Correlating the rheology of PVC-based pastes with particle characteristics

This work deals with the rheological characterization of P VC plastisols. Plastisols are suspensions of fine particles in a plasticizer and have a wide commercial application. Rheological behavior is a fundamental control parameter for the final application stage of those pastes that normally undergo an aging process. This work seeks to understand the interaction mechanisms (particle/particle and particle/fluid) that condition the system rheology. It was possible to confirm that paste rheology is controlled by the particle characteristics, including the strength of the polymer aggregates. Moreover, as aging progressed, the rheological behavior changed, followed by changes in the particles' structures. This is particularly important when the plastisol is used to coat a substrate, since the spreading stage is strongly affected by paste rheology. Herein, the laser diffraction spectroscopy (LDS) technique was adjusted to analyze the particles in the concentrated emulsion, avoiding structure damage through an adequate dilution with an organic solvent.