Expanded polystyrene sheets, packing peanuts, foam-in-place and foam-in-bag, and polyethylene sheets are all types of packing foam. Both expanded polystyrene and packing peanuts are made from polystyrene. Foam-in-place and foam-in-bag are made from polyurethane. Polyethylene is available in flexible sheets. Each of these packing foams is best suited to protect as specific type of product during shipping.

Expanded polystyrene (EPS), also called beadboard, is often referred to as Styrofoam™. However, Styrofoam™ is a trademarked product of the Dow Company. As such, it should not be confused with other EPS products. EPS is a lightweight, rigid, plastic packing foam that is made by expanding small polystyrene beads. It has only minimal cushioning properties and is best used when packaging lightweight items.

Packing peanuts, also referred to as loose fill, are small, lightweight, peanut shaped packing foam that are designed to interlock when compressed and flow freely when loose. The interlocking shape allows it to cushion the products being shipped. As such, they are used to fill up empty spaces around products being shipped. Packing peanuts cannot keep products in place when they are shipped, and so they should not be used with products that can shift and move in transit. The peanuts can generate static electricity so they should not be used when shipping electronic equipment.

For more shock absorbing power, polyurethane is a versatile packing foam option. Polyurethane can be flexible or rigid and can be made as sheets, as foam-in-place, or as foam-in-bags. When made into sheets, this packing foam can either be made into a soft, flat sheet or into an egg-crate looking sheet. The egg-crate design allows the polyurethane to interlock with itself and provides a cushion for the product to be shipped. The foam also has good resiliency and absorbency and is ideal for packaging light products.

Foam-in-place and foam-in-bag packing foam are used when a snug fit around the product is desired. In these two options, two chemicals are sprayed into the packaging where they react and expand into the polyurethane foam. With foam-in-place, the chemicals are sprayed around the product. It then expands and molds itself into the product’s shape. The polyurethane in foam-in-bags is sprayed into a bag. The bag is then placed around the product where it expands to provide a snug fit.

Furniture is often wrapped using polyethylene. Polyethylene can also be made into an anti-static packing foam which makes it ideal for shipping electronics and computer parts. It is also mold and bacteria resistant. A unique property of polyethylene is that it is tear-resistant in transit but can be easily ripped by human hands. It is also shock absorbent and shatterproof, does not produce dust, and is chemical- and grease-resistant.