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 An innovative high-performance material: biofibers made from green lacewing silk
20.01.2017 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

nachricht Treated carbon pulls radioactive elements from water
20.01.2017 | Rice 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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>