Study of dielectric relaxations in cellulose by combined DDS and TSC

Golnaz Jafarpour (1) , Eric Dantras (1) , Alain-Michel Boudet (2) , Colette Lacabanne (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
2 SCSV - Surfaces Cellulaires et Signalisation chez les Végétaux

In this work, thermally stimulated currents (TSC) analyses combined with dynamic dielectric spectroscopy (DDS) have been applied to the investigation of molecular mobility of cellulose. The correlation between results obtained by both methods allows us to attribute the low temperature DDS relaxation mode to the c-mode resolved in TSC. The values of its activation parameters point out that the chain mobility remains localized. At high temperature, the various dielectric relaxation phenomena are separated by applying a recent analytical protocol. The comparison between the activation enthalpy values obtained by DDS and TSC leads to the assignment of the socalled a-mode to cooperative movements of polymeric sequences. The Arrhenius behavior of a-relaxation time is explained using the strong/fragile pattern. The influence of water content on secondary and primary relaxation modes was examined as well.

Mots clés: Biopolymers; Dielectric properties; relaxation; electric modulus; Thermally stimulated and depolarization current

Domaines: Matériaux

Golnaz Jafarpour, Eric Dantras, Alain-Michel Boudet, Colette Lacabanne. Study of dielectric relaxations in cellulose by combined DDS and TSC. Journal of Non-Crystalline Solids, 2007, vol. 353, pp. 4108-4115. ⟨10.1016/j.jnoncrysol.2007.06.026⟩. ⟨hal-00808417⟩