Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

All Foamed Up

07.02.2012
Synthesis of macroporous polystyrene through polymerization of foamed emulsions

Packaging, insulation, and impact protection are examples of commercial uses of polymer foams. Depending on the intended application, the properties required of these foams can differ greatly.


In the journal Angewandte Chemie, a team of German, Irish, and French researchers led by Cosima Stubenrauch at the University of Stuttgart has now introduced a new method for the controlled production of structured foams. Their technique is based on the polymerization of foamed emulsions of oil in water.

Not all foams are equal: a kitchen sponge, for example, is not the same as a piece of Styrofoam packaging. Different applications make different demands on a foam, which has led to efforts to control the properties of foams in a targeted fashion. In addition to a foam’s chemical composition, its structure also plays an important role. 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 Stubenrauch.

An alternative approach involves the use of microscopically small templates to force the foam into the desired structure. For example, tiny droplets of water can be finely dispersed (emulsified) in a solution of monomer, then removed after the polymerization is complete. Another process uses particles to stabilize air bubbles in the reaction mixture.

Stubenrauch’s team has now introduced a new concept for the synthesis of macroporous polystyrene foams: the polymerization of foamed oil-in-water emulsions. Styrene (the “oil phase”) is first emulsified in an aqueous phase. Afterward, the emulsion is stabilized with an anionic surfactant and foamed with nitrogen. This forms bubbles surrounded by tightly packed drops of emulsion. In the third step, the polymerization 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.”

About the Author
Dr. Cosima Stubenrauch is Full Professor and head of the chair “Physical Chemistry of Condensed Matter” at the University of Stuttgart, Germany. She has been working on colloids and interfaces for 18 years. She is also docent at the KTH Royal Institute of Technology, Stockholm, Sweden and the recipient of 11 awards among which the Nernst–Haber–Bodenstein Award 2007.
Author: Cosima Stubenrauch, Universität Stuttgart (Germany), http://www.ipc.uni-stuttgart.de/AKStubenrauch/group/staff/stubenrauch/
Title: Synthesis of Macroporous Polystyrene by the Polymerization of Foamed Emulsions

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201107806

Cosima Stubenrauch | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Materials Sciences:

nachricht Gelatine instead of forearm
19.04.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Computers create recipe for two new magnetic materials
18.04.2017 | Duke University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

Im Focus: Quantum-physical Model System

Computer-assisted methods aid Heidelberg physicists in reproducing experiment with ultracold atoms

Two researchers at Heidelberg University have developed a model system that enables a better understanding of the processes in a quantum-physical experiment...

Im Focus: Glacier bacteria’s contribution to carbon cycling

Glaciers might seem rather inhospitable environments. However, they are home to a diverse and vibrant microbial community. It’s becoming increasingly clear that they play a bigger role in the carbon cycle than previously thought.

A new study, now published in the journal Nature Geoscience, shows how microbial communities in melting glaciers contribute to the Earth’s carbon cycle, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

New quantum liquid crystals may play role in future of computers

21.04.2017 | Physics and Astronomy

A promising target for kidney fibrosis

21.04.2017 | Health and Medicine

Light rays from a supernova bent by the curvature of space-time around a galaxy

21.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>