Polystyrene Foams: Materials, Technology, and Applications

Polymer foams have become almost ubiquitous in their wide range of applications in different sectors of day-to-day life, and in industries. In particular, foams made from the inexpensive aromatic hydrocarbon polymer, polystyrene, hereafter referred to as polystyrene foam, are among the most widely used polymer foams around the world, itself accounting for millions of tons of plastic produced each year. There are several different kinds of polystyrene foam currently in use, and quite a variety of ways of fabricating them; the most popular kinds of the foam include extended (EPS), and extruded polystyrene (XPS). The applicability of a particular kind of polystyrene foam depends on its structure alongside its overall density. Owing to their low thermal conductivities and mechanical strength, polystyrene foam finds extensive use in the insulation industries, e.g., they are very popular as building insulation materials. Furthermore, foams that are incorporated with different other materials, such as graphite, often exhibit an enhancement in their insulation properties and mechanical strength. One of the highly popular use of polystyrene foams is in the manufacture of disposable food containers. These foams also have excellent damping properties, which allows them extensive usage as packaging materials. Despite their popularity, none of these foams are biodegradable and hence, have become a major environmental pollutant. In this chapter, we present an overview of polystyrene foam, its history and varieties, namely Expanded Polystyrene and Extruded Polystyrene, the techniques of their fabrication, their different properties, applications, and environmental impact and mitigation. We will also extensively cover much of the recent relevant research that has been dedicated to the improvement of the properties of polystyrene foams.