Polystyrene is an aromatic polymer which is produced either in solid form or as a foam. Polystyrene is a synthetic resin which is inexpensive. Polystyrene is a widely used plastic due to its relatively low melting point. It is also used in packing foodstuffs like peanuts and also tumblers, bottles, CD cases, and lids. It has a poor barrier to oxygen and water vapour. This material flows when heated and becomes rigid when cooled. It exist as solid only ion room temperature.