We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Proton mobility and copper coordination in polysaccharide- and gelatin-based bioblends and polyblends.
- Authors
Mattos, R.; Tambelli, C.; Raphael, E.; Silva, I.; Magon, C.; Donoso, J.; Pawlicka, A.
- Abstract
Polysaccharide- and gelatin-based bioblends and polyblends were synthesized and characterized by complex impedance spectroscopy, proton nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). Higher ionic conductivities of 7.9 × 10 S/cm at room temperature and 2.5 × 10 S/cm at 80 °C were obtained for the agar-chitosan polyblends. For all samples, the activation energies, calculated from the Arrhenius plot of ionic conductivity and from the onset of NMR line narrowing, are in the range 0.30-0.86 and 0.38-0.57 eV, respectively. The glass transition temperatures ( T) varied from 200 to 215 K, depending on the sample composition. The temperature dependence of the H spin-lattice relaxation revealed two distinct proton dynamics. The EPR spectra are characteristic of Cu ions in tetragonally distorted octahedral sites. Quantitative analysis of the EPR spin Hamiltonian g and A parameters revealed copper ions complexed by nitrogens and oxygens in the samples containing chitosan or gelatin and only by oxygens in agar-based ones. The in-plane π bonding is less covalent for the gelatin and chitosan blends. Results suggest that natural bioblends and polyblends are interesting systems to be used in materials science engineering.
- Subjects
PROTONS; COPPER; POLYSACCHARIDES; GELATIN; IONIC conductivity
- Publication
Cellulose, 2014, Vol 21, Issue 4, p2247
- ISSN
0969-0239
- Publication type
Article
- DOI
10.1007/s10570-014-0262-y