Rheological behavior of cellulose/monohydrate of N-methylmorpholine N-oxide solutions. Part 2. Glass transition domain

Dynamic mechanical experiments performed with original conditions allowed t he analysis of a solution containing 15% cellulose dissolved in a monohydra te of N-methylmorpholine N-oxide (NMMO) in the amorphous state. The glass t ransition zone is studied by dynamic tensile experiments, while dynamic tor sion technique is used to determine the viscoelastic behavior in the glassy state. A master curve of the storage and loss modulus versus frequency can be deduced from the isochronal curves measured by both techniques. This wo rk allows one to complete the corresponding master curve obtained for the ' liquid' state and presented in a previous work [Rheol. Acta 1998;37: 107]. The measurements below the glass transition temperature exhibit two seconda ry relaxations. A modeling of the overall viscoelastic behavior, using the Nowick and Berry approach and the quasi-point defect theory, is proposed. P hysical parameters deduced from this modeling are then discussed. (C) 2001 Published by Elsevier Science Ltd.