Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-Strengh Materials from the Pressure Cooker

06.05.2014

A Surprise in Materials Chemistry: At Vienna University of Technology, materials for lightweight construction, protective clothing or sports equipment can be produced at high temperatures and high pressures. This process is faster, better and more eco-friendly than other techniques.

The earth’s crust works like a pressure cooker. Minerals typically do not form under standard conditions, but at high temperatures and pressures. However, an environment of extreme heat and pressure has been considered to be absolutely unsuitable for organic molecules.


„Microflowers" made of PPPI, the world's most mechanically stable organic polymer. The blossoms are approximately five microns wide.

Scientists at Vienna University of Technology found out that under such seemingly hostile conditions, organic materials with remarkable material properties can be synthesized – for instance Kevlar, an extremely versatile high-performance material.

Steam Instead of Toxins 
It seems counterintuitive: one might expect large, complex organic molecules to be destroyed by heat and high pressure. But at 200 degrees Celsius and 17 bars, Miriam Unterlass and her team at TU Vienna have synthesized organic polymers, which are usually extremely hard to create and require highly toxic additives.  Instead of hazardous solvents, the team at TU Vienna uses nothing but harmless water vapour, making the new method extremely eco-friendly.

The principle of so-called “hydrothermal synthesis” is well known from geology. Many gemstones only form deep down in the ground, in high-pressure water reservoirs. In contrast to these inorganic minerals, which are often mainly made up of silicon and metal ions, many high-performance materials are organic. They primarily consist of carbon and hydrogen.

Kevlar is an example of such a high-performance polymer. It is extraordinarily robust and it is used for protective clothing or for construction elements that are supposed to withstand extreme strain. Such materials also play an important role in aircraft construction, because they are much lighter than any metal parts with comparable properties. Organic high-performance polymers are huge organic molecules with a very stiff structure, kept in place by a multitude of bonds between the atoms.

Extremely Durable, but Hard to Synthesize
Such durable materials, however, are very hard to synthesize: “We have to deal with two contradictory requirements”, Miriam Unterlass explains. “On the one hand, we want to have rigid materials which do not dissolve and do not melt even at high temperatures. On the other hand, this means that we cannot just dissolve and then crystalize them, as we would if we were dealing with simple rock salt, for example.” The technique developed at TU Vienna works quite differently: the polymers are forming and are crystallizing simultaneously, uniquely supported by hydrothermal conditions.

There are many advantages to this procedure: no dangerous byproducts are created, the energy consumption is dramatically reduced, and the synthesis in the pressure reactor is much faster than it would be using any other techniques. Also, the final product is better: “Our method yields materials with higher crystallinity, which further improves the mechanical rigidity”, says Miriam Unterlass.

Looking Inside with Infrared Light
Fine-tuning of the process is complicated, however. Mass and energy transport inside the reactor have to be very well known to understand exactly what is taking place. Of course the pressured rector cannot just by opened during the reaction to see what is happening. Therefore, a special infrared probe is used, which can easily withstand the extreme conditions inside the reactor. “When we put the probe inside the reactor, we can follow in real-time what happens inside, without having to draw any samples”, Unterlass explains.

With the new high-temperature IR-probe – it is one of only two such devices worldwide –  it will become easier to develop even more synthetic techniques. The team has plenty of ideas: “There is a plethora of organic molecules which promise great material properties if we manage to polymerize them”, says Miriam Unterlass.

Further Information:
Dr. Miriam Unterlass
Institut für Materialchemie
Technische Universität Wien
Getreidemarkt 9, 1060 Wien
T: +43-1-58801-165206
miriam.unterlass@tuwien.ac.at

Florian Aigner | Eurek Alert!
Further information:
http://www.tuwien.ac.at/en/news/news_detail/article/8695/

More articles from Materials Sciences:

nachricht Machine-learning predicted a superhard and high-energy-density tungsten nitride
18.07.2018 | Science China Press

nachricht In borophene, boundaries are no barrier
17.07.2018 | 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: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>