Li. Palade et al., A MODIFIED FRACTIONAL MODEL TO DESCRIBE THE ENTIRE VISCOELASTIC BEHAVIOR OF POLYBUTADIENES FROM FLOW TO GLASSY REGIME, Rheologica Acta, 35(3), 1996, pp. 265-273
The dynamic mechanical behavior of a series of monodisperse polybutadi
enes has been investigated from the flow regime to the glassy state. A
ssuming a linear superposition of the entanglement and glass behavior
a mathematical model of the spectrum of relaxation times is developed.
It consists in a selfsimilar spectra for the entanglement contributio
n and a Fractional Maxwell Fluid (FMF) for the glassy contribution. Th
e model closely represents the master curves of dynamic moduli over 15
logarithmic decades of frequency with three parameters for the flow r
egime (G(N)(o), eta(o) and a cut-off parameter lambda(max)) and four p
arameters for the FMF. It is shown that one of the parameter of the FM
F is similar to the power-law exponent of a self-similar spectra previ
ously proposed in the literature to model the transition to glass.