Dynamic rheological measurements of aqueous polyester dispersion in batch reactor and twin screw extruder

This paper reports on inline measurement techniques for the rheological behavior of aqueous polyester dispersion in batch reactor and twin screw extruder (TSE). Since the preparation of latex without hazardous solvent is a relatively new technique, very little has been reported to understand the kinetic aspects of the process for both batch reactor and TSE. A sudden viscosity drop is observed in a batch reactor whereas the viscosity tends to oscillate in TSE during the addition of water when surface tension is low enough. The viscosity changes during the addition of water are thought to be related to the morphological changes during the process since surfactant must be present else no change occurs. In this paper, different surfactant and NaOH concentrations have been studied for their influence on the viscosity so that emulsification may become a predictable process in a TSE.