Additive stops aging in super glassy polymer membranes
Putting a stop to aging has now been made possible for highly porous polymer membranes whose efficiency in the separation of gases falls off fast when parts of their polymer chains rearrange, as so do their pores.
In the journal Angewandte Chemie , a team of Australian and American researchers has now introduced a method for preventing this relaxation of the polymer chains: special porous particles made of an aromatic framework incorporate the polymer chains and hold them in their original position.
Separation processes like purification and adsorption are especially energy-intensive procedures; it is thus correspondingly important to find alternatives to replace existing technologies.
One possible approach is gas separation using polymer membranes. The theory behind this separation technique is that different gases pass through the membrane at different rates. This allows for the separation of CO2 from nitrogen, for example, which is relevant for carbon capture from flue gases. Currently, liquid absorbents that operate in a batch rather than continuous process are typically used.
The polymer membranes used must be extremely porous, so that as much of the surface area as possible is accessible to the gas molecules. It is no problem to produce highly porous membranes by using the appropriate “molds”.
However, any celebration of the high separation performance of these super glassy membranes, as they are known, does not last long as the membranes “age”. Despite the rigid state of the polymer, individual polymer segments are not fully “frozen” into position but can move to some extent. For thermodynamic reasons, the polymer chains attempt to stay as evenly distributed as possible.
This also causes them to fill the empty space within the pores. Because of their residual mobility, the polymer chains “relax” little by little, slowly reducing the free volume of the pores. The separation performance of the membrane falls off correspondingly. It has not previously been possible to effectively halt this process.
Led by Matthew R. Hill and Richard D. Noble, a team from the Division of Materials Science and Engineering at the Commonwealth Scientific and Industrial Research Organization (CSIRO) and the University of Colorado (USA) has now developed a method that prevents aging of super glassy membranes.
The trick is to include a specific additive during production of the membranes. The additive consists of porous microparticles made of a special three-dimensional framework of aromatic compounds and carbon atoms. The microparticles are strung along the particle chains like pearls on a string. This causes the chains to be “frozen” in place.
The pores remain as open as they were when first manufactured and the membrane does not age. As a side effect, the porous aromatic microparticles improve the ability of the membranes to separate nitrogen and carbon dioxide up to three-fold.
About the Author
Dr. Matthew Hill is a senior research scientist with the CSIRO, Australia’s national science agency. He specialises in ultraporous materials with applications in separation, storage and triggered release. He is a 2014 awardee of the MIT Technology Teview ‘Innovators under 35’ award for the South-East Asia region.
Author: Matthew R. Hill, CSIRO Division of Materials Science and Engineering, Clayton South (Australia), https://wiki.csiro.au/display/MEWE/Matthew+Hill
Title: Ending Aging in Super Glassy Polymer Membranes
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201402234
Dr. Matthew Hill | Angewandte Chemie
Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology
Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
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...
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...
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...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences