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Interesting facts about plastics and rubber

We come across plastics and rubber everywhere in our daily lives. Discover fascinating stories, surprising facts and interesting background information – from historical developments and well-known products to key figures and innovations in the industry.

Results (423)

  • Detection of plastic explosives etc. in letter bombs with terahertz radiation

    The attempted attack on Josef Ackermann is strong confirmation: letter and parcel bombs are a constant threat nowadays. The latest letter bomb found at Deutsche Bank and the explosion of a parcel in Rome make this very clear. It is evident that the systems commonly used are not effective enough to guarantee greater safety in postal deliveries. It is therefore essential that mail checking is improved – without having to sacrifice privacy. Metrology experts from Fraunhofer IPM are currently co-operating with Hübner GmbH, Kassel, and IANUS Simulation GmbH, Dortmund, to find a solution based on “terahertz letter scanners”. Terahertz letter scanners operate using terahertz waves, that are harmless to human beings. In contrast to X-ray letter scanners, they can therefore be used practically anywhere, such as in postal logistics, in prisons, at public authorities or at the homes of endangered private individuals. X-ray scanners of the kind that are familiar to some of us from airports require considerably more effort and expense, because – for example – protection has to be provided against the radiation emitted. Apart from this, X-ray scanners are not in a position to identify explosives – unlike terahertz waves, which make an analysis of the chemical content of the letters. The experts are convinced that widespread use of terahertz letter scanners in the postal logistics chain will enable endangered persons to be warned about letter or parcel bombs in good time. Suspicious mail can be checked on the spot and dangerous contents can be identified. Privacy is maintained as a result. Some background information. The terahertz range is a section of the electromagnetic spectrum that has not been used much up to now. It is located between microwaves and infrared light. For a long time, scientists talked about the terahertz gap, because there were no practical sources until the 1990s. Tremendous progress has, however, been made in recent years. The systems developed by Fraunhofer IPM are particularly compact, flexible and rugged. Terahertz waves penetrate paper, cardboard and plastic. Their special advantage: the molecules present have a definite chemical fingerprint in the terahertz range, so that it is possible not just to screen mail but also and above all to make a chemical analysis of the contents. It remains to be seen, however, when this kind of security technology will be introduced in letter and parcel distribution facilities. Irrespective of this: terahertz technology has a bright future thanks to its special properties. GD

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  • “Dream production” of PUR

    © BayerAG [dim_it:pic_desc]Bayer MaterialScience is testing the production of plastics with the help of carbon dioxide in a pilot plant in Leverkusen that came into operation in February 2011. A breakthrough in catalysis research made the innovative process possible. (Source: Bayer AG)[/dim_it:pic_desc]

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  • Plastic reduces the greenhouse effect

