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 Complex tessellations, extraordinary materials
23.01.2018 | Technische Universität München

nachricht Thanks for the memory: NIST takes a deep look at memristors
22.01.2018 | National Institute of Standards and Technology (NIST)

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Optical Nanoscope Allows Imaging of Quantum Dots

Physicists have developed a technique based on optical microscopy that can be used to create images of atoms on the nanoscale. In particular, the new method allows the imaging of quantum dots in a semiconductor chip. Together with colleagues from the University of Bochum, scientists from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute reported the findings in the journal Nature Photonics.

Microscopes allow us to see structures that are otherwise invisible to the human eye. However, conventional optical microscopes cannot be used to image...

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Enhanced ball screw drive with increased lifetime through novel double nut design

23.01.2018 | Machine Engineering

Optical Nanoscope Allows Imaging of Quantum Dots

23.01.2018 | Physics and Astronomy

Incentive to Move

23.01.2018 | Life Sciences

VideoLinks Science & Research
Overview of more VideoLinks >>>