EmpaNews April 2012

Laser-poweredexhaust lab 06

Liquid-filledfibre 04

Magic stuff fromwooden fibres 22

Magazine for Research, Innovation and Technology TransferVolume 10 / Issue 36 / April 2012

EmpaNews

Wood – a sustainable resource

02 // Editorial

Research for medium-sized companiesExhaust flow lab helpsclean up diesel fumes 06

“Hands on wood” –for 75 years

This is how long Empa has been conducting wood re-search. Humanity, of course, has been using thisversatile material for a little while longer. Amazing

things have been built from it – such as the pile-dwellingsfrom the Stone and Bronze Ages that are mainly found inthe Alps or the recently discovered, nearly 4,500 years old“wooden twin” next to the famous circle of stones in Stone-henge. Other creations are more notorious, such as theVasa, an impressive Swedish galleon from the time of the

Thirty Years’ War that failed to travel evenone nautical mile on its maiden voyage in1628 before a gust of wind caused it to cap-size (without making any contact with theenemy). A fate that can hardly be attributedto the construction material.

Despite (or perhaps expressly because of)this long history, wood is a material with abright future. This is reflected by the NationalResearch Programme “Resource Wood” (NRP66) that was launched at the beginning of theyear and, with 18 million Swiss francs over

five years, is one of the highest-funded NRPs ever. Thiscomes at just the right time, since Swiss forests are under-used and over-aged. What’s more, wood is a renewable rawmaterial that does not have to be imported. At the core ofNRP 66 is the optimization of the value chain forest – wood– chemistry – energy as well as (in the long run) the re-placement of the current petrochemistry with lignochem-istry (from the Latin “lignum” for wood).

And in order to ensure that the acquired knowledge isalso employed in practice as fast as possible, NRP 66 hasjoined forces with CTI, the Swiss government’s innovationpromotion agency. Companies, especially SMEs, as well asindustry associations are welcome to join from the very be-ginning and should thus ensure an efficient knowledge andtechnology transfer. This is all very much in line with thespirit of Empa, upon whose initiative NRP 66 was created.The current “Focus” paints a portrait of the diverse researchactivities of Empa concerning the topic of wood.

Enjoy reading!

Michael HagmannHead Communications

Cover

Glued laminated wood, successfullypatched with carbon fibres: Productengineer Annika Baier and Empaproject leader Robert Widmann aredelighted at the end of the hydraulicbending test. Engineering student RomanFrei feels the crack in the beam again.

Contents // 03

Wood fibres as magic ingredientNanofibrillated cellulose replacesaluminium in Tetra Pak 22

Learning from natureIngo Burgert knows howtrees “tick” 19

Nobel Prize verified100-year-old crystals revealall under X-ray 08

Research and development04 The garden hose fibre Lightweight summer jacket and bullet-proof vest in one – is that possible?

06 Operation Cleanup How laser technology helps to clean diesel exhaust

08 New insights from old samples What did 1913 Nobel Prize winner Alfred Werner know?

Knowledge and technology transfer11 Cooling agents heat up climate CFC substitutes are strong greenhouse gases

12 Wheelchair ergonomics Lack of posture change causes problems. Now help is at hand

13 While you were sleeping Monitoring system for bedridden persons takes the strain off carers

Focus: Wood research

14 The National Research Program “Resource Wood” (NFP 66)

16 Boulevard of broken beams Glued laminated wood in the hydraulic press – an endurance test

19 “Wood has many advantages.” Interview with Ingo Burgert, professor for wood-based materials

22 Wooden wonder from the pot Nano-fibrillated cellulose can protect wood from the weather

24 Biologically refined Enzyme treatment produces self-adhesive wood chips – and much more

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PublisherEmpaÜberlandstrasse 1298600 DübendorfSwitzerlandwww.empa.ch

Text & DesignCommunication

ContactPhone +41 58 765 47 [email protected]

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ISSN 1662-7768

04 // Research and development

The garden hose fibre Protective clothing is a must in many areas nowadays: be it in sport,for transport or in professions such as the police force and the firebrigade. However, the protection is often heavy and stiff, and restrictsthe wearer's freedom of movement. A research team at Empa isdeveloping a fibre that does not hinder slow movements, but stiffensup quickly after sudden shifts in position or impacts, thereforeproviding the body with the necessary protection.

TEXT: Nicole Döbeli / PICTURES, ILLUSTRATION: Empa

One possibility would be to designthe safety clothing of the future likea warm chocolate cake: firm on the

outside yet soft on the inside. Or like acough sweet with a soft, syrupy core. Thisis exactly what Empa researcher RudolfHufenus is trying to come up with. Not foranything to eat, however, but in the form ofa very special type of fibre. Its liquid coreconsists of a unique fluid that is soft orhard, depending on requirements: It re-mains liquid when stress levels are low, butbecomes as hard as rubber when force issuddenly applied. Substances like this,known as dilatant fluids, are the key forHufenus’ project.

The basic idea of the “Rheocore” pro-ject that is being funded by the Swiss Nation-al Science Foundation is to spin a hollowpolymer fiber containing a dilatant fluid. Ifthe filament kinks or bends, the fluid insideis squeezed through narrow passages in thefibre’s interior channels. The dilatant fluidreacts to this sudden shearing force andhardens, which stiffens the filament andconfines the movement. However, slowmovements are still possible because thefilling maintains its low viscosity. Hufenuswants to use this feature to develop a fibrethat will react dynamically to stress.

The idea of using dilatant fluids in tex-tiles is nothing new. For instance, there ismotor cycle clothing impregnated with dila-

tant fluids that stiffens in the event of an ac-cident. The fluids are also contained withinfoam pads. Other examples are closer tohome, for instance playthings such as “SillyPutty” found in many a child’s playroom.This silicone-based material looks and be-haves like plasticine as long as you work itslowly. But if you let it fall to the ground itbounces back like a rubber ball.

Liquid coreNo one, though, has dared to try this on fi-bres yet. To begin with, there’s the questionof how you would even go about producingsuch a filament. Hufenus turned to melt-spinning technology. Plastic granules arefilled into an extruder – a kind of wormdrive that heats, liquefies and pushes thegranules forward at the same time. A liquidplastic such as polyester is extrudedthrough a spinning nozzle at the end of thetube, and can then be wound up andcooled. The pilot system in the “AdvancedFibres” laboratory even has two extruders.With them core-sheath filaments can bespun from two different polymers.

But how do you make a fibre with a hol-low core? And how do you then fill it witha dilatant fluid? The pilot system at Empawas not designed for this type of experi-ment: the pressure in the spinning head canbe 100 bar or more, and the temperature inthe extruder up to 350 degrees C. Also, the

metal housing conceals what is going on in-side, which makes it impossible to developa completely new spinning process.