    CO2, which is known to be a pollutant that is bad for the climate, is now becoming a material of potentially high value: the chemical industry has had its eye on carbon dioxide as a possible source of carbon for quite a long time now, but separating the different elements has been considered difficult, energy-intensive and, as a result, uneconomic up to now. A new era is beginning now: research scientists from Bayer Technology Services have discovered catalysts that incorporate carbon dioxide in the molecular structure of plastics in an economically viable and environmentally sound way. Thanks to the “dream reaction” that has now become reality, use can be made of CO2 obtained from the emissions of brown coal power plants, e.g. for manufacturing polyurethane (PUR) in what is being called a “dream production” process. This is good for the atmosphere – helping to reduce not only the anthropogenic greenhouse effect but also and not least of all the consumption of crude oil, which is a finite resource. A pilot plant in Leverkusen operated by Bayer MaterialScience is supposed to develop the process so that it is ready to go to market by 2015. The participants in the project for which funding is being provided by the German Ministry of Education and Research include not just Bayer but also Aachen Technical University (RWTH) and RWE Power AG. Anthropogenic emissions of the greenhouse gas carbon dioxide attributable to energy generation climbed to a new record level in 2010. More than 33 billion tonnes (33 gigatonnes), almost six per cent more than in 2009, demonstrate that the international community has failed to take effective action against impending climate collapse. More than half of global CO2 emissions are attributable to China, the USA, India and Russia (see photo gallery:List of environmental polluters). If emissions are related to population, the emerging countries among the four biggest environmental polluters are not performing quite as badly as it might seem: considerably fewer tonnes of CO2 are still being emitted per capita in China and India than in most of the industrialised European states (see photo gallery: National per capita CO2 emission in selected countries), including Germany. Although we are considered to be good examples, because we have succeeded in cutting annual CO2 emissions by almost 30 per cent over the all-time national high, we are still in what is a not very flattering sixth place by volume in the current global table (see photo gallery: List of environmental polluters ). The CO2 performance at EU level is patchy too: although the European Union is likely to reach its climate target of undercutting the level of 1990 by 20 per cent by 2020 without any difficulty – with respect to other gases that are bad for the climate as well, incidentally – many feel that this is not ambitious enough in the meantime. The coalition government agreement concluded by the Conservative and Liberal Parties in Germany already talks about 40 per cent instead of only 20 per cent, for example. The Intergovernmental Panel on Climate Change (IPCC) set up by the industrialised countries recommends a CO2 reduction of this order by 2020 to limit global warming and even suggests that a reduction of at least 80 per cent is necessary by 2050. The international Climate Change Conference in Durban, South Africa, that just ended did not specify any such target at all, however, and critics think that there is a risk as a result that the average temperature on earth will be increasing by even more than the two degrees currently feared. So action to reduce CO2 emissions is needed more urgently than ever before. And any measures taken should neither be cancelled out by nor hamper ongoing economic growth. Up to now, it has seemed to be impossible to resolve this conflict – in the past, whenever CO2 emissions decreased significantly, this was due to economic recession. The conflict could, however, be resolved if a way could be found to make successful use of CO2, an industrial waste product, because of the carbon it contains – on the condition that this was done without having any adverse impact on the environment. So far, industrial use of CO2 has been restricted to such applications as carbonated drinks, dry ice in laboratory and food contexts, fire extinguishers that produce carbon dioxide snow (link: Brief portrait of CO2) or CO2 lasers. The chemical industry needs the gas to manufacture such carbonates as soda and potash too. Carbon dioxide is also involved when fog is produced artificially on nightclub dancefloors. While it creates better conditions for plants to grow in greenhouses (photosynthesis is the process promoted here – it is not unusual for natural gas to be burned specially for this purpose). It goes without saying that these applications are not climate-neutral – so that CO2 cannot get into the atmosphere, it would have to be processed in such a way that it is “frozen” in the final product, i.e. stays locked away for ever, as it were. An obvious solution would then even be to obtain the raw material from the exhaust gases of power plants or from the atmosphere itself. Trials carried out by the Bayer material research staff to take advantage of CO2 as a source of carbon and to incorporate the substance into the molecular structure of plastics have produced successful results in this context. Up to now, crude oil has provided the carbon needed; the fossil raw material could now be replaced by carbon dioxide, at least to some extent. Using CO2 in the production of polymers is not a new idea, but it has remained a theoretical possibility for decades because it poses tremendous technical challenges. Carbon dioxide molecules are very stable and are therefore slow to react, i.e. they are very reluctant to form compounds with other substances. The bond between one carbon atom and two oxygen atoms is so strong that it can only be separated by force, i.e. via activation energy, in order to make reactions with other chemical elements possible. Energy which has an immense quantum and the production of which releases new CO2 – a solution that cannot be viable. For this reason, research scientists for a long time considered the transformation of carbon dioxide into a raw material for the production of plastic to be a “dream reaction” – a reaction that probably only exists in the dream world. It almost turned into a nightmare for many research scientists, because their experiments failed again and again. Now the dream is becoming reality, however: after completing years of testing, chemists from the “Reaction Engineering & Catalysis” centre of excellence at Bayer Technology Services have found a catalyst that persuades stubborn carbon dioxide to combine with other substances. Catalysis, currently the most important interdisciplinary technology for the chemical industry, enables reactions that would never take place on their own to take place with only minimal activation energy. As long ago as the end of the 60s, Japanese research scientists had indicated the road that needed to be followed and had succeeded in demonstrating that CO2 can in principle be activated with the help of catalysts; the reaction speed was disappointing, however. In their attempts to optimise the process, Bayer research scientists achieved a breakthrough in 2008. The team headed by the chemist Aurel Wolf combined carbon dioxide and propylene oxide in about 200 test series using a different catalyst each time, with the subsequent application of heat. What is created in this context is polyether polycarbonate polyol (PPP), a viscous, colourless substance that acts as the basic material for the production of polyurethane (PUR). It is a substance of great use to chemists, because PUR – as is generally known – is a foam material of low weight that can be used universally to produce lightweight components – to an increasing extent in vehicle manufacturing as well – and that is particularly popular as an insulation material: polyurethanes that protect buildings against cold save about 70 times more energy than is consumed in their production. But to get back to our story: following application of the catalysts and completion of a specific reaction time, the Bayer research scientists determined how much PPP was produced in each case and how much CO2 had actually been incorporated in the polymer molecule. A maximum of 43 per cent by weight is possible without sacrificing quality. This is far more than the results achieved at the beginning of the tests. In 2009, the search for an improved catalyst was continued in the context of the “Dream Reactions” project with funding from the German Ministry of Education and Research and in co-operation with the Catalytic Centre at Aachen Technical University (RWTH), with the aim of getting the CO2 content of the PPP as close as possible to the above-mentioned level of 43 per cent. What has worked at the laboratory level is now to be confirmed in testing under industrial conditions so that the process can be launched on the market: “dream reactions” are being turned into “dream production”. Since February 2011, a pilot plant set up in Leverkusen has been producing sample batches of PPP that are supplied to Bayer MaterialScience, which processes them into polyurethane (the company manufactures 1.4 million tonnes of the plastic every year). RWE Power AG, Germany’s biggest power generator, is involved as the CO2 supplier. The environmental pollutant is extracted from the flue gas flow at the RWE brown coal power plant in Niederaußem in the first CO2 scrubbing system installed in Germany. The CO2 is then cleaned, liquefied and filled in containers for delivery. The process is to be fine-tuned in Leverkusen for at least four more years, not least of all in order to develop the optimum formulations: polyurethanes need to be versatile; soft foam is required for mattresses sometimes, while rigid insulation material for construction applications is needed in other cases. “We intend to be in a position to produce the ingredients for CO2-based polyurethanes from 2015 onwards. And they will then contain 10 to 40 per cent carbon dioxide”, says Project Manager Dr Christoph Gürtler, a chemist at Bayer MaterialScience. Another plan is to integrate carbon dioxide in other plastics, e.g. polycarbonates, as well in future - and possibly even in medical drugs that Bayer also manufactures. Whether and when the new process is ready to be marketed will be determined not least of all by its environmental efficiency; RWTH Aachen has been commissioned to complete the necessary analyses about this. Among the points that need to be settled is whether less overall energy is needed than in the past to produce PPP by using CO2. Dr Gürtler emphasises that the process is not at any rate a universal solution to the climate change problem and that this is not what Bayer was aiming to achieve anyway. At the present time, only 0.3 per cent of carbon dioxide emissions in Germany is made use of for industrial purposes. Experts estimate that this figure could be ten per cent by the end of the decade, if the potential for using CO2 to store excess power is included – something that is becoming increasingly important with the increase in renewable energy sources. So 90 per cent would still be unused even then – there is simply too much of the greenhouse gas around. All the same: Bayer and RWE have estimated that CO2 emissions could be reduced by five to ten million tonnes every year in future by using carbon dioxide in plastics production. Not much compared with the 33 billion tonnes that are released into the atmosphere around the world, but a step in the right direction – particularly in view of the fact that dependence on crude oil will be decreased quite considerably into the bargain: “About a third of the oil needed can be eliminated by using carbon dioxide”, explains Dr Gürtler. At the present time, more than half a billion litres of crude oil are processed into plastics around the world – every day! So it is no surprise that the “Dream Production” co-operation between Bayer AG, RWTH Aachen and RWE Power AG was one of the three finalists in the category “Germany’s most sustainable projects in 2011” when the German Sustainability Awards were presented in Düsseldorf in early November. The jury was impressed by the commitment to “energy-efficient, resource-minimising and environmentally sound use of CO2” and concluded that there were “excellent chances of success”. Copyright: Redaktionsbüro Guido Deußing Presse Text Kommunikation Uhlandstraße 16 41464 Neuss E-Mail: guido.deussing@pressetextkom.de

