Tape casting aqueous alumina suspensions containing a latex binder

摘要

The tape casting of ceramic membrane substrates of ∼1 mm thickness has been studied using two grades of ammonium polymethylacrylate (PMA) as a dispersing agent, dibutylphthalate as a plasticizer and polyvinylacetate (PVAc) latex as a binder. The colloidal stability of the alumina particles in the precursor slip was characterized using zeta potential measurements and the rheological behaviour of the slips. After tape casting, the density, strength and flexibility of the green tapes were studied in terms of changes in the plasticizer concentration and pH of the slip. The results indicated that alumina particles could be stabilized at pH 6–10 at a PMA15 concentration of 10 mg g−1. The slips prepared with the polyelectroyte also displayed a strong shear thinning effect, which is important for tape casting. With the proper addition of plasticizer and adjustment of pH, it was found that a PVAc latex-based system can yield green alumina tapes with high green strength and flexibility.