Certain properties like and hardness with impact polystyrene. The shock resistance or toughness of impact polystyrene may be varied by increasing the content of rubber in the material, and often these materials are further classified as intermediate-impact, high-impact, and super-impact polystyrene. General-purpose polystyrene is a rigid, crystal clear plastic. Polystyrene has been used by dispensing pharmacists for years for containers for solid dosage forms because it is relatively low in cost At present, polystyrene is not useful for The plastic high water vapor transm (in comparison to high-density polyethylene) as well as high oxygen permeability. Depending on the methods of manufacture and other factors, polystyrene containers are easily scratched and often crack when dropped. Polystyrene will build up static charge. Polystyrene has a low melting point and therefore cannot be used for hot items or other high-temperature applications. Polystyrene is resistant to acids, except strong acids, and to alkalies.