Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
AN EXPERIMENTAL INVESTIGATION OF THE TEMPERATURE INFLUENCE ON THE VISCOUS MODULUS AND GELATION TRANSITION OF A POLYMERIC SOLUTION.
Submission Author:
Igor Dal Osto Pereira , DF
Co-Authors:
Francisco Ricardo Cunha, Igor Dal Osto Pereira
Presenter: Igor Dal Osto Pereira
doi://10.26678/ABCM.COBEM2017.COB17-1899
Abstract
The viscoelastic modulus and the gelation transition of an aqueous polymer suspenion (Polaxamer 407) is investigates experimentally. The dependence of the viscometric modulus on time, shear rate, temperature, macromolecule volume fraction and additive concentration is examined. The experimental investigations are carried out with eight sample of Polaxamer. Four of these sample are tested with the aqueous polymeric suspension in the absence of additives for different macromolecule volume fraction. The other four samples are produced form the first one by adding Clobetazol and a surfactant called Sodium Dodecyl Sulphate (SDS). All samples are sheared in a high performance rheometer of parallel disk with an automatic control of gap. The first tests are carried out under condition of steady shear over five experimental realizations. We obtain results of the Polaxamer viscosity as a function of time and we also investigate the shear rate dependence viscosity of the polymer solution for two different temperatures, 6 °C and 36 °C. While a shear thinning behavior of the polaxamer is verified for the temperature of 36 °C, a non shear rate dependence viscosity is observed at 6 °C for all samples. The second tests deals with non-isothermal experimental trials under a regime of small amplitude oscillatory shear, in a temperature range from 3.5 to 50 °C. The viscoelastic modules of storage and loss of energy are determined as a function of the temperature. In addition, the gelation transition of the polymer solution is characterized as a sudden change in the viscoelastic modulus. We show a plot of the gelation temperature as a function of the polymer volume fractions. This interesting finding is directly associated with microstructure induced transition as the temperature increases. We also present a typical result for the shear elastic modulus of the polymer as a function of the polymer volume fraction for 6 °C. This show that the micelles like chain formation at a given temperature leads to a solid characteristic of the polymer that can be interpreted as a yields stress.
Keywords
Rheometry, complex fluid, gelation, polymer suspension, thermosentivity, yield stress.
