Bioplastics: an alternative with a future?

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1 Press Bioplastics: an alternative with a future? Plastics offer a broad spectrum of characteristics and applications and are today a key material for many branches of industry. Global demand is constantly growing and, with it, the expectations of the performance of this group of materials. In the last few years, rising crude oil prices have sharpened public awareness of the finiteness of fossil resources and strengthened the desire for greater climate protection and sustainability. And, within this group of materials, interest has been stimulated in the special category of bioplastics. As a complement and in some areas as an alternative to conventional plastics, they appear to be a logical and necessary step for a modern and forward-looking plastics industry. And they will also of course have their place at K 2013 in Düsseldorf from 16 to 23 October. Any discussion of the pros and cons, the future role and the market potential of bioplastics makes little sense without prior clarification of the meaning of the prefix bio-, says Prof. Dr.-Ing. Christian Bonten of the Institute of Plastics