Rheometry of Complex Fluids with Time-Temperature Dependent Rheology

The paper is dedicated to the rheometry and time-temperature rheology of complex fluids in simple and oscillatory shear flows. The main aim of the study is to establish a general framework for modeling the material functions, which characterize the internal structure evolution of viscoelastic fluids. The proposed constitutive relation is similar to the analogic 3-contants Jeffreys model, or the differential Oldroyd models, but with viscosity and time coefficients dependent on a structural variable. The samples used in experiments are polymers (solution and melts) and lubricants (oil and grease), fluids with internal network structure evolving as function of the test temperature and/or experimental time. The results of the study are directly related to the macroscopic modeling of the gelation mechanism and have potential applications in the modeling of the curing processes.