Sago starch as binder and pore-forming agent for the fabrication of porcelain foam

The aim of this study is to verify the potential of sago starch (Metroxylon sagu) as a binder and pore-forming agent for the fabrication of porcelain foam. The porcelain foam was fabricated via the polymeric foam replication technique. Initially, the porcelain raw material was mixed in water with several binders (respectively) to form a slurry. Replication starts by fully submerging a compressed sponge in the slurry. Excess slurry was then removed by hand squeezed and pressed between two parallel plates. Subsequently, the impregnated sponge was sintered at 500 °C and up to 1250 °C for 2 h for sponge and binder removal and porcelain to mature, respectively. The results from this work showed that sago starch slurry produced porcelain with density, total porosity and compressive strength of 0.37–0.51 g cm−3, 79–81%, and 0.33–0.93 MPa, respectively. The increased of porosity and compressive strength are perhaps due to the addition of sago starch which changed the rheological property of the slurry from Newtonian to pseudoplastic behavior. This results in higher value of viscosity, consequently allowing the construction of smoother and uniform cell skeleton although with existence of micro-pores on the structure, which contributed to higher compressive strength. The results from this study showed that sago starch has huge potential as a binder and a pore-forming agent, whilst providing a simpler and cheaper route for the fabrication of cellular ceramics.