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  • Brief portrait of CO2

    • Colour- and odourless gas, heavier than air; natural content in the atmosphere: 0.03 – 0.04 per cent; forms carbonic acid when dissolved in water (about 880 millilitres of CO2 can be dissolved in a litre of H2O); does not support combustion, flames are extinguished at volume concentrations of 8 – 10 per cent carbon dioxide in the air. (Important note: we are in danger of falling unconscious at concentrations of 6 per cent in the air we breathe, even higher concentrations are fatal!) • At 20 degrees, CO2 can be liquefied at a pressure of 55.4 bar. In the case of a rapid drop in pressure, so much evaporation coldness is produced that the temperature cools down to below -80 degrees and solid carbonic acid snow develops – which is the way that CO2 fire extinguishers work. If the temperature increases to more than -78.464° (sublimation point), dry ice turns directly into gas again – without an intermediate liquid phase. • CO2 gas is very stable when heated; it only splits up into carbon monoxide and oxygen gradually at temperatures of more than 2,000 degrees. • CO2 is responsible for about 20 per cent of the natural (geogenic) greenhouse effect and about 60 per cent of the greenhouse effect caused by human beings (anthropogenic). It takes an average of 120 years to degrade in the atmosphere. • Anthropogenic CO2 production most recently amounted to more than 33 gigatonnes per year. The immense volume of 550 gigatonnes is produced every year geogenically; this is, however, compensated for by natural consumption of approximately the same amount, particularly by plants (photosynthesis) and calcifying organisms.

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  • #Lifestyle #Material Design #Innovations & Inventions

    Nylon in film

    In cinema, nylon was far more than just a fabric for clothing: nylon stockings became an eye-catching feature on film posters, a futuristic material and even a murder weapon in crime films.

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  • A robot with a human face

    Source: Technische Universität München Robotics researchers in Munich have joined forces with Australian and Japanese scientists to develop an ingenious technical solution that gives robots a human face. By using a projector to beam the 3D image of a face onto the back of a plastic mask, and a computer to control voice and facial expressions, the researchers have succeeded in creating Mask-Bot, a startlingly human-like plastic head. Yet even before this technology is used to give robots of the future a human face, it may well soon be used to create avatars for participants in video conferences. The project is part of research being carried out at CoTeSys, Munich’s robotics Cluster of Excellence. Mask-bot can already reproduce simple dialog. When Dr. Takaaki Kuratate says “rainbow”, for example, Mask-bot flutters its eyelids and responds with an astoundingly elaborate sentence on the subject: “When the sunlight strikes raindrops in the air, they act like a prism and form a rainbow”. And when it talks, Mask-bot also moves its head a little and raises its eyebrows to create a knowledgeable impression. What at first looks deceptively like a real talking person is actually the prototype of a new robot face that a team at the Institute for Cognitive Systems (ICS) at TU München has developed in collaboration with a group in Japan. “Mask-bot will influence the way in which we humans communicate with robots in the future,” predicts Prof. Gordon Cheng, head of the ICS team. The researchers developed several innovations in the course of creating Mask-bot. The projection of any number of realistic 3D faces is one of these. Although other groups have also developed three-dimensional heads, these display a more cartoon-like style. Mask-bot, however, can display realistic three-dimensional heads on a transparent plastic mask, and can change the face on-demand. A projector positioned behind the mask accurately beams a human face onto the back of the mask, creating very realistic features that can be seen from various angles, including the side. Many comparable systems project faces onto the front of a mask – following the same concept as cinema projection. “Walt Disney was a pioneer in this field back in the 1960s,” explains Kuratate. “He made the installations in his Haunted Mansion by projecting the faces of grimacing actors onto busts.” Whereas Walt Disney projected images from the front, the makers of Mask-bot use on-board rear projection to ensure a seamless face-to-face interaction. This means that there is only a twelve centimeter gap between the high- compression, x0.25 fish-eye lens with a macro adapter and the face mask. The CoTeSys team therefore had to ensure that an entire face could actually be beamed onto the mask at this short distance. Mask-bot is also bright enough to function in daylight thanks to a particularly strong and small projector and a coating of luminous paint sprayed on the inside of the plastic mask. “You don’t have to keep Mask-bot behind closed curtains,” laughs Kuratate. This part of the new system could soon be deployed in video conferences. “Usually, participants are shown on screen. With Mask-bot, however, you can create a realistic replica of a person that actually sits and speaks with you at the conference table. You can use a generic mask for male and female, or you can provide a custom-made mask for each person,” explains Takaaki Kuratate. Use in video conference In order to be used as a robot face, Mask-bot must be able to function without requiring a video image of the person speaking. A new program already enables the system to convert a normal two-dimensional photograph into a correctly proportioned projection for a three-dimensional mask. Further algorithms provide the facial expressions and voice. To replicate facial expressions, Takaaki Kuratate developed a talking head animation engine – a system in which a computer filters an extensive series of face motion data from people collected by a motion capture system and selects the facial expressions that best match a specific sound, called a phoneme, when it is being spoken. The computer extracts a set of facial coordinates from each of these expressions, which it can then assign to any new face, thus bringing it to life. Emotion synthesis software delivers the visible emotional nuances that indicate, for example, when someone is happy, sad or angry. Mask-bot can realistically reproduce content typed via a keyboard – in English, Japanese and soon German. A powerful text-to-speech system converts text to audio signals, producing a female or male voice, which can then set to quiet or loud, happy or sad, all at the touch of a button. But Mask-bot is not yet able to understand much of the spoken word. It can currently only listen and make appropriate responses as part of a fixed programming sequence. However, this is not something that is restricted to Mask-bot alone. A huge amount of research worldwide is still being channeled into the development of programs that enable robots to listen and understand humans in real time and make appropriate responses. “Our established international collaboration is therefore more important than ever,” explains Kuratate. The CoTeSys group has chosen a different route to researchers who use dozens of small motors to manipulate individual facial parts and reproduce facial expressions. Mask-bot will be able to combine expression and voice much faster than slower mechanical faces. The Munich researchers are already working on the next generation. Mask-bot 2 will see the mask, projector and computer control system all contained inside a mobile robot. Whereas the first prototype cost just under EUR 3,000, costs for the successor model should come in at around EUR 400. Besides video conferencing, “These systems could soon be used as companions for older people who spend a lot of time on their own,” continues Kuratate. Mask-bot is the result of collaboration with AIST, the National Institute of Advanced Industrial Science and Technology in Japan.

