Polystyrene nucleating agent

Effective nucleating agents for extruding polystyrene foam sheet include the following (47) ... 

A wide variety of polymers can be foamed, including the polymethanes, polyisocyanurates, PVC, polystyrene, ABS, polycarbonate, PET, PBT, polyamides, PPO, EVA and the polyolefins. Other additives required for the foaming process besides blowing agents may include foam nucleating agents, stabilisers, surfactants, plasticisers, colourants, flame retardants and particulate fillers. 

An extraded foam is based on at least one polymer selected finm polysuUbne or polyether sulfone, polystyrene, or a copolymer produced from styrene and comprises at least one nucleating agent based on a wax (polyethylene wax) or on an oligomer containing epoxy groups (nucleating agent concentration is 0.5-1%)."... 

Depending on the ciystallization conditions, sPS chains can ciystalUze into at least four ciystalline modifications (a, p, y, and 8 forms). The mechanical strength of sPS samples depends on the crystalline modification and the degree of ciystalUnity. Graphene nanosheets acted as P-nucleating agent for syndiotactic polystyrene. Carbon nanotubes increase peak crystallization temperature by 14°C. ... 

Nucleating agent, cell-control These agents promote symmetrical, cohesive expansion of cells within foamed polyurethane and polystyrene plastics also to a limited extent in polyethylene and polypropylene plastics. 

Numerous attesnpts have been made to predict the effectiveness of potential nxacleating agents with particular attention having been paid to the crystallisation of isotactic polypropylene, isotactic polystyrene (6), polyethylene (2 9) ard poly(ethylene terephthalate) (10,11). However, little can be concluded about the fundamental mechanism of heterogeneous nucleation, or the propeirties of effective nucleating agents. 

Nucleating agent—polystyrene foam South Africa 5,187 1969 Dow Chemical... 

Figure 12.6. Possible applications of falling paper principle, (a) Dynamic kite made from expanded polystyrene bead material with S-shaped rotor wing, (b) Radar target consisting of pieces of aluminum foil rotating and translating in random directions, (c) Means for economic use of nucleating agent in a cloud seeding operation, (d) Auxiliary power driven Flettner rotor ship, (e) Axial view of Savonius wind driven rotor, (f) Sailboat with two collapsible nylon sails.

These additives are used to overcome the inherent brittleness of polymers such as polystyrene, polypropylene, and Terylene. The additives are incorporated into the polymer during manufacture. Pigments, extenders, fillers, nucleating agents, hydrocarbon oils, waxes and rubbers are all used as a means of improving the impact strength of these polymers. 

---