Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wood: Simplified Method Shows Complex Structure

20.09.2005


Cross-section of a mechanically isolated wood fibre by electron microscopy.


Mechanically-isolated wood fibres show several different properties in comparison to chemically-isolated fibres. This is one of the most recent results of a project funded by the Austrian Science Fund FWF at the University of Natural Resources and Applied Life Sciences, Vienna. The project yields significant findings on the structural changes in wood fibres after exposure to moisture and tension. The current results are important for both the structural analysis of wood as well as for the investigation of innovative applications for this classic material.

Wood is one of the most common and versatile natural organic materials. It harmoniously combines high strength with high deformation capability. How these seemingly contradictory properties may be explained, is a topic of today´s wood research. For the analysis of wood’s numerous properties, individual wood fibres had been isolated by means of a chemical procedure until now - although researchers have suspected for a long time that this chemical procedure leads to changes in wood so that scientific results might be doubtful.

In response to this problem, scientists at the University of Natural Resources and Applied Life Sciences, Vienna developed an alternative isolation method for wood fibres. Fibres are isolated from wood in a mechanical procedure using fine tweezers. "We have thus succeeded in isolating wood fibres whose cell walls are not changed or destroyed by chemical substances", says Prof. Stefanie Stanzl-Tschegg at the Institute of Physics and Material Sciences when explaining the advantages of the method. "If we now compare mechanically isolated wood fibres with those that have been traditionally isolated with chemicals then we are able to better understand the weaknesses of individual methods. In this way, we obtain much new information about the structure and properties of wood." Additionally, the scientists were able to show that the mechanical isolation method is also capable of isolating single fibres of other natural materials such as hemp or flax in a much better way than previously possible.



Wet & Dry

An important property that Prof. Stanzl-Tschegg and her colleagues were able to elucidate through their latest findings was the drying behaviour of wood. Previous projects on this topic with chemically-isolated wood fibres showed that fibres twist in an anti-clockwise direction as a result of the drying procedure. Responsible for this phenomenon are spiral-shaped structures in the cell walls of wood fibres. These are formed by so-called cellulose fibrils, which are embedded parallel to each other, strengthening the material. However, tests carried out by the team of Prof. Stanzl-Tschegg indicated that wood fibres twisted much less during drying when mechanically isolated. By means of special microscopic methods the researchers analysed the matrix consisting of the complex molecules lignin and hemi-cellulose. Contrary to the chemically isolated wood fibres, this matrix remains intact in mechanically-isolated wood fibres where it encompasses individual cellulose fibrils. Hence the matrix resembles a corset that lends stability to wood fibres in wet condition by counteracting distortions during the drying process.

Tension & Pressure

This result falls in line with a remarkable list of fundamental findings on the natural material of wood by Prof. Stanzl-Tschegg and her team. Similarly, they had succeeded in detecting yet another functional feature of wood fibres: a molecular mechanism within the wood fibres works like a Velcro connection. When cellulose fibrils deform as a result of tension or pressure, their bonds disconnect from the matrix of lignin and hemi-cellulose and consequently allow for deformation of the wood. As soon as the stress is released, however, the bonds lock-in at the new position and continue to maintain the original stiffness of the material - a property that had so far been associated with metallic materials rather than with wood.

It is the discovery of such previously unknown properties of the traditionally proved natural material of wood that permits its specific and secure use in new applications. In that manner, this material research project funded by the Austrian Science Fund FWF also contributes to securing the future of a significant branch of industry in Austria, a country rich in forests.

Till C. Jelitto | alfa
Further information:
http://www.fwf.ac.at/en/press/wood.html

More articles from Agricultural and Forestry Science:

nachricht Climate change, population growth may lead to open ocean aquaculture
05.10.2017 | Oregon State University

nachricht New machine evaluates soybean at harvest for quality
04.10.2017 | University of Illinois College of Agricultural, Consumer and Environmental Sciences

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Electrode materials from the microwave oven

19.10.2017 | Materials Sciences

New material for digital memories of the future

19.10.2017 | Materials Sciences

Physics boosts artificial intelligence methods

19.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>