Available in both solid and foam forms, polystyrene is known for its ease of molding and clarity. Solid polystyrene is used for products like CD cases and plastic cups, while expanded polystyrene (EPS) foam is widely used for insulating and packaging materials due to its excellent thermal insulation properties. However, its brittleness and environmental impact, particularly in marine pollution, have raised concerns, leading to increased regulations and development of more eco-friendly alternatives.