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  • More and more applications for plastic mone

    An attractive woman comes out of the water dressed only in a skin-tight bathing suit that emphasises her stunning figure. Her body and hair are still wet as she walks into a shop close to the beach to do some shopping. The salesman is puzzled, because it is obvious that she does not have a purse with her. When asked how she intends to pay, the beautiful woman gives him a seductive look and uses her deft fingers to pull out a rectangular piece of plastic – a credit card – that has been hidden between her bathing suit and right buttock. The salesman smiles in satisfaction. Credit cards are in widespread use throughout the industrialised world as a familiar way to pay without cash. In spite of the fact that they are so useful, they are sometimes known disrespectfully as plastic money since they are made from a polymer (PVC). Credit cards have many different advantages for users: the fact that water does not harm them is just one of them: neither the structure nor the quality of credit cards is damaged under the influence of moisture. Above all, however, it is possible to remain comparatively relaxed even if they get completely lost, provided their owner notices the loss quickly enough and has the card in question taken out of service by phone, e.g. via the central number (country code + 116 116). Abuse of the card by unauthorised third parties can be prevented effectively by doing this. Losing cash, on the other hand, has something depressingly final about it; the only hope the unfortunate loser generally has in this case is that the money is found and turned in by someone honest. Credit cards – a valuable innovation made of plastic Credit cards that make it possible to shop without cash have been on the market since 1950. The idea behind this form of payment came from the USA and was outlined as long ago as 1887 when the book “Looking Backward or Life in the Year 2000” was published by the author Edward Bellamy. The first card was issued by the credit card company Diners Club Inc. to its particularly credit-worthy customers. Owners of a credit card were therefore demonstrating their strong financial position, so that credit cards were also considered to be a status symbol. In addition to this, owners could use them – starting in the United States of America and then later all over the world too – to buy goods and services from the company’s contractual partners by adding their signature to the invoice. There are many different plastic money cards in the meantime: Master and Visa cards, American Express and various bank cards. Their simplicity, functionality and practicality might suggest that money cards have the potential to replace cash as the classic means of payment. As we all know, this is not so, however. The saying “Cash is king!” still applies today. Large amounts in small notes are extremely popular particularly – but not only – with crooks. To get rich illegally, plenty of criminals therefore attempt to master the difficult art of printing money in dark cellars and other secret places – with varying degrees of success. At first glance, it appears that all that is needed for this purpose is suitable paper, appropriate inks, a colour copying machine and a certain amount of skill and talent. Counterfeit money is not, however, quite as easy to print as it sounds. Some ingenious characters with enough criminal energy and ability nevertheless manage to make and distribute counterfeit money successfully. Greater security in monetary transactions thanks to polymer materials But how can banknotes be made forgery-proof? Canadian financial experts, chemists, physicists and engineers asked themselves this question when the proportion of counterfeit money circulating in the country reached a historical high: in 2004, there were 470 forged banknotes for every one million genuine ones. The Bank of Canada responded. On the one hand, it started to train retailers to identify counterfeit notes. On the other hand, it set itself the goal of making counterfeiters’ lives more difficult – by introducing banknotes made from polymer materials. The idea of plastic banknotes is not new; synthetic banknotes can be found in the wallets of consumers in many different countries around the world nowadays, including New Zealand, Romania, Taiwan, China, Ireland, Israel and Paraguay. Australia pioneered this development, incidentally. When the country switched its currency from the Australian pound to the Australian dollar in 1966, it wanted to present the most forgery-proof notes in the world. Counterfeiters evidently took this announcement as a challenge to prove the opposite, because the first forged banknotes were already circulating within the country after only a short time. In 1988, Australia finally introduced plastic banknotes that not only have more security features than paper notes thanks to the material used, such as holograms, windows and embossed patterns: “In addition to this, the environmental impact of polymer banknotes is considerably lower than of paper notes”, the Bank of Canada explains in a press release. The company also predicts that the new plastic banknotes will stay in circulation at least 2.5 times as long as paper notes. Quite apart from this, banknotes made of plastic retain value after they are taken out of circulation too. At the end of their useful life, plastic banknotes can, finally, be melted down or granulated and then be brought back into circulation and use as recycled material. Which only goes to show: money is particularly valuable when it is made from a polymer.

