Poly(phenylethene), commonly known as polystyrene, is the third most important polymer, in terms of amount made from ethene. Its physical properties can be adjusted to suit a range of everyday uses.Techniques have been developed which increase its mechanical strength, its ability to absorb shock and its thermal insulating properties.

The largest use for poly(phenylethene) is for packaging, particularly for foods such as poultry and eggs, for cold drinks and take-away meals. It is also used in making appliances, including refrigerators, microwaves and blenders.  It is the leading choice for jewel boxes (cases for CDs and DVDs) and is also widely used for its insulating properties.