Influence of the binder composition on the water debinding properties of a PVB-PEG-alumina feedstock for the fused deposition of ceramic process

The study investigates the influence of several binder compositions on the solvent debinding characteristics of highly filled thermoplastic alumina feedstocks at different temperatures. All feedstocks contain the same powder volume fraction but vary in the repartition of the binder components: polyvinyl butyral (PVB), polyethylene glycol (PEG), and a plasticizer (3G8). The weight loss, debinding speed, volumetric changes, and the microstructure were analyzed. The water temperature was set to room temperature –RT– (23°C) and 40°C. SEM micrographs were taken on as-processed and solvent-debinded samples fractured after dipping in liquid nitrogen. Water debinding of the compositions with high proportions of low molecular weight components PEG and 3G8 helps to reduce the remaining polymer amount and to achieve an open porosity, which should ease the following thermal debinding.