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Home  > Raw materials & technologies  > Applications  > Protective & Marine coatings  > Macroporous polystyrene foam under control

Wednesday, 16 October 2019
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Raw materials & technologies, Applications, Protective & Marine coatings

Macroporous polystyrene foam under control

Friday, 17 February 2012

Isolation of buildings with polystyrene is usual. A new method for the controlled production of structured foam is published. The technique is based on the polymerisation of foamed emulsions of oil in water containing styrene, water, glycerol, and sodium dodecylsulfate.

Know-How gained for the structural foam control, SEM image, scale bar 250 µm  Source: Wiley

Know-How gained for the structural foam control, SEM image, scale bar 250 µm  Source: Wiley

Isolation of buildings with polystyrene is usual. A new method for the controlled production of structured foam is published. The technique is based on the polymerisation of foamed emulsions of oil in water containing styrene, water, glycerol, and sodium dodecylsulfate.

After addition of a photoinitiator the mixture is polymerised with UV light and the foam structure of the precursor is transferred to the polymer. The resulting materials display densely packed cells with windows between adjacent pores. The property profile of a foam depends on the number and size of the pores, whether the pores are closed off or connected, and the thickness of the polymer supports between the pores. "The high complexity of conventional production processes, which generate foams from polymer melts and blowing agents, makes control over the morphology and properties of the product a big challenge,” explains Prof. Cosima Stubenrauch, researcher at the University of Stuttgart.

After the first emulsifying in an aqueaous phase, the emulsion is stabilised with an anionic surfactant and foamed with nitrogen. This forms bubbles surrounded by tightly packed drops of emulsion. In the third step, the  polymerisation is initiated by irriadiation with UV light. The drops of emulsion dissolve away, while the structure of the foam—that of the template—is maintained.

The resulting polymer foams contain pores that are partially interconnected through "windows”. "While the high density of the polymer and the strong bonds provide good mechanical stability, the presence of the windows allows air, fluids, or other materials to flow through the foam,” says Stubenrauch. "Control over these properties is desirable for many applications, such as supports, filter agents, or biologically inspired scaffolding. This production technique is simple and versatile and represents a highly promising alternative to other template-based synthetic methods.”

Contact Prof. Cosima Stubenrauch at the University of Stuttgart, Institute for physical chemistry: cosima.stubenrauch@ipc.uni-stuttgart.de

Provided by Wiley

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