PS (Polystyrene) Overview Readily recognizable due to its range of everyday uses such as CD cases, pens, food packaging, and packaging foam. PS faces competition from paper, glass, wood, PP, PVC, and ABS. The three main types are: general purpose (crystal) PS, high impact PS, and polystyrene foam. Strengths Cheap. Low mold shrinkage allowing for … Continue reading PS (Polystyrene)