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  • Pros and cons of plastic bags

    Arguments for plastic bags (against a ban) - Low production costs, only a few chemicals are needed - Production requires little energy and generates only low emissions - Low weight, high strength - Resistant to water and chemicals - Easy to process, can be sealed - Fundamentally recyclable Arguments against plastic bags (for a ban) - Most plastic bags are only used once - The raw material is crude oil, i.e. a finite resource - It takes centuries for plastic bags to rot - Pulverised plastic waste in the sea gets into the food chain - Corn grown for the production of bioplastic reduces the land available for growing food for humans and animals Facts and figures - On average, plastic bags are used for 25 minutes - Depending on the type of plastic, it takes between 100 and 500 years for a plastic bag to disintegrate - One million plastic bags are in use around the world every minute - Three billion plastic bags are consumed in China every day. By way of comparison: the figure in Australia is four billion – per year! - 3.4 million tonnes of plastic carrier bags are produced in the European Union per year (data from 2008). This corresponds to the weight of more than two million cars - The average European uses about 500 plastic bags per year, including thin fruit and vegetable bags. The most recent figure for per capita consumption in Germany was 65 per year

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  • Plastic bags on trial

    Plastic bags on trial EU Commission considers ban “Plastic bags are the most excessive expression of consumer society”, the “Süddeutsche Zeitung” criticises. While the environmental organisation “Robin Wood” adds: “Plastic bags don’t belong on rubbish dumps; they should instead become a thing of the past – as quickly as possible”. The image of plastic bags has been ruined ever since the environmental movement succeeded in ingraining the slogan “jute instead of plastic” in the hearts and minds of many people. They are bought and used even so; after all, they are practical and convenient. The problem: they are used on average for less than 30 minutes and generally end up in the dustbin after they have been used just once. One million plastic bags are in use worldwide per minute (!). To meet the demand in the EU, our continent produces plastic carrier bags with a total weight of two million cars every year, i.e. the incredible amount of 3.4 million tonnes (data from 2008). The wasteful use of plastic has prompted the EU Commission to take action. The alarm is sounded in the 171-page report “Plastic Waste in the Environment” that appeared in April 2011 ( http://ec.europa.eu/environment/waste/studies/pdf/plastics.pdf ) primarily because of ocean pollution. We are familiar with the phenomenon in the Pacific: under the influence of the currents, a floating island of plastic waste the size of Central Europe has formed between California and Hawaii, the weight of which is estimated to total three million tonnes. It is frequently the case that whales, seals and sea turtles confuse plastic bags with jellyfish, so that they eat them and die. Birds swallow indigestible pieces of plastic or feed their young with them. Another problem: plastic does not disintegrate in water; it is merely pulverised, which can take centuries. It gets into the food chain as a result, including additives that may be toxic. There are already six kilograms of plastic in the Pacific Ocean for each kilogram of plankton ... Not a problem for Europeans, one might be tempted to think, but the territorial waters of the EU are affected too: scientists have counted an average of 115,000 plastic particles per square kilometre off the coasts of France and Italy. The total weight of the plastic particles currently floating in the Mediterranean is estimated to be 500 tonnes. Italy, which is the front runner in Europe with an annual consumption of 20 billion plastic bags, has taken action in the meantime, imposing a ban that took effect at the beginning of the year. As a result of this, conventional plastic bags have disappeared from retail outlets and have been replaced by ones made from compostable bioplastic produced, for example, from corn starch. There has already been a complete ban in France since 2010, with Paris initiating the development as long ago as 2007. Two petitions have in the meantime been submitted to the German Parliament that urge a ban to be imposed on plastic bags (Petition 3398 of 22.3.2009 and Petition 9937 of 8.2.2010, signed by the petitioners and 2,967 co-signers), but parliament has not responded yet. At the international level, it is not we Europeans who are pioneering such bans anyway; this “honour” goes to countries in Africa (e.g. Rwanda, Congo and Tanzania) and Asia (Bangladesh, Bhutan and Papua New Guinea, for example). Austria and Australia are leaning towards a total ban at the moment too, something that has already been done in a number of the Australian territories. In the USA, bans have only been introduced on plastic bags so far in the Californian cities of San Francisco and Los Angeles. The distribution of plastic bags free of charge is prohibited in almost half of the world in the meantime. Since 2008, this has been true of China as well, where – according to Western press sources – more than 1,000 billion (!) plastic bags were consumed per year. The retail trade even makes exceptions in Germany, however: whereas supermarkets demand payment for plastic bags, such outlets as department stores, shoe shops or pharmacies quietly provide them free of charge. The European Commission is no longer willing to stand on the sidelines watching the sometimes more and sometimes less systematic action taken by individual member states; instead of this, its aim is to introduce EU-wide rules to reduce plastic bag consumption. From 17. May to 9. August 2011, every EU citizen was therefore invited to participate in an online survey in English ( web-based consultation ): “The European Commission is asking the public [...] if charging and taxation would be effective, or if other options such as an EU-level ban on plastic carrier bags would be better.“ A total of 15,338 replies were received. 