Polystyreen

Polystyrene, often abbreviated as PS, is a synthetic polymer derived from the monomer styrene. It is a thermoplastic material, meaning it becomes moldable when heated and solidifies upon cooling. The polymer chain consists of repeating styrene units (a benzene ring bonded to an ethylene group), yielding products that range from rigid solids to light foams depending on formulation and processing.

Polystyrene is produced in several commercial grades. General purpose polystyrene (GPPS) is a transparent, rigid plastic used in packaging, consumer electronics housings, and office supplies. High-impact polystyrene (HIPS) blends GPPS with polybutadiene rubber to improve impact resistance. Foam variants include expanded polystyrene (EPS), which forms by expanding beads with blowing agents to produce lightweight insulation and cushioning, and extruded polystyrene foam (XPS), which is denser and offers better moisture resistance.

Key properties include a glass transition temperature around 95–100°C, brittleness at room temperature for GPPS, good electrical insulation, low density, and relatively good chemical resistance to many solvents but not to aromatic solvents. It is flammable and can emit toxic fumes if burned. Styrene monomer exposure and processing conditions are regulated due to health concerns. Recycling is possible, but PS is often challenging to collect and process; codes indicate resin identification code #6.

Uses and disposal: PS is widely used in packaging, food-service ware, insulation, and consumer goods. Environmental considerations include persistence in the environment and potential litter; recycling programs and alternative materials are used to mitigate waste. The balance of performance, cost, and environmental impact continues to shape its use, with ongoing development of more recyclable or eco-friendlier styrene-based materials.