Thus the researchers needed a labora-tory model to gain a deeper understandingof the processes involved in the manufac-ture of a “fibre with filling”. Unlike a gardenhose, which you can simply connect to atap, it is virtually impossible to fill the fibrewith a liquid after it has been spun. There-fore, the liquid core has to exit from thespinning nozzle along with the solid poly-mer sheath, and the required cavity struc-ture must also be created at the same time.Empa researcher Laura Gottardo sim-ulates this process in a laboratoryexperiment. She combines two dif-ferent liquids such as water,ethanol, Vaseline or silicone invarious combinations in a glasstube at a pressure of about twobar, and a metal capillary per-forms the function of the spin-ning nozzle.

The different featuresand viscosities of the liquidsyield different results,which are recorded by ahigh-speed camera. Thedifficulty is to generate acavity with an appropri-ate shape. Individualseparated drops do not

1

Research and development // 05

Polymer A

Polymer B

Fluid

Fibre Cross Section

1Empa researcher Laura Gottardo simulates howthe fibres can be filled with liquid in a glass tube.The aim is to produce a string of connecteddroplets.

2This is what the cross-section of the fibre shouldlook like: an irregular cavity runs through theentire fibre and contains a dilatant liquid.Extremely fast movement makes the liquid harderand stiffens the structure. However, withslow movements the fibre remains pliable.

be flying blind, because we cannot observewhat happens inside”. Marco Dressler fromthe University of Massachusetts is in chargeof the calculations. He is going to create nu-meric models of the tests on a mainframe using the OpenFOAM software. Because ofthe complexity of the tests, it will take a good24 hours to perform the calculations for fourseconds’ worth of melt spinning the “filled fibre” – with eight processors.

The “Rheocore” project should come toa closure in 18 months’ time. By then theteam wants to have worked out the basics fora more advanced industrial project. Exactlyhow the fibres will ultimately be used is stillopen and depends on future industrial part-ners. Be it protective or sports clothing oreven medical applications – Hufenus and Co.are convinced that the potential is tremen-dous. //

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http://www.empa.ch/EN36-1For smartphone users: scan the QR code(e.g. with the “scanlife” app)

Video:Hightech-textilesfor hiking

work, because the dilatant fluid cannot bedisplaced when the fibre is subjected toload; the cavity must therefore run contin-uously through the entire fibre, much like acave system. However, even connectedchambers in the form of a “pearl necklace”are of no use, since the shape is too regular.Cavities that narrow and expand at irregu-lar intervals are ideal – this is the only wayto generate shearing forces in the fluid anduse them to stiffen the fibres.

It was the old saying “one man’s curseis another man’s blessing” that inspired the

researchers to try something new:drilling holes in the metalcapillary. This broughtabout turbulence be-

tween the sheath and the core fluid – pre-cisely the thing you’d have to avoid at allcost in “normal” melt spinning.

“Organ pipe” conceptThe researchers derived the concept from organ pipes: “Organ pipes also need a hole togenerate vibration and produce a sound”, ex-plained Hufenus. Thanks to this trick, it isnow possible to produce the required irregu-lar cavities in Gottardo’s laboratory model.However, this doesn’t make the project anysimpler. The geometric shapes that are cre-ated are more than complex, and the turbu-lence can cause the filament to break.

Holes seem to be the way to go, also inreal spinning nozzles with hot, melted plastic.Instead of a single hole in the nozzle, Gottar-do experimented with several holes of differ-ent sizes. She observed, for instance, thatsmall holes create a continuous flow of thecore fluid, whereas larger holes have a ten-dency to cause droplet formation. If a nozzlehas a small hole in the centre and bigger holesaround it, the droplets from the large holes“interfere” with the continuous flow of liquidfrom the small hole. This creates instability inthe flow, which can be used to structure thecavities.

But since the laboratory model cannot betransferred one-to-one to the extruder, the re-searchers will first have to simulate theprocesses in the extruder. Hufenus: “We will


Operation Cleanup In Empa’s “Combustion Engines” laboratory, a team is working onthe diesel exhaust cleaning system of the future. This is becausediesel engines will still be with us for decades to come – in heavytrucks, construction machinery, commercial vehicles and the like.To clean diesel exhaust more efficiently, the researchers aredeveloping nothing less than underhood “chemical mini plants”.

TEXT: Rainer Klose / PICTURE: Empa

The pipe that will be used in a few months’ time to demon-strate whether and how diesel exhaust can be cleanedmore efficiently is still cold. However, the electric heater

has already completed its trial run up to 500 degrees C. The op-tical measuring devices, the high-speed camera and the pulsedlaser are at the ready. Measuring can begin.

Switzerland’s only exhaust laboratory is going to help tocomply with diesel exhaust limits, which are going to becomemore stringent over the next few years. The results will main-ly be useful to medium-sized vehicle manufacturers in themunicipal vehicle area or the construction machinery indus-try, for example. But the majority of people who read this article and breathe in air at the side of a road or next to a con-struction site in 15 to 20 years from now will also reap thebenefits. As little soot, nitrogen oxide and acrid-smelling am-monia as possible should be released into the environmentwhen trucks (which will continue to use diesel engines in thefuture) are shooting past or construction machinery is oper-ating. Besides, the machinery should also consume as littlefuel as possible.

This requires quite a number of chemical tricks. The“small chemical plant” that filters and detoxicates the exhaustin modern trucks will have to become even more complex inthe years to come. What’s more, complex exhaust treatmentsystems that today are only found in heavy trucks are goingto be installed in tractors and construction machinery at a lat-er date as well. Thus, solutions that are both technically effi-cient and cost-effective are required if a manufacturer wishesto compete on the global market. And Empa helps to deliver.

Diesel exhaust contains a mixed bag of nitrogen oxides,collectively called NOx. These are unavoidable in combustionprocesses at high temperatures. Conventional catalytic con-verters such as the ones used in petrol engines cannot reduceNOx, which are responsible for the formation of smog, irritatethe respiratory tract and form nitric acid in combination withwater.

The nitrous oxides are removed by means of reduction.Small diesel engines in passenger cars use a NOx storage catalytic converter, which collects the NOx and has to be“emptied” every now and so often. To do this, the engineruns “rich” for about ten seconds every two minutes. Morediesel fuel is injected, and the non-combusted carbon in thefuel reduces the NOx into harmless nitrogen and watervapour. Advantage: cleaner exhaust. Disadvantage: higherfuel consumption.

Adblue cuts consumptionHowever, additional fuel consumption in their vehicles is athorn in the side of haulier companies. They are placing theirbets on a different solution: urea injection. Urea dissolved inwater, which is marketed under the trade name of “Adblue” inEurope and the USA, is injected into the hot exhaust. The ureabreaks down into CO2 and ammonia – and this in turn can re-duce NOx. Advantage: no increase in fuel consumption.

However, even this solution has a drawback: if you injecttoo little Adblue into the exhaust, only part of the nitrogen ox-ides is destroyed. If too much Adblue is injected, ammonia re-mains – which is less than desirable due to its pungent smell

The heart of the exhaust laboratory isthe glass test chamber, illuminatedwith red and green laser light.


and toxicity. The latest exhaust gas cleaning systems thereforeoperate on the “safe side”: only about 60 per cent of the requiredquantity of Adblue is injected to avoid stench at all costs.

This is where the Empa exhaust gas laboratory comes in– a ten-meter installation on the second floor of the Empa en-gine building. The intention is to perform several series oftests in order to investigate how the Adblue solution can bemixed with the exhaust as efficiently as possible, how muchAdblue one would have to add (depending on the engine op-erating load) and how emissions can be optimised with theleast technical effort.

Experiments with “simulated” exhaustThe researchers in the Empa “Combustion Engines” laboratorywant to tackle the problem in individual stages. Firstly theywill examine different injection nozzles. The nozzles will besuspended in a glass chamber, which will be flushed withcompressed air at up to 500 degrees C. A high-speed camerawill then record how the injected additive is distributed in this“simulated” exhaust. Even the speed and path of individualdroplets can be documented at 10,000 pictures per second.The analytic methods that will be used are known as shadow-graphy, Schlieren imaging, PIV (Particle Image Velocimetry)and PDA (Phase Doppler Anemometry).

In the first six to nine months, project leader DimopoulosEggenschwiler and his Ph.D. student Alexander Spiteri primar-ily want to concern themselves with spray and fluid dynam-ics. Their goal is to work out a scientific system that will allowsmall and medium-sized vehicle and construction machinery

manufacturers to design an exhaust cleaning system “from arecipe book”, as it were, that best suits their own engines andrequirements. This is the only way to comply with future ex-haust gas limits.

In the second phase the researchers will determine the lo-cation in the exhaust system, at which an Adblue injection ismost effective. Besides the order of the cleaning stages, thesize of both the hydrolysis catalytic converter (in which Ad-blue breaks down into ammonia) and the SCR catalytic con-verter (in which the ammonia reacts with the nitrous oxide)are crucial parameters to be investigated. And finally theEmpa researchers are still looking for the best possible pre-cious metal to put into the catalytic converter.

In the final stage of the project, various “diesel catalyticconverter” configurations will be tested in more detail.Whereas initial tests are run with hot air or artificially gener-ated gas mixtures, a commercially available diesel engine willnow be used to ensure the “prototypes” are tested under real-world conditions. A Swiss construction machinery manufac-turer has already teamed up with Empa, and hopes to benefitfrom the experience.

Nobody needs to worry, though, about thick clouds of ex-haust coming out of the Empa engine building. The tests areonly run for a few hours. At most, the total exhaust correspondsto that of one additional truck on the Überlandstrasse – a four-lane motorway running past the Empa campus in Dübendorf.However, the knowhow to be gained will help us all to reducethe exhaust burden in the years to come. //


Video:Engine labfor ecologicaldrivetrains

New insights fromold samplesAlfred Werner, who later won the Nobel Prize, created thebasis for modern complex chemistry in 1893 – without asingle experiment. But proving his theory turned out to belaborious and time-consuming – apparently becauseWerner overlooked an important aspect of crystallisation.X-ray analyses carried out by researchers from Empa andthe University of Zurich on salt crystals producedby Werner’s team have now refuted this school of thought.

TEXT: Nina Baiker / PICTURES: Empa

For Empa chemist Karl-Heinz Ernst, itis (almost) all about stereochemistry,i.e. the three-dimensional structure of

molecules. “The spatial arrangement ofatoms in molecules is decisive for the chem-ical, physical and biochemical characteris-tics of a compound”, he explains. For ex-ample, the structure of proteins influencestheir functionality in the organism, as isthe case with enzymes. Ernst is mainly in-terested in a particular aspect of the spa-tial structure, the chirality or handed-ness. If two molecules that are otherwiseidentical behave like mirror images (likeour hands), the compound is known aschiral.

Chirality as the focal point ofscience and the world market

Many pharmaceuticals, fragrances, pesti-cides and fine chemicals are chiral – and areresearched intensively. Global sales of chiraldrugs of about 40 billion US dollars in themid-1990s have now more than quintupled.

1Laboratory notes from Nobel Prizewinner Alfred Werner.

2Metal complex salts more than100 years old.

3 The crystals that Werner and hisco-workers grew did not provideproof of chirality (handedness):Left-handed and right-handed formsare both contained in one crystal.


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>>

In order to manufacture chiral compoundson an industrial basis, catalytic proceduresare used that selectively only produce oneenantiomer, i.e. one mirror image form ofthe molecule, but not its “twin sibling”.

New research results and develop-ments in the area of stereochemistry arepresented annually at the “InternationalSymposium on Chirality”. Several yearsago, as a participant, Ernst put a questionto his colleagues that he considered to bequite simple – and did not receive an an-swer: “How did Alfred Werner actuallyprove his theory on the spatial structure ofinorganic complex compounds?” Ernsttherefore decided to reconstruct the historyof the proof and stumbled upon an amaz-ing discovery.

Alfred Werner (1866 –1919) is con-sidered the founder of modern complexchemistry. In 1893, he was the first to for-mulate a well thought-out coordinationtheory (which was contrary to the schoolof thought at the time), which still forms

the basis of complex chemistry today. Untilthen, metal complexes were drawn on paperas aliphatic compounds. Werner wrote offcolleagues who acted this way as “Stich-chemiker” (graphic chemists). He, on theother hand, arranged chemical groups spa-tially around a central metal atom and wasthus able to predict new compounds. Thisspatial arrangement also hinted at the possi-bility that metal complexes might be chiral.However, it took him another 18 years be-fore he was able to prove his theory. He wasawarded the Nobel Prize for chemistry forhis proof in 1913.

Alfred Werner’s “ingenious impertinence”The chemists of the 19th century who wereinterested in metal salts were fascinated bytheir wealth of colours. Educated in organ-ic structural chemistry, in 1893 Wernerturned the prevailing idea of the structureof these compounds on its head in his work“Beiträge zur Konstitution anorganischerVerbindungen”. Werner’s “knowledge” was

3

completely based on theoretical consider-ations; he had not carried out a single ex-periment. Similarly to August Kekulé withbenzene, the solution “appeared” to Wern-er in a dream, which he then wrote downin the middle of the night. An “ingeniousimpertinence”, as was appropriately for-mulated by a colleague at the time.

In the following years, Werner synthe-sised a large number of the metal complex-es that he had postulated. These resultsspoke in favour of his theory but did notprove it. This did not occur until 1911,when Werner’s Ph.D. student Victor Kingsucceeded in separating the left and rightmirror image forms after more than 2000failed attempts – therefore experimentallyproving the handedness of a chiral metalcomplex. As the method of proof he usedpolarimetry, i.e. the rotation of light’splane of polarisation. His colleagues there-fore frequently greeted him in the pubs ofZurich with: “Is it rotating yet?”

According to the current school ofthought, Werner could have proved histheory much sooner if he had just exam-ined individual crystals of another Ph.D.student of his, Edith Humphrey, sincethese were said to have split up by them-selves into left and right handed crystals.Even though it was more of an exception,it was already known that some chiral com-pounds split up “on their own” during crys-tallisation, and individual crystals only con-tained right or left handed molecules. Stereo-chemistry had already been launched byLouis Pasteur 50 years earlier by separatingtartaric acid into the two enantiomer formsusing this method.