96.9 per cent came from private individuals, while the rest were accounted for by industrial associations, non-governmental organisations (NGOs), universities etc. The most important results: 70.55 per cent of the participants were in favour of a EU-wide ban on plastic carrier bags. 61.80 per cent agreed that an increase in the cost of plastic bags would lead to a reduction in their use (up to now, PE or PP bags, which are unbeatably inexpensive to produce, are always provided at lower cost than the alternatives made from bioplastic, paper or cotton). It is in addition important to the majority to have the choice when shopping between plastic bags that are biologically degradable and ones that are not biologically degradable. The EU Commission is not expected to take a decision before 2012, because the arguments pro and contra (see boxes) deserve to be considered carefully. Experts think that a ban on conventional plastic bags is unlikely, however, even if “the man or woman on the street” appears to be in favour of one. Because there are no signs of a political majority for a ban, either in Brussels or Berlin. So far, the NPD is the only party that is demanding a complete ban on plastic bags in Germany; “Die Linke” is in favour of a restricted ban and the Green Party is considering the ban option, although it favours taxation along the lines of the Irish model (in Ireland, there has been a raw material tax on every plastic bag since March 2002, when it was 15 cents, with an increase to 22 cents in July 2007; the result has been a reduction in annual consumption from 328 bags per capita to 21). None of the alternatives is likely to find a majority at national or European level – what is involved is an unbiassed evaluation of the environmental acceptability of plastic carrier bags and the alternatives to them. If the life cycle analyses are compared, plastic bags perform better than many critics would like us to believe, as soon as the energy consumed in production is taken into account too: Comparison with paper bags: paper is not preferable to plastic, because it takes almost twice as much energy to produce paper bags. Another disadvantage is the considerably higher pollution of air and water by nitrogen oxides, sulphur dioxides and other chemicals with which pulp fibres need to be treated. In addition to this, paper can only be reused to a limited extent, i.e. until it tears or gets wet. Whether paper bags are better or worse than plastic bags in individual cases depends on the raw material used (recovered paper, recycled plastic) and the disposal process. Comparison with cotton bags: cotton carrier bags have a positive image, but are not environmentally friendly per se; an investigation by the Federal Laboratories for Material Testing and Research at Zurich Technical University in Switzerland has revealed that this is only the case after they have been reused at least ten times – and only on the condition that plastic carrier bags in contrast really are only used once in each case. Comparison with bioplastic bags: the German environmental agency concludes that “bags made from biologically degradable plastic are not an environmentally sound alternative to bags made from conventional plastic”. One of their shortcomings is the loss of food-growing land (corn, sugar beet) and the large amount of fertilisers, pesticides and energy required to produce the raw materials – before the actual manufacturing process even begins. Another problem is that bioplastic is biologically degradable but is generally sorted out by composting plants even so, so that it ends up in incineration plants. Explanation: bioplastic rots more slowly than other organic waste, so that a time problem is created. Operators are also afraid that confusion might occur and that conventional plastic bags, i.e. ones that are not biologically degradable, are wrongly added to organic waste. If organic bags are incinerated, they do at least help to generate electricity. No pollutants are released apart from carbon dioxide, that is released during composting as well. According to the English/Welsh environmental authorities, there is a tie between the incineration of conventional plastic bags and the composting of bioplastic when all the environmental impact is taken into consideration – both of them are equally good or, if you like, equally bad. The German environmental agency also points out that the use of bioplastic bags might make consumers less environmentally sensitive: “It is after all particularly important to make sure that consumers do not think they can have a clear conscience when they simply throw the bags away wherever they are out in the country.” The possibility of inaccurate claims is another factor that has to be considered: compostable plastic bags are not by any means 100% organic; only about half of them is accounted for by corn starch, polylactic acid or similar appetisers for the microbes in compost that digest the plastic. Although the other half of the bag is also biologically degradable, it has been obtained from crude oil – this is the only way to make the material flexible enough. In view of all this, the German environmental agency thinks that it is “not necessary” to impose a general ban on PE or PP plastic bags, particularly in view of the fact that the recycling level in the German ‘dual system’ is higher than elsewhere at 70 per cent. It is only 20 per cent in some European countries, on the other hand – which means that there really is a need for action to be taken at EU level. Because plastic bags really do pollute the environment in uncontrolled fashion after use in countries in which there are no such recovery systems. The conclusion for the consumer is: the perfect shopping bag does not exist; what is crucial is reuse. “Reuse is the best alternative!” is how the German environmental agency summarises the situation. What is important to combat is not plastic but the throw-away mentality: irrespective of what it is used for, plastic is a valuable material that does not belong in the dustbin after it has been used once. The Internet platform oekowatch.org, which describes its principle as “to question political demands in the environmental field critically and free from ideological bias”, considers a possible ban on plastic bags to be a “regulation that misses the target”: “Anyone who wants to shop environmentally correctly just needs to act in an economically sensible way and reuse the plastic bag he or she is given free of charge or for a few cents. That way, the costs of substantially more expensive cotton bags or the higher price of paper bags are avoided and environmental pollution is reduced.” While it is reported in “Zeit Wissen”, a magazine that appears every two months: “Anyone who is afraid of climate change, should use his plastic bags as often as possible, irrespective of whether they are organic or PE”. Incidentally: plastic bags with the “Blue Angel” mark help to minimise carbon dioxide emission into the air and to reduce oil consumption – recycled plastic accounts for 80 per cent of them.

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  • Clean touch: germ-free plastics

    Topic of the Month September 2011 Clean touch: germ-free plastics Sports clubs, trams, public toilets: there is a risk of infection at any of the places that thousands of people frequent day in, day out. A slimy coating (“biofilm”) containing what are sometimes pathogenic bacteria and fungi that reproduce readily develops on door and grab handles or sanitary fittings as a result of repeated skin contact. A fleeting touch and the germs have already been passed on: unless hands are washed thoroughly, the germs get into the body and represent a particular danger to people with weakened immune systems – they face the threat of severe illnesses, from heavy diarrhoea to meningitis. So is it always necessary to reach for a disinfectant spray? A simpler solution is if the materials used have an integrated antiseptic, i.e. germicidal, function. Hygiene is a serious problem, particularly in hospitals, where more and more extremely dangerous pathogens can be found, such as the multi-resistant bacterium Staphylococcus aureus (MRSA) that causes pneumonia and carditis and cannot be treated successfully with antibiotics any more. According to the European Centre for Disease Prevention and Control (ECDC), about 50,000 of the roughly three million infections that occur in European hospitals every year are fatal. There are dangers everywhere. The U-shaped pipes (traps) located underneath the washbasins in patients’ rooms are an underestimated source of pathogens, for example. The magazine “Management & Krankenhaus” warns that the liquid retained in the trap contains up to ten billion living germs per millilitre. It is reported that aerosol formation leads to the transfer of them to the hands of hospital staff, where Pseudomonas aeruginosa – which causes urinary tract infections, pneumonia and meningitis – survives for longer than an hour. Enough time to be passed on to patients during care activities. Nosocomial infections (the term comes from the Greek words “nosos” = “illness” and “komein” = “care”) are also attributable to contaminated medical devices, drugs and food. Killing germs and interrupting transmission channels is therefore the name of the game in hospital hygiene. All objects and surfaces on which biofilms can form – particularly when they are made of plastic, which has surfaces that are anything but smooth and which microorganisms find it easy to settle on – are candidates for physical and/or chemical disinfection measures, such as heating, irradiation, wet and dry sterilisation. It proves to be a problem to fight contamination by conventional means, because disinfectants containing chlorine are very hard on polymer construction and other materials such as drinking water pipes: the surface of the material corrodes, roughens and repels dirt less effectively, creating an environment in which bacteria can thrive particularly well. Since plastic is so versatile and economic that it can only be substituted by other materials to a very limited extent, it is not uncommon for different processes to be needed to guarantee freedom from germs. • Antimicrobial metal coatings are one option. The Hygiene Institute at Leipzig University has found out that the survival rate of, for example, Escherichia coli (which as EHEC causes diarrhoeal disorders), Pseudomonas aeruginosa (see above), Staphylococcus aureus (see above) and Candida albicans (mucous membrane infections; pneumonia) is only half as high on chromium/nickel compounds we call stainless steel as it is on plastic. The mortality rate of Escherichia coli on stainless steel is apparently more than 99 per cent after two hours’ drying time. Other germs, on the other hand, such as the dangerous MRSA, survive on stainless steel for several days. Copper can deal with them better; in laboratory studies, MRSA died within two hours on high-density copper coatings. The germicidal properties of copper have, incidentally, been known since ancient times. The Greeks and Romans used copper vessels for drinking water to disinfect it and to keep it free from germs. • What are known as sol-gel coatings can even be sprayed on or applied via immersion baths. Geometrically complex objects are easy to provide with antimicrobial surfaces in this way too. • Compounding goes a stage further: plastics themselves are given antimicrobial properties while they are still being manufactured when additives are included in the process. For this purpose, germicidal substances are, for example, incorporated in polyethylene, polypropylene or polyamide, where they then have a disinfectant function thanks to the ongoing release of ions. Not only zinc oxide but also and above all silver are used in this context; the Chinese were already making acupuncture needles from the latter thousands of years ago. In addition to silver tableware and containers, silver coins were a popular disinfectant up to and including the 19th century, being put in water or milk. Modern processes are based on sterilising silver ions that diffuse from the material matrix to the surface and have an antimicrobial effect there: the cell membrane is destabilised, while metabolism and reproduction are disrupted at the same time, so that the microbe population is destroyed. A distinction has to be made between two different methods of operation: 1. Contact sterilisation: the microorganisms die when they come into contact with the antimicrobial additive on the surface of the plastic object. The substance is not released; it remains firmly bonded to the surface. 2. Release sterilisation: the anti-microbial substance is released on the surface and migrates into the immediate surroundings as nanoparticles. Since each kilogram of plastic contains a few hundred milligrams of silver at most, enhancement by the noble metal component remains inexpensive. Polymers that in themselves already have antimicrobial properties, such as polyammonium salts or polyethylene glycol, manage without such additives. They are a convenient way to produce soft coatings for metals, glass and ceramics that are UV-resistant and can even provide protection against corrosion. Since there is a choice of high-gloss, matt, smooth or structured surfaces and the material can in addition have whatever colour is needed, decorative requirements can be met too. Research scientists from the University of Massachusetts have adopted an innovative approach: they have developed polymers that imitate naturally antimicrobial substances (peptides), i.e. the compounds that form the first line of defence against infections in human beings and animals. The scientists found an ingenious way to do this: instead of imitating the peptides chemically, they just copied their surface structure. As soon as a microbe latches onto the plastic now, the latter perforates its cell membrane and the germ dies. The potential applications range from antiseptic kitchen tables to the equipment used in operating theatres. Products made from practically all materials and used in practically all areas of life are being given better antimicrobial properties in the meantime. Measures taken to eliminate germs in the food industry, such as coatings for the inside of beverage cans, extend shelf life and help to economise on preservatives that can cause allergies. Making socks, shoe inlays, mattresses or upholstered furniture germ-free prevents unpleasant odour formation, for which bacteria are responsible that interact with the sweat. The demand for antimicrobial plastic is probably strongest in the medical community. Wound dressings contain silver additives that are found in a similar form in the plastic containers used to store contact lenses too. Clinical studies have shown that catheters with a silver sulfadiazine coating can reduce vein infection rates by almost a factor of 5. In orthopaedic engineering, silver has recently been introduced as an antibacterial substance in the plastic shafts of prosthetic limbs, in order to counter odour formation and inflammation. According to the manufacturer, the technology reduces colonisation by the bacterial strains Staphylococcus aureus and Escherichia coli by 99.9 per cent. Last but not least: a self-disinfecting film that can be stuck, for example, to door handles and sanitaryware is an effective way to prevent germs from being passed on in hospitals. It has been developed at the Institute for Chemistry and Bioengineering Sciences at Zurich Technical University (ETH) in Switzerland. The film is coated with silver and calcium phosphate; according to ETH, the combination of both substances is up to 1,000 times more deadly to Escherichia coli than conventional silver products. The background: calcium phosphate is a welcome food source for the bacteria, which consume it eagerly. When the substrate material breaks down, the integrated silver particles are released; they have a toxic effect on the bacteria, however, so that the latter can be depended on to eat themselves to death by consuming the calcium. In other words, the crucial feature of the process is that the bacteria initiate the germicidal effect themselves and in fact control it, because silver is only released to the extent that bacteria are present to consume the calcium phosphate. Copyright: GD

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  • Still open to the public until 30. October: plastic-based art underground in Thuringia

    “Chandelier” by Martina Becker, Berlin (www.martinabecker.de); material: recyclable plastics; exhibition location: Cellar E, Greizer Strasse 37 (entrance: Museum für angewandte Kunst) Plastic-based art goes underground: more than 50 different installations created by artists from Europe and Eastern Asia are still on show at a very unusual place in Gera – the third-largest city in Thuringia / Germany – until the end of October: not in a museum but in five of the 220 “Höhler” (beer cellars) underneath the old part of the city. “Höhler” is the name given to vaulted cellars that were built in the Zechstein rock up to eleven metres deep underneath the houses in Gera to store beer from the end of the 16th century onwards. Since the local wine did not taste particularly good, Gera turned to beer instead in the late Middle Ages: hops were planted in the vineyards instead of grapes and all the house owners were granted the privilege of brewing and even selling beer (Gera “brewing rights” of 1487). Since more cool and dark locations were therefore needed, in which the beer could be stored for a longer time, the “Höhler” cellars were built. Nowadays Gera is overshadowed as a black beer city by its neighbour Bad Köstritz and the cellars have not been used to store beer for a long time now. In the Second World War they proved to be very effective bomb shelters and many of them were connected together to create escape routes in case some of them caved in – the result is an extensive labyrinth of underground passageways nine kilometres long with enchanting little niches that has in the meantime been discovered not only by tourists but also by artists: in 2003, the association dedicated to preserving the cellars co-operated with the town authorities to launch the “Höhler Biennale”. Since then, a Gera jury has screened hundreds of applications every two years, then choosing the installation artists whose works fit in best with the genius loci, i.e. that make the most of the cellar environment and that are particularly effective works of art in these surroundings. 5. Höhler Biennale The Höhler Biennale is already being held for the 5th time this year: its patron is Christine Lieberknecht, the Prime Minister of the State of Thuringia. 54 artists are using light and shade, silence and sound, the medieval and the modern, minotaurs and olms to present their installations underneath the city in Thuringia. They also focus on the concept of the underworld and various ideas that are associated with it: a hidden empire, a place for things that should not be seen, a hiding place, a dungeon, a grave, an abode for the dead – Hades as it was known to the Greeks – but also a place of pulsating life, where Eros reigns unhindered. It is no coincidence that plastic dominates as the material used to create many of the works of art in the cellars: where the titillating (“Hades der Dessous” by Ursula Reindell) meets the worn and old (Martina Becker’s chandelier decorated with plastic waste), it is only natural that plastics play a prominent role. Even the recycling concept has its place in the context of “Eros and death”: “die and become ...” A visit to the Höhler Biennale is not just an intellectual experience, however; it appeals to all the senses: in the dimly lit corridors which have to be negotiated to get from one work of art to the next, one loses one’s sense of time and self-perception increases. “The visitor becomes part of the works of art”, as Dr Gitta Heil, director of the Höhler Biennale, points out. The 5th Höhler Biennale started on 24. June and ends on 30. October (opening times: Wednesday to Sunday 10-18:00). Admission to all five exhibition cellars costs € 5; catalogue: € 10. Further information is available in the Internet: www.hoehlerbiennale.de, www.gera-hoehler.de

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  • Synthetic eye prosthesis

    For many patients who become blind after an accident or illness, a corneal transplantation could restore the ability to see. Each year, 40,000 people in Europe – in Germany, about 7,000 – await the opportunity to be able to see again, thanks to cornea donors. But donor corneas are not common. Dr. Joachim Storsberg of the Fraunhofer Institute for Applied Polymer Research IAP in Potsdam-Golm developed material and production process for a corneal prosthesis made of plastic. These can help patients who are unable to tolerate donor corneas due to the special circumstances of their disease, or whose donor corneas were likewise destroyed. The miniscale artificial cornea has to meet almost contradictory specifications: On the one hand, the material should grow firmly together with the cells of the surrounding tissue; on the other hand, no cells should settle in the optical region of the artificial cornea - i.e., the middle - since this would again severely impair the ability to see. And: The outer side of the implant must be able to moisten with tear fluids, otherwise the implant will cloud up on the anterior side. This would consequently require the patient to get a new prosthesis after a relatively brief period of time. And: The outer side of the implant must be able to moisten with tear fluid, so that the eyelid can slide across it without friction. Dr. Storsberg found the solution with a hydrophobic polymer material. This material has been in use for a long time in ophthalmology, such as for intraocular lenses. In order for it to satisfy the various characteristics required, complex development steps were necessary. The material was thoroughly modified on a polymer-chemical basis, and subsequently re-tested for public approval. In order to achieve the desired characteristics, the edge of the implant was first coated with various, special polymers. Then, a special protein was added that contains the specific sequence of a growth factor. The surrounding natural cells detect this growth factor, are stimulated to propagate and populate the surface of the corneal margin. Thus, the cells of the surrounding tissue grow with the implant, and the artificial cornea attains stability. The eye prosthesis evolved jointly with physicians and manufacturers in the EU project, „Artificial Cornea." The interdisciplinary research team needed three years to develop the artificial cornea. In a first step, they sent the chemical-biomimetic coated implant to Dr. Karin Kobuch of the Poliklinik für Augenheilkunde at the Regensburg University Medical Center and to the medical center at the Technical University of Munich, on the right banks of the Isar river. The physician examined the artificial corneas in dissected pigs eyes and specialized cell cultures. Eventually, the team under Dr. Gernot Duncker and Dr. Saadettin Sel of the University Center for Ophthalmology in Halle (Saale) tested the more complex models in rabbits. There, the design was further refined: the optics were made smaller, and the implant haptic enlarged in order to maintain a more stable construction. Quelle Fraunhofer-Gesellschaft http://www.k-online.de

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