Publication: Effect of polyvinyl alcohol (PVA) and polyethylene glycol (peg) to alumina slip casting product
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Date
2025-08-01
Authors
Yong, Jing Rui
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Abstract
Alumina slip casting is a conventional shaping method that able to produce complex geometries with dimensional accuracy which is suitable to be used for furnace tubes and thermocouple protection tubes. Since there is limited research studies on the impact of lower molecular weight of additives to slurry’s rheological and final sintered product characteristics, low molecular weight PVA (binder) and PEG (plasticizer) were used in this study. The objective of this research is to evaluate the effects of varying concentrations of PEG and PVA and determine the optimal formulation that
correlates between rheological of alumina slurry and characteristic of sintered alumina product. In this study, PVA (31000g/mol to 50000 g/mol) and PEG (1500 g/mol) were used at different concentration which is from 1.0 wt% to 4.0 wt% to evaluate their influence on slurry’s viscosity, casting time pH and sintered alumina product’s shrinkage measurement, density, porosity and flexural strength. The slurry formulations were prepared by using ball milling and slip cast into molds, followed by drying and sintering at 1650 °C. Based on the results obtained, viscosity of the slurry decreases as increasing the concentration of PVA. In contrast, the viscosity of slurry was reduced when the concentration of PEG increases. For casting time measurement, the lower the concentration of PVA and PEG, the greater the wall thickness formation. The optimal concentrations of PEG and PVA was sample S6 (1 wt% PEG + 1 wt% PVA) was determined as the optimal formulation since it shows the highest flexural strength (38.80 MPa), bulk density (3.88 g/cm³), the lowest porosity (3.05%), and rapid wall formation with sufficient shape retention and better appearance.