Humphrey had been dealing with chiralmetal complexes since 1898. Even so, sheand Werner obviously never examined thecrystals closely enough for their handed-

ness. Werner himself, though, had takenthe possible self-splitting of chiral com-pounds into consideration back in 1899,and discussed it in a publication. The “vic-tim” of the long drawn-out verification pro-cedure was Werner himself; the analyticalchemist was nominated for the Nobel Priceevery single year from 1907 on. However,it was not until he was able to experimen-tally verify the chirality of various com-plexes that the theory was generally ac-cepted, and he finally was awarded the Nobel Prize for chemistry six years later.

New insights from old samplesIn a paper recently published in “AppliedChemistry”, Karl-Heinz Ernst now came tothe conclusion that Werner could not haveproved his theory without further ado on thebasis of Humphrey’s samples. For two years,Ernst had immersed himself in the work ofWerner and his colleagues in his spare time.With colleagues from the University ofZurich Ernst even carried out X-ray structuralanalyses on original samples more than 100years old – and made some completely newdiscoveries about the structure of the crystalsthat Werner’s team had produced.

The analysis of Ellen Humphrey’s crys-tals revealed that they had not separatedthemselves into left and right handedforms. Only very few (and extremely tiny)crystals had accumulated one mirror imageform over the other. In other words: IfHumphrey had examined large crystals forchirality, the result would have been nega-tive. Ernst proved that the crystals are so-called twins, containing left and righthanded forms, with a sandwich structure.The school of thought with regard to theself-splitting of chiral compounds will thushave to be revised, at least as far asHumphrey’s samples are concerned. //

1Nobel Prize winner AlfredWerner: like Kekulé, thesolution to the problemappeared to him in a dream.

2Ph.D. student Victor Kingseparated the left andright hand enantiomers in1911. This cleared the wayto Werner’s Nobel Prize.


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It is regarded as the most successful internationalenvironmental agreement and has been ratified by196 countries – the Montreal Protocol on Sub-

stances That Deplete the Ozone Layer. As a result,CFCs and ozone “killers” will gradually disappear fromthe atmosphere over the coming decades. And becausemany of these substances are also very active green-house gases, the Earth’s climate will profit too.

So far, so good. In many processes where previouslyCFCs were used, these are now being substituted by fluor-inated compounds such as HFCs (which, simply put, aresimilar substances to CFCs but do not contain chlorineand do not deplete stratospheric ozone). They are usedas cooling agents in air conditioning plants and refriger-ators, as propellants in aerosol cans, as solvents and asfoaming agents in the manufacture of foam products.However, there is a downside to the use of HFCs – theyare also very potent greenhouse gases. HFC-134a, alsoknown as R-134a, for example, which is used in automo-bile air conditioning units, is 1,430 more active than the“classic” greenhouse gas carbon dioxide (CO2).

Equivalent of ten billion tonnes of CO2The significant increase in global emissions of HFCsseen over the past few years will soon negate the pos-itive effects on climate brought by the Montreal proto-col’s CFC phase-out.

This link is shown by an analysis published in bythe magazine “Science” in its February issue. An inter-national team of researchers, headed by Holland’s

Guus Velders and including Empa researcher StefanReimann, investigated the unintentional (positive) cli-mate effects resulting from the Montreal Protocol: theCFC ban has prevented the equivalent of ten billiontonnes of CO2 being emitted into the atmosphere in2010, five times the annual reduction target set by theKyoto Protocol.

Velders, Reimann and their co-authors fear thatthis positive effect will soon be negated by HFC emis-sions, which are currently increasing at 10 to 15 percent annually. In their article they state that “the HFCcontribution to climate change can be viewed as an un-intended negative side effect” of the Montreal Protocol.The greatest problem, according to the scientists, ispresented by saturated HFCs, which are extremely sta-ble and survive in the atmosphere for up to 50 years, ex-hibiting a long-term global warming potential of up to4,000 times higher than CO2. For Empa researcherReimann the situation is clear: “Long-lived HFCs shouldno longer be used in these quantities.”

A “simple” solution: expanding the scopeof the Montreal ProtocolAmong other things, the scientists recommend modify-ing the Montreal protocol so that it also covers the useof long-lived HFCs. “Since it is it is as a result of theMontreal protocol that these substances are being man-ufactured in increasing amounts, they could be includ-ed in the agreement too, so their use can be regulatedas well”, maintains Reimann. //

The Montreal Protocol led to a global phase-out of substances thatdeplete the ozone layer, such as chlorofluorocarbons (CFCs). Buttheir substitutes, Hydrofluorocarbons (HFCs), are climatically veryactive and many are also extremely long-lived. In the renownedjournal “Science” an international team of researchers recommendsthat the most potent of these gases also be regulated.

TEXT: Michael Hagmann / PICTURE, ILLUSTRATION: Empa

Cooling agentsheat up climate

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Knowledge and technology transfer // 11

12 // Knowledge and technology transfer

The new seat has a moving backrest consisting of rib and joint elements that simulate the structure of ahuman torso. Researchers from the Institute for Energy and Mobility (IEM) at the University of Bernedeveloped the drive concept and control console, which allows the ergotherapist to program the backrest

movements so that the sitting posture of the wheelchair user is altered in an optimal fashion. Depending on the“model”, the backrest can be tilted up to 22 degrees forwards and 40 degrees backwards, it can be rotated hor-izontally by a good 30 degrees in each direction and therefore “forces” the person in the wheelchair to changetheir sitting position and relocate the pressure points, as measurements with a pressure mat on the seat haveshown. “If someone happens to feel uncomfortable, the presettings can be modified individually at any time”,explains Empa project leader Bernhard Weisse. Extremely practical: the 24-volt battery that supplies the wheel-chair with energy also moves the backrest.

Empa wouldn’t be Empa if it hadn’t given the new development a comprehensive practical test. Test usersof different weights drove the prototype over pebble paths, up and down ramps, over kerbstones and cobbledroads. A winding road trip with the Tixi-Taxi, the transport service for handicapped persons, served to evaluatethe load on the backrest – all to the complete satisfaction of Hochstrasser and Weisse.

Clinical studies will be commencing soon. These will show whether the pressure values measured in thelaboratory actually do improve the well-being and health of handicapped persons, and whether they accept theinnovation. //

Wheelchair ergonomicsPeople who depend on a wheelchair usually have problems becausethey are always sitting in the same position. This can lead to pain,deformities and sores (decubitus). Engineer and ergotherapist RogerHochstrasser, founder of r going, wanted to help. Together withEmpa researchers, he developed new seats for improving wheelchairergonomics and therefore avoiding additional therapy costs. Theproject was funded by CTI, the Swiss innovation promotion agency.

TEXT Martina Peter / PICTURES: Empa

1The moving, program-mable backrest, withwhich an ergo-therapist can changewheelchair posture.

2Test drive with aprototype of the newwheelchair.

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Knowledge and technology transfer // 13

Healthy people move an average oftwo to four times per hour in theirsleep. The movements are trig-

gered by pain that occurs when tissue hasan insufficient blood supply. The sleepingperson changes position involuntarily, re-lieves the pressure point and therefore pre-vents bedsores, which are known in pro-fessional jargon as “decubitus ulcers”.

However, the decubitus prophylaxisthat is “built in” by nature does not workin people with paralysis and patients whoare sedated, unconscious or suffering froma high fever. The lack of movement means

that parts of the body remain under pres-sure for too long, and the microcirculationis interrupted. If this persists for too long,it can result in a painful bedsore.

In order to prevent this, bedridden pa-tients must be moved at regular intervals.Compliant Concept, a spin-off of Empa andETH Zurich, has developed a “MobilityMonitor” that alerts nursing staff when it istime to reposition a patient. The system as-sesses and records the mobility of a bedrid-den person. “The monitoring system is partof our concept for decubitus prophylaxis”,says Michael Sauter, the founder of thecompany, who collaborated with doctorsand care experts to develop the system. Hisgoal is an entire hospital bed system thatimitates the movements of a healthy per-son during sleep and therefore continuous-ly and gently moves the patients.

The measuring unit of the new systemis installed beneath the mattress and con-nected to the display unit at the edge of thebed as well as to the light-signaling system.The monitor uses a traffic light system toshow how mobile the patient is at any giventime, and therefore provides valuable in-formation that helps nursing staff to cor-rectly estimate the risk of decubitus, andtherefore reduces unnecessary physical ef-fort. The system also reminds the person-nel when the next movement is due and is-sues a warning if too much time has goneby since the last movement.

Successful in numerous tests“The nursing staff are often unsure whetherthe patients need to be moved at all. Theycannot stand at the bedside all the time toobserve movements”, emphasizes Sauter.“Particularly during the night, it would bebetter if the patients’ sleep did not have tobe disturbed unnecessarily”. In the last fewmonths the new system has proved itself tobe extremely useful in numerous tests incare homes and hospitals. The “MobilityMonitor” will be available on the Swiss mar-ket as of May. Until then it can be purchaseddirectly from Compliant Concept.

Financing for further projects relatingto the “intelligent” hospital bed, for whichthe fledgling company has already receivedseveral awards, has been secured until theend of the year. Until then Sauter wants toobtain additional capital for the companyby means of another round of financing sothat the product can be launched inter-nationally over the next few years. //

More at: www.compliant-concept.ch

The motion sensor is suspended from theedge of the bed and records whetherthe patient has changed position duringthe night. The measurements can also beanalysed on the computer.

While you weresleepingIn May a monitoring system is becoming commerciallyavailable that will allow nursing staff to accurately recordthe mobility of bedridden persons. The system has beendeveloped for the prevention of bedsores by CompliantConcept, a start-up at Empa’s glaTec technology center.

TEXT Martina Peter / PICTURE: Empa

MODULE 4

Components made of woodNew adhesives and manufacturingmethods for laminated wood andplywood are intended to make woodcomponents better and more popular.Novel protective coatings and naturalprotective layers improve the material’s

durability. (Empa, ETH Zurich,University of Berne,Université de Fribourg)

MODULE 6

Recycling, reuse and disposalWhat’s the best way of recycling woodbiologically? Which environmentalproblems does society have to keep inmind as the use of wood increases?(ETH Zurich, EPF Lausanne).

MODULE 5

Wood in a “supporting” role Can beech be used as a building material?How can multi-storey wooden housesbe soundproofed to prevent footfallnoise? How resistant to earthquakesare they? Can wooden houses beassembled by robots? (Empa,ETH Zurich, University ofWest Switzerland)

14 // Focus: Wood research

Wood – sustainable resourcewith a bright future

The National Research Program“Resource Wood” (NRP 66)

Ten million cubic metres of wood grow in Switzerlandevery year, but only two thirds of it are utilised.The Swiss forest is expanding and getting older.

The National Research Program 66 is intendedto increase the demand for domestic wood and

develop innovative ways of adding economic value.There is a surplus of Swiss wood – and it can be

a substitute for crude oil.

NRP 66 was instigated by the Swissgovernment in 2010. Research projects

started in January 2012.

MODULE 1

The source material:raw timber

Where and when can wood best beharvested in Switzerland?

(Swiss Federal Institute for Forest,Snow and LandscapeResearch, WSL)

MODULE 2

A commodity for thechemical industry

Lignin, a major wood constituent, canbe the starting point for many

chemical substances. Waste wood couldalso be used for this purpose.(EPF Lausanne, ETH Zurich, PSI,

various universities ofapplied sciences)

MODULE 3

A renewable energy sourceWood furnaces? That was yesterday’sthing. Research is now focussingon purified wood gas, bio-methane

and high-purity hydrogen produced fromwood. (PSI, ETH Zurich, LucerneUniversity of Applied Sciences

and Arts)

Focus: Wood research // 15


Video:Wood researchat Empa

Boulevard ofbroken beamsHow can professional repairs be made tocracks in support beams? Is it better touse screws or carbon fibre mats? And:how much strain can the fixed componentstill withstand? Empa engineers seek andfind answers.

TEXT: Rainer Klose / PICTURE: Empa

With all due respect, project leader Robert Widmannfrom the “Structural Engineering” laboratory and Roman Frei, student at the Berne University of Applied

Sciences, keep their distance to the hydraulic press in Empa’s en-gineering and construction hall. A beam made from glued lamin-ated wood, consisting of 13 layers of spruce and two layers of ash,is being “tortured” to death. The beam bends silently, accompan-ied by the humming of the hydraulic pump. Then, at a load of430,000 newtons, corresponding to a weight of 43 tonnes, thecomponent breaks with a muffled, dry crack.

Instantly Roman Frei reaches for the crank handle of the hy-draulic press and reduces the oil pressure. Both scientists spottedthe millimeter-thin crack that occurred from afar. Now they movecloser to the broken beam and examine what has happened.

The “tortured” beam is part of a series of tests within a re-search project funded by the Federal Office for the Environment(FOEN) for a “practice-oriented survey and reinforcement of com-ponents made from glued laminated wood”. In other words: theidea is to compare different reinforcement methods that can beused on cracked support beams. You can screw the crack together,


A technician reinforces thebroken wooden supportwith carbon fibre mats andepoxy resin. The sampleis left to dry for one week,then its load-bearingcapacity is tested in thehydraulic press.

>>


glue it or stick a “plaster” made of carbon fibre around the dam-aged component. This method is frequently used on damaged con-crete supports. But would it also work with wood?

The sorry test beam was prepared meticulously for its datewith destiny: the Empa researchers deliberately introduced a ma-terial fault when they glued the individual boards together. Gluewas only applied to one-third of the contact surface of the middlelayers. The intention was for the beam to break at this soft spotand then be repaired in order to prove the effectiveness of the re-pair method in subsequent tests. All in all, there would be eightof these tests, evaluating four different repair methods: one, twoor four fully-threaded screws per breaking point and carbon fibremats glued around it with epoxy resin.

The result even surprised the experts: with just a single screwper breaking point, the glued laminated wood beams withstood ahigher load than in the non-reinforced condition. The repairmethod using carbon fibre mats was similarly effective. On theother hand, it is unnecessary to repair the beam with more thanone screw per breaking point – this only makes the beam breakin other locations, i.e. extra screws do not provide additional re-inforcement. In order to document the experiments the brokenbeam will then be X-rayed. Many beams are even cut open andassessed on the basis of the individual components. Wood con-struction companies all over the country will benefit from thisnew knowledge, and will be able to make repairs to support struc-tures more efficiently in future. //

>>

Now it gets serious: project manager Robert Widmann (left) monitors the three-pointbending test on the carbon-reinforced wooden support. Engineering student RomanFrei (far right) operates the hydraulic press. At a load of 43 tonnes thelaminated wood support breaks with a dull crack, and the displacement is measured.One can monitor where and when the break occurred on the computer screen.


“Wood has manyadvantages.”

>>

Mr Burgert, what qualifications do you need to becomeProfessor of Wood-based Materials?

Ingo Burgert: you can start with studying wood science and thendo a doctorate. In my case this was at the University of Hamburg.

What was the topic of your doctorate?I wrote a thesis on the mechanism of wood rays in trees. These

are the structures that run radially along the cross-section of thewood and therefore look like the spokes of a wheel. I examinedthe mechanical properties of the wood rays and how they con-tribute to maintaining the stability of the tree.

Wood is a material that has been used and studied for along time. Isn’t it difficult to obtain new knowledge aboutthis well-known material?

Wood is a biological material and therefore has a hierarchicalstructure. This means that the nanostructures and microstructuresof wood are decisive for its macroscopic characteristics. The im-

Ingo Burgert was appointed Pro-fessor of Wood-based Materialsat the ETH Zurich in October oflast year; the 43-year-old alsomanages the research group for“Bio-inspired Wood Materials”at Empa. In a conversation withEmpaNews he explains the goalshe is pursuing.

Interview: Rainer Klose / PICTURE: Empa


I look at nature and think about what I can learn from it. Thismay or may not be simply copying. On the contrary, we must understand the principles in order to utilise them to modify themicrostructure and the chemistry of the cell walls. I will thereforegear up my team with suitable specialists such as polymerchemists. My working groups have always been extremely inter-disciplinary. For our work you need expertise in wood science, biology, chemistry, physics and material sciences. You also needmethodical ability in order to analyse the nanostructure and themechanisms at a cellular level. We would like to carry out basicresearch to broaden our understanding of general principles, andat the same time develop novel wood products by making use ofthe acquired knowledge and ideas.

Speaking of methods: how will you examine thenanostructure of wood?

Besides electron microscopy we use spectroscopy, scatteredX-ray methods and nanochemical and micromechanical character-isation. When doing this it is important to examine the cell wallas an intact unit in spite of its complexity. When I examine iso-lated cell wall components that have been removed from thewhole, I lose important structural information and therefore ac-cess to the structure and mechanics of the whole.

portant element that controls the characteristics in large structurescan be found in the small, the cell wall structure. We are now ina better position to examine the nanostructure and the microstruc-ture in much greater detail, and even characterise it mechanically.In this way, we can obtain new knowledge of the basic mech-anisms and structural parameters that determine the properties ofwood.

Where is your research going to take you?What do you want to do?

Wood has many advantages. Considering its low density, ithas extremely good mechanical properties. However, it also hastypical disadvantages such as its combustibility and the problemof expansion and contraction. We want to go down differentroutes with our research in order to minimise expansion and con-traction, and thus make wood more “dimensionally stable”. An-other topic is durability. Wood from some types of tree is durable,wood from other types much less so. We want to discover howgreater durability can be “built into” the wood. Thenano- and microstructure play a major part in all ofthese questions, since the characteristics of the woodcell walls determine the behaviour of the material.

Are you saying that wood does not just have to beexamined superficially, but that you have to godeep into the structure?

Correct. The question is: in addition to existingmethods, what ways are there of efficiently modifyingthe cell wall so that it binds less water? Because this isultimately responsible for the expansion and contractionof wood.

Which types of wood do you start doing researchwith? Or doesn’t this matter at all?

Now we are talking about the designation of myworking group, “Bio-inspired Wood Materials”. We canlearn a great deal from nature about these matters: manytypes of tree such as oak or robinia form real heartwood,which can make the wood significantly more durable.Heartwood formation takes place after the fibres of the wood havelong since died off, and are fulfilling their strengthening functionin the tree. It is, therefore, possible for the tree to make belatedchemical modifications to its wood. Of course, the tree is not try-ing to make the wood more usable for our construction projects –on the contrary, heartwood in the tree is used for depositing meta-bolic products. But we can learn from the underlying mechanisms.

If we now want to bring about this process artificially, wewould have to three-dimensionally penetrate the woodstructure – i.e. make use of the supply lines of the tree. Howis that possible?

Making use of the supply lines of the tree is problematic, sincethese are only functional to a limited extent after the tree has beenfelled. We will therefore not be in a position to deal with wood elem-ents with large cross-sections. However, we can modify woodwith a small diameter and then create bigger elements by gluingthese parts together. The latter is a normal procedure during woodproduction.

If I understand you correctly, are you saying that you are akind of microstructural engineer for wood looking for theadequate chemistry to replicate such structures?

Biography Info

Ingo Burgert (43) is Professor for Wood-based Ma-terials at the “Institute for Construction Materials”at the ETH Zurich and group leader in Empa’s “Applied Wood Research” laboratory since 2011.He studied wood sciences at the University of Ham-burg where he gained his Ph.D. in 2000. He thenworked at the University of Natural Resources andLife Sciences (BOKU) in Vienna. Before joining EmpaBurgert managed the Plant Biomechanics and Bio-mimetics group at the Max Planck Institute of Colloids and Interfaces in Potsdam.


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How will you organise your team between ETH and Empa?A few employees over there, a few over here?

I would like to separate the activities as little as possible.There should be one team with two locations, not two separategroups, because I would lose some of the synergy I can achievewith the combination of Empa and ETH. My employees shouldtherefore be flexible and not set themselves up at a desk in one orthe other location, but move between Empa and ETH with a laptopat hand. After all, research lives from com-municating and exchanging ideas andknowledge. I consider the fact that we canexperience this in our daily work both withcolleagues at Empa and with the researchgroups at ETH a unique opportunity.

How do you interact with the otherresearch groups of the “Applied WoodResearch” laboratory at Empa? There are many areas, in which we work to-gether and can provide mutual support foreach other. Here at Empa, the modification ofwood is the prime topic. Tanja Zimmermann,the leader of the laboratory, is one of the leading experts in the areaof nano-cellulose. There are a lot of synergies in the area of the nano-and microstructural characterisation of materials. Martin Arnoldworks on surface modification. He is very experienced in wood tech-

nology and will be an important partner when it comes to practicalapplications of our results. Francis Schwarze has a large amount ofexpertise in the area of wood decomposition by fungi, we will workclosely together on questions such as how to make wood more ac-cessible and easier to penetrate. He has fantastic opportunities to re-activate the original transport routes of trees. But there are also over-laps with groups in other labs, for instance with René Steiger in the“Structural Engineering” laboratory.

Now you’re really entering the realmof the macroscopic…Yes, with wood components and entirebuildings we’re actually closing the loop.Because eventually my work will also bemeasured against whether or not we are capable of transferring our nano- and mi-crostructural modifications of wood into themacroscopic world. Improved properties,which only manifest themselves on a few cu-bic millimetres of wood, are not very interest-ing with regard to wood utilisation. With ourresearch we want to lay the foundation for

innovative wood products and contribute to adding economic val-ue to this tremendously important natural resource. The prereq-uisites for this exciting task are ideal here at Empa and at the ETHZurich. //

“My employeesshould movebetween Empaand ETH witha laptop at hand.”


Wooden wonderfrom the potCan cellulose help to protect wooden surfaces fromweather impacts? Empa is looking into this. But itdoesn’t stop there; this “wonder material” may soonalso be used for spinal disc replacements, foodpackaging and filtering CO2 out of the atmosphere.

TEXT: Rainer Klose / PICTURES: Empa

1


The secret of this material’s successoriginates from a simple aluminiumfunnel containing cellulose soaked

in water. From here, hoses lead to a high-pressure pump. In a brute force approachof sorts, the pump pushes cellulose fibresthrough thin, branched capillaries at pres-sures of up to 1,500 bar – an obstaclecourse made of solid steel. The delicate ma-terial comes off second best; the result is“nanofibrillated cellulose”, in short NFC:tiny flakes of nanometre-thin fibres withamazing properties.

“We only need to stir one or two percent by weight of NFC into water, and wealready have a stable gel”, explains TanjaZimmermann, one of the leading NFC ex-perts in the world, who has been dealingwith this substance for about ten years. Shehas since tried out quite a few things withNFC. For example, the fibrils were used incollaboration with an industrial partner forreinforcing wood glue (polyvinyl acetate).Another project is investigating whether a

biopolymer NFC gel is a suitable substi-tute for the jelly-like core of the

spinal disc (“nucleus pulposus”).At Empa in St. Gallen, NFC-re-inforced fibres have alreadybeen spun, and start-up com-pany “Climeworks” extractsCO2 from ambient air in atechnically sophisticatedway using NFC foam. Infuture, it may be possibleto use the greenhouse gasto produce synthetic fuels.

Before too long, wemight also encounter thiswonder material in the

fridge – it is under discussionas a barrier material for food

packaging. “We mix the fibreswith clay particles, which works

quite well after a minor chemicalmodification”, explains Zimmermann.

Then the mixture is homogenised using ahigh-pressure procedure, compressed in afilter and hot-pressed. This produces a filmthat holds back water vapour and oxygen.“Our material could be used instead of alu-minium foil, which is found in a lot of foodpackaging”, hopes the Empa researcher. Abig advantage of the NFC/clay film: it canbe burned without problems and evencomposted, since the cellulose fibrils arebiodegradable.

Now the researchers have set theirsights on another potential application: im-proving coatings for wood protection. Cana substance that has been extracted fromwood or straw indeed help to protect the

surface of wood? Enter Martin Arnold, anexpert in matters concerning the resistanceand weathering of wood. Which con-stituents of the wood surface are attackedby the sun’s UV rays? What happens tothem? Is the decomposition product solublein water, and is it washed out by rain?Arnold knows the answer. In the cellar ofhis lab he has a “weathering machine”, inwhich wood samples are irradiated with UVlight and rained on time and time again –an endurance test for wood and protectivecoatings. The effect of light is easy to beseen on any old piece of wooden furniture:“Dark wood becomes lighter in the light,but light wood becomes darker”, explainsArnold.

Reinforced protective coatingA protective coating that is impervious tolight helps to prevent this – but usually thisalters the original colour of the wood.Arnold is familiar with the problem: “Themore transparent the coating, the faster theprotective effect abates. Nobody has solvedthis problem yet.” As if this weren’t enoughthere is yet another issue: the expansionand contraction of wood. Any coating thatis to last for a number of years must flexiblyadapt to the working wood. If the coatingbecomes brittle, it cracks – and the woodunderneath is then exposed to rain and mi-crobial attack.

The Empa researchers believe that NFCfibres can help with precisely these two is-sues as constituents of a protective coating.UV-absorbing substances, e.g. in the formof nanoparticles, could be embedded in thematrix of the cellulose fibres. And with thehelp of these fibre networks the substanceswould also be evenly distributed in thecoating. The crack resistance of the NFC fibres that has already been demonstratedcould also reinforce the coating and preventcracking. The coating would thus have abetter protection from hailstone impacts.

However, there are still many obstaclesto overcome. For example, cellulose –which is inherently “water-friendly” – mustbe chemically modified so that it also dis-perses itself in “oily” wood protection coat-ings. Initial tests have been carried outsince the beginning of the year within thescope of National Research Programme(NRP) 66 (see also pages 14 and 15). //

2

1Cellulose is prepared for high-pressure treatment in this metalfunnel. Tanja Zimmermannand Martin Arnold want to usethis “wonder material”for improved wood coating.

2Nano-fibrillated cellulose underthe electron microscope: Clayparticles are distributed in thefiligree cellulose network in thissample. The clay forms minute“leaves” in the structure.


The surface of a piece of wood is full of biochemical “connectors”.A team at Empa considers this a perfect opportunity to outfitwood with exactly the features we would like it to have: surfacesthat are easy to stick to, anti-fungal coatings – or even self-adhesivewood chips that can be compacted into fibre boards that are100 per cent ecological, without any chemical additives whatsoever.

TEXT: Rainer Klose / PICTURES: EmpaTEXT: Rainer Klose

1Mark Schubert compares asample of fungus-treated woodto a non-treated sample(right of picture). The fibrepanel (big picture) he isholding can be manufacturedwithout chemical adhesives –the wood is self-bonding.

2Enzyme treatment: the laccaseuses chemical “docking stations”on the surface of wood andthus makes the wood reactive.

Biologically refined

1


Sometimes innovations start with a simple run through thewoods: “One particularly good idea occurred to us when wewere out jogging”, explains wood expert Mark Schubert from

Empa’s “Applied Wood Materials” laboratory. Occasionally Schu-bert does a few laps in the woods with his colleague Julian Ihssen.The two of them set off one day, and Schubert had an unfinishedproject on his mind. This time they came back with a cracking idea:the vision of an antimicrobial wood surface.

But let’s not get ahead of ourselves: Schubert, who is a qualifiedforestry researcher and environmental scientist, initially studiedways of combating fungi that damage wood by other fungi. Then,for several years, he turned to using fungi to specifically modify theproperties of wood. Currently, Schubert is working on certain en-zymes from fungi that have specialised in “digesting” wood duringthe course of evolution. Laccase, for instance, which is produced bymany white rot fungi, can modify the surface characteristics ofwood: it converts some chemical sub-structures of lignin, a woodconstituent, into radicals – making the surface of the wood reactive(see picture).

Herbal fungicide of ancient EgyptBut what can you do with a wood surface that is then “open to newideas”, in a manner of speaking? Well, first, you could consider awood preservative that can be firmly anchored to the surface andwill give the bare wood better protection from decay. Schubert start-ed to run tests with isoeugenol, an antioxidant, and thymol, a herbalfungicide, which were already used by the ancient Egyptians to pre-serve their mummies. But his initial attempts fell on stony ground –the substances were too easy to wash off or lost their antimicrobialpunch in interaction with the enzyme.

Time to go for a jog, thought Schubert – which brings us backto the beginning of the story. Schubert told Ihssen, a researcher inthe “Biomaterials” laboratory, about his difficulties – and got astraightforward recommendation: “Try an old home remedy”. Thetwo of them gave it a go and actually succeeded with, of all things,a cheap substance that can be found in any medicine cabinet: thecompound literally stuck to the surface of the wood. By way of a trial,Schubert and Ihssen treated test pieces of spruce with aggressive,wood-damaging fungi. Whereas the untreated test pieces had beeneaten away deep into the wood after 12 weeks in the incubator, thetreated test pieces had withstood the fungi. What the remedy is can’tbe disclosed at this point, though – the researchers are consideringpatenting their discovery.

Laccase

Wood

OH OH

O2 H2O Further reactions

O? O?

The experiment proved two things: laccase functionalisedwood surface so profoundly that useful quantities of a desired sub-stance can be chemically attached to it. And applying a cheapmass-produced medicine to the wood provides antiseptic proper-ties that can be useful for many different applications. Just thinkabout wooden components and furniture in public buildings or onpublic transport, in hospitals, kindergartens and restaurants.

Now Schubert is hoping to find an industrial partner whowould be willing to develop this antimicrobial wood treatment toa stage where it can be marketed. He is also pursuing two otherprojects, for which the laccase modification has been the dooropener: if wood stuck to adhesives more effectively, strongerglued connections would result – even between wood such aslarch and beech, which have always been difficult to glue. In orderto do this, the wood is pre-treated with aqueous laccase solution.Functional groups such as amines could then be attached as an-chor molecules to the radicals that are produced. These anchormolecules can then chemically bind to the adhesive, making theconnection significantly stronger.

Anyone who would rather stay clear of chemistry may preferthe third application for enzymatically treated wood – adhesive-free fibre boards. If pre-treated wood fibres are compacted, theycan form chemical bonds with neighbouring wood fibres. Therewould thus be no need for chemical bonding agents such as resinsor isocyanates in the manufacture of so-called medium density fibre boards. A chemical-free, ecologically harmless fibre productcomes within reach.

Harmless to peopleThe use of laccases is nothing to worry about, explains Mark Schubert:the proteins are biologically degradable, they are harmless to peo-ple and animals and are also non-hazardous in case of skin con-tact. They perform their job on wood at room temperature – with-out using acids or alkalis beforehand. However, there is still agreat deal of detail work to be done before enzymes really take offin industrial wood treatment. Not all variants of the laccase enzyme are equally suitable for all types of wood, and in order tofind a suitable enzyme the enzymes must first be characterisedand compared. Cost-effective and efficient manufacture of laccasesfrom white rot fungi also has to be investigated further and opti-mised quite a bit. //

2

26 // Knowledge and technology transfer

Venture kick: start-up moneyfor artificial musclesCompliant Transducer Systems GmbH (CTSystems), the start-up company established byEmpa researcher Gabor Kovacs in August 2011, received 10,000 francs from the “venture kick”start-up foundation for its impressive business idea. Kovacs devotes himself to the mass pro-duction of artificial muscles, and his company is going to develop two production processes:a “stacker”, with which large quantities can be manufactured at low cost, and a “plotter”,which can manufacture extremely complex, fine structures for high-quality components (re-ported in issue 35 of EmpaNews in January 2012). For the first phase of the competition forstart-up grants, Kovacs submitted a short profile of his company and convinced the “venturekick” jury of his business idea in a ten-minute presentation. The money is now going to beused to develop a web site and cover the cost of cooperation negotiations.

The money from the “venture kick” funding initiative originates from funds from the AVINAfoundation, the Ernst Göhner foundation, foundation 1796, the Gebert Rüf foundation and theOPO foundation. Up to 130,000 francs per start-up project are distributed in several stages.Now that he has succeeded in obtaining the funds for the first level, Kovacs intends to applyfor the next stages in the coming months: 20,000 francs for a “business case”, in which cus-tomers-to-be and strategic partners have to be identified, and finally 100,000 francs for suc-cessful start-ups. At this stage the team has been put together, the intellectual property hasbeen protected and the company is ready for its market launch.

CTI: innovation programevery 9th project goes to Empa A flood of proposals for the Swiss government’s 100 million innovation programme to counter the strongSwiss franc hit CTI, the federal innovation promotion agency late last year. Up to the submission deadline on15 December 2011 a total of 1,064 applications to the value of more than 530 million francs came in; 105 pro-posals were submitted by Empa researchers.

Eventually 246 projects were approved. With 27 funded projects Empa had a success rate of about 26 percent. Grants to the value of 12.3 million francs will be winging their way to Empa’s Dübendorf, St. Gallen andThun sites. The projects range from hybrid drives for municipal vehicles to climbing skins for backcountryskiing, and from quantum cascade lasers to new concrete concepts for prefabricated parts.

In late September 2011 the Swiss government and parliament launched a special programme to counterthe effects of the strong franc in order to boost the competitiveness of the Swiss export industry. An additional100 million francs were made available to the CTI for promoting innovation. The goal was to allow companiesunder margin pressure to quickly implement innovative projects in collaboration with research institutes, firstand foremost projects with a rapid effect on the market or risky projects that companies have had to postponedue to dramatic margin erosion.

Science dialogue // 27

Events

16 – 20 April 2012 Intensive course: Nanopowders andNanocompositesEmpa, Dübendorf

26/27 April 2012 3-Länder-KorrosionstagEmpa, Dübendorf

2 May 2012 Imaging and image analysis of porous materialsEmpa, Dübendorf

23 – 25 May 2012 Fibre Society Conference 2012Empa, St. Gallen

11 June 2012 Electrical Overstress (EOS) – das «unbekannte» Phänomen inSchaltungstechnik und AusfallanalyseEmpa, Dübendorf

12/19/26 June 2012 Flottenmanagement ganzheitlich betrachtetEmpa, Dübendorf

13 June 2012 48th Discussion Forum Life Cycle Assessment:ecoinvent v3Empa, Dübendorf

30 August 2012Innovation Day 2012 (Textil und Bekleidung)Empa, Dübendorf

Details and additional events atwww.empa-akademie.ch

Your way to access Empa’s know-how:

[email protected] +41 58 765 44 44www.empa.ch/portal

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So sehen heute Wolkenkratzer aus.

Documents

EmpaNews April 2012