N. Elkissi et al., SHEAR RHEOMETRY OF POLYDIMETHYLSILOXANES - MASTER CURVES AND TESTING OF GLEISSLE AND YAMAMOTO RELATIONS, Rheologica Acta, 32(3), 1993, pp. 293-310
This study concerns the shear rheometry of a series of nine silicone f
luids, all linear or branched polydimethylsiloxanes (PDMS), with varyi
ng mass distributions. The use of a rotative rheometer enabled charact
erization of these products in a dynamic regime for about five decades
of pulsation omega. In addition, because of the use of rotative rheom
eters together with a capillary rheometer with controlled piston speed
, the behavior of these products could be determined for about six ord
ers of magnitude of shear rate lambda, notably for the permanent regim
e viscosity coefficient eta. On the other hand, to obtain the variatio
ns of the first normal stress difference coefficient psi1, over a sign
ificant range of shear rate gamma, it was necessary to complete the ex
perimental measurements by using empirical relations. Particularly, af
ter having defined the application conditions, the Gleissle and Yamamo
to relations were tested for these products. Finally, all the results
obtained in dynamic and in transitory regimes by using the rheometers
and empirical relations mentioned above were combined in dimensionless
form. Indeed, the existence of master curves for the linear and branc
hed PDMS was demonstrated. Our study therefore enables the validity of
the master curve method, initially established for a series of linear
monodisperse polystyrenes, to be extended to the case of a family of
linear or branched PDMS of wide mass distribution.