SbstractThe rheological properties of acrylic paints and polyaniline (PAni) blends, with different contents of PAni doped by dodecyl benzene sulphonic acid (DBSA) and, dispersed by mechanical stirrer and ultrasonic, were investigated by controlled shear rate testing ramps. The results showed that the commercial acrylic paint had tended to deliver the required stability on the blends, in order to avoid sedimentation process. All samples exhibited non-Newtonian flow behavior (shear thinning), increasing PAni content the flow behavior index (n) decreased (0.41 to 0.11) and power law model were used to fitted the experimental curves. The results showed that the addition of PAni-DBSA affects the viscoelastic behavior of the mixtures due to the interactions between the components in the mixture. The best properties were obtained for samples 90/10 wt % dispersed by ultrasonic, indicating the feasibility of the usage as a conducting paint.

Using controlled shear-rate testing ramps, this study investigates the rheological properties of carboxymethycellulose (CMC)/starch blends, with and without zinc oxide (ZnO). Viscosity decreased as the amount of starch increased and after adding 1% ZnO. The creep and recovery tests indicated that, with increasing starch content, there was a decrease in elasticity and the viscosity zero shear rate. The results also showed, in the temperature range between 25 and 70 8C, an inversion occurred in the elastic and viscous moduli behavior, obeying the Arrhenius equation. The addition of ZnO affects the viscoelastic behavior and the morphology of the blends. The best survival results were obtained for samples 50/50 and 60/40 wt% (CMC/starch).

The rheological behavior of the carboxymethylcellulose (CMC) / starch blends with and without zinc oxide (ZnO) have been investigated by controlled shear rate testing ramps. All blends showed high shear thinning flow behavior, (n=0,10 - 0,32) without ZnO and (n=0,10-0,29) with ZnO. The consistency index (K) and apparent viscosity (ηa,100 ) decreased with increasing amount of starch and with the addition of 1% wt ZnO. The results also showed that occurs an inversion in the elastic and viscous modulii behavior between 25 and 700C, obeying the Arrhenius equation. The study of activation energy showed that ZnO acts in the CMC phase, increase of viscosity of mixtures. The creep and recovery test indicated a decrease in the viscosity zero shear rate, indicating an increase of viscous character.  The phase angle results also confirm an increase of viscosity with addition of ZnO.