Expandable polystyrene block molding

Expanded polystyrene (EPS) headboard insulation is produced with expandable polystyrene beads. These beads are produced by impregnating with 5-8% pentane and sometimes with flame retardants such as hexabromocyclododecane or pentabromomonochlorohexane. The beads are preexpanded by fabricators with steam or vacuum and then allowed to age. The preexpanded beads are fed to the steam-heated block molds where further expansion and fusion of beads take place. The molded blocks are then sliced into various sizes needed for specific applications after curing. Block densities range from 13 to 48 kg/m (0.8-3 Ib/ft ), with 24 kg/m (1.5 Ib/ft ) most common for cushion packaging and 16 kg/m (1.0 Ib/ft ) for insulation applications. 

Block copolymers themselves are also finding rapidly expanding applications on an industrial scale. A sandwich copolymer (triblock) with an elastomeric core (polybutadiene, polyisoprene, etc.) and plastomeric ends (polystyrene, etc.) represents a physically vulcanizing rubber (plastomeric elastomer). It can be processed above the glass transition temperature of the plastomeric blocks by work-efficient technologies (injection molding, extrusion, etc.). At temperatures below the Tg of the plastic blocks, the copolymer behaves as vulcanized rubber. 

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