Development of novel polystyrene composite beads for defect-free lost foam casting

The wider adoption of the Lost Foam Casting (LFC) process by the foundry industry has been impeded by the occurrence of fold defects. It is well known that a new foamed polymer, which degrades with less thermal energy (or less endothermic) and produces fewer gaseous pyrolysis products, may be a solution to fold defects. Hence, this pioneering research was an attempt to develop novel polystyrene composite beads for the LFC process through suspension polymerization. Low molecular weight polystyrene composite beads were initially produced, and the presence of the additives inside these beads was confirmed by Energy Dispersive X-ray (EDX) analysis. High molecular weight polystyrene composite beads were then produced. The thermal properties of these low and high molecular weight beads were then produced. The thermal properties of these low and high molecular weight beads were studied using advanced characterization techniques such as a thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). It was found that these polystyrene composite beads degrade faster and at lower onset temperatures of degradation than the unmodified polystyrene beads in the LFC industry to reduce casting defects.