyanobacteria
| العنوان: | Molecular α-relaxation process of exopolysaccharides extracted from Nostoc commune cyanobacteria |
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| المؤلفون: | Fernando G. Torres, Omar P. Troncoso, Daniel López, Karen N. Gonzales |
| المساهمون: | Pontificia Universidad Católica del Perú |
| المصدر: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| بيانات النشر: | Elsevier BV, 2020. |
| سنة النشر: | 2020 |
| مصطلحات موضوعية: | Cyanobacteria, Dopin, 02 engineering and technology, Chemical Fractionation, BDS, Biochemistry, Chloride, 03 medical and health sciences, chemistry.chemical_compound, Exopolysaccharide, Structural Biology, medicine, Molecular Biology, 030304 developmental biology, chemistry.chemical_classification, Nostoc commune, 0303 health sciences, biology, Spectrum Analysis, Monosaccharides, Polysaccharides, Bacterial, Doping, Temperature, General Medicine, Polymer, 021001 nanoscience & nanotechnology, biology.organism_classification, Ammonium iodide, chemistry, Chemical engineering, α-Relaxation, Relaxation (physics), Carboxymethylation, 0210 nano-technology, Glass transition, medicine.drug |
| الوصف: | Broadband dielectric spectroscopy was used to investigate the molecular α-relaxation of the exopolysaccharides (EPS) extracted from Nostoc commune cyanobacteria. The EPS were modified in different ways. EPS were carboxymethylated to obtain carboxymethyl-exopolysaccharides (CEPS). EPS and CEPS were doped with ammonium iodide and 1-butyl-3-methylimidazolium chloride. An α relaxation process was observed for all specimens. The temperature dependence of the relaxation times for pure and doped, EPS and CEPS polymers exhibited non-Arrhenius behavior. This relaxation process was associated with the glass transition of the complex heteropolysaccharides produced by the cyanobacteria. The molecular mobility at the glass transition, T, was affected by both the carboxymethylation treatment and the doping. The fragility index also decreased for the doped specimens, which may be attributed to an increase in the mobility of the polymer chains due to the plasticizing effect of the doping agents. The authorswould like to thank Prof. Carlos A. Stortz andDr.Diego A. Navarro for the monosaccharide compositions analysis of EPS. S. Rodriguez is greatly acknowledged for experimental assistance with the DSC tests. The authors acknowledge financial support received from the Vice-rectorate of Research of the Pontificia Universidad Católica del Perú (VRI-PUCP-695). |
| تدمد: | 0141-8130 |
| DOI: | 10.1016/j.ijbiomac.2020.07.268 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0e5ce6c1d6a3bdd61cffdaae90363bd5 https://doi.org/10.1016/j.ijbiomac.2020.07.268 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....0e5ce6c1d6a3bdd61cffdaae90363bd5 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 01418130 |
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| DOI: | 10.1016/j.ijbiomac.2020.07.268 |