Particle Foam Based on Expandable Polystyrene EPS

Foamable polystyrene beads are generally produced by two basic processes  

incorporation of a blowing agent during the extrusion process of bulk polystyrene, with the polymer strands quenched in a water bath to avoid foaming and consequent strand cutting. 

The resulting raw material, in the form of beads or granules, is called expandable polystyrene (EPS). The usual procedure is for the EPS beads or granules to be prepared in one location and transported to other locations, where they are expanded and/or molded into their final forms. This process has inherent advantages the costs of shipping the voluminous foam is minimized and intricate molding shapes can be molded directly without postprocessing. 

The expandable polystyrene particles, based on suspension polymerization, are converted into foam in three steps pre-foaming, temporary storage and final 

Modern Styrenic Polymers Polystyrene and Styrenic Copolymers. Edited by J. Scheirs and D. B. Priddy 2003 John Wiley Sons Ltd 

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