Expanded polystyrene cores

Panels in sandwich of expanded polystyrene core with composite skins. 

Major structural applications for RHMU include the assembly of large panels for recreational and commercial vehicles [43], the bonding of steel panels with an expanded polystyrene core for the production of insulated garage doors, and the lamination of polyvinyl chloride sections for window construction [44]. There are also automotive applications snch as laminating dashboards, interior seating and trim [45]. 

Roofiag panels have been made from polyisocyanurate foams, both foam- and felt-reiaforced with glass fiber. PhenoHc resias are used especially for decorative laminates for paneling. The substrate may be fiberboard or a core of expanded polystyrene beads. In one case the beads are coated with phenoHc resia, then expanded ia a mold to form a stmctural foam panel. 

The foams, marketed by Rohm as Rohacell, are stable at room temperature to hydrocarbons, ketones, chlorinated solvents and 10% sulphuric acid. They may be used under load at temperature up to 160°C. Uses quoted for these materials include bus engine covers, aircraft landing gear doors, radar domes, domes, ski cores and tennis racket cores. Their potential is in applications demanding a level of heat deformation resistance, solvent resistance and stiffness not exhibited by more well-known cellular polymers such as expanded polystyrene and the polyurethane foams. 

Expandable polystyrene EPS is a modified PS prepared as small beads containing pentane gas which, when steamed, expand to form lightweight, cohesive masses for forms used to mold cups and trays, package fragile products for shipment, etc. Similar dimensionally stable forms molded from EPS are used as cores for such products as automobile sun visors with surface overlays, etc. 

Expanded polystyrene foam known commercially as Styrofoam, is sold in blocks and sheets for building model airplane wing cores.These are available from hobby shops or by mail from model supply houses. Numerous shapes including balls,cones,rings etc.are sold for flower decgrating and general craft use. These are found in any variety store. Fpam packing containers may be picked up from department stores,usually for free. 

The combined use of continuous-glass-strand mat as a core material and uniformly and monoaxially aligned continuous-glass fiber as the surface material has also been proposed (5, 25). The incorporation of expanded polystyrene copolymers into composites was proposed for shock-absorbing composites, such as bumper beam cores, knee bolsters, etc. (17, 18). 

Cellular cellulose acetate is made in a maimer somewhat similar to the one used in the production of expanded polystyrene. It is relatively the same density of expanded polystyrene however, the useful temperature range is extended up to 175°C. It also has somewhat better chemical resistance than polystyrene foam. Thus it is seen in many of the same applications as polystyrene foam where these additional properties are necessary (e.g., aircraft structure cores, flotation devices). Cellulose acetate foam is trademarked Strux (Aircraft Specialties Corp.). 

This simplification was used by Ottewill and Walker (7) in their study of the adsorption of a nonionic surfactant onto polystyrene latex in aqueous sodium chloride. In the case of carboxylated emulsion polymers, evidence from conductometric titrations suggests that the carboxyl groups are generally concentrated near the particle surface. The resultant model of an expanded particle is that of a hydrated acid-rich shell surrounding a compact polymer core. The hydrated shell may be viewed as a dilute polymer solution where the density is close to that of water, i.e., Pe= P0. With this assumption, Equation 1 reduces to the form ... 

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. 

These companies have created core capabilities in areas other than production. They have, for example, used superior deal-making and human resources skills to expand rapidly. Moreover, they have focused their businesses by acquiring and merging business units from less focused competitors. With these, they have built up powerful positions in product innovation or cost leadership - hke that of Nova, for example, in polystyrene. 

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