Proton mobility and copper coordination in polysaccharideand gelatin-based bioblends and polyblends

Autor(es)

Mattos, R. I. ^{[1, 2]} ; Tambelli, C. E. ^[1] ; Raphael, E. ^{[2, 3]} ; Silva, I. D. A. ^[4] ; Magon, C. J. ^[4] ; Donoso, J. P. ^[4] ; Pawlicka, A. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, FZEA, BR-13635900 Pirassununga, SP - Brazil

^[2] Univ Sao Paulo, IQSC, BR-13566590 Sao Carlos, SP - Brazil

^[3] Univ Fed Sao Joao Del Rei, DCNAT, BR-36301160 Sao Joao Del Rei, MG - Brazil

^[4] Univ Sao Paulo, IFSC, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Cellulose; v. 21, n. 4, p. 2247-2259, AUG 2014.
• Citações Web of Science: 2

Resumo

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 x 10 (-5) S/ cm at room temperature and 2.5 x 10 (-3) S/ cm at 80 degrees C were obtained for the agarchitosan 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 (Tg NMR) varied from 200 to 215 K, depending on the sample composition. The temperature dependence of the 1 H spin-lattice relaxation revealed two distinct proton dynamics. The EPR spectra are characteristic of Cu 2 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 p 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. (AU)

• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs