As one of the most widely used materials in the world, we are surrounded and use polystyrene foam every day, often without realizing it. Packaging materials, foam cups, food trays, coolers, and toys are just a few of the polystyrene products we come across frequently. Polystyrene is also used in flotation, insulation, and construction devices, which makes it a ubiquitous material.
There are two main types of polystyrene foam, defined by the molding process, resulting in slightly different structural compositions. Expanded polystyrene foam, known as EPS, and extruded polystyrene foam, known as XPS, are both closed-cell foams with slightly different sensations, properties, and structures.
Polystyrene material is often called Styrofoam, that's wrong. Styrofoam is a brand and type of specialty polystyrene foam owned by the Chemical Company and is mainly used as insulation.
The most widely used variant of the two, EPS, is made by polymerization, in which a chemical reaction, a tiny sphere, expands significantly through heat and steam as it melts and joins together to form a solid material made of separate tiny foams. pellet form. . Therefore, EPS expansion can be up to 98 percent air, depending on the type. XPS foam is made through a slightly different process.
The polystyrene crystals combine with other chemicals and are fed to an extruder which produces a high level of heat and pressure that binds the materials together into a thick, liquid mass. In this state, it is sent through a matrix that forms its shape as it expands through contact with air and chemical reactions. The two materials can be made into large sheets or blocks to make materials such as insulation or packaging or pressed into shapes that make a finished product such as drinking glass.