Insulation Value

Many temperature sensitive pharmaceutical and medical products use EPS because comparable packaging materials can rarely offer the same level of thermal insulation.

Strongly relied upon in the food distribution industry, EPS is ideal for long distance shipment of perishable foods. EPS is highly resistant to heat flow. Its uniform, closed cellular structure limits radiant, convective and conductive heat transfer.

Water Absorption and Transmission

The cellular structure of molded polystyrene is essentially impermeable to water and provides zero capillary.

However, EPS may absorb moisture when it is completely immersed due to its fine interstitial channels within the bead-like structure. Vapor permeability is a function of both density and thickness. Generally, neither water nor vapor affects the mechanic al properties of EPS.

Chemical Properties

Water and aqueous solutions of salts, acids and alkalis do not affect molded polystyrene. Most organic solvents are not compatible with EPS. This should be taken into consideration when selecting adhesives, labels and coatings for direct application to the product. All substances of unknown composition should be tested for compatibility.

UV radiation has a slight effect on molded polystyrene. It causes superficial yellowing and friability, but does not otherwise affect physical properties.

Expandable Polystyrene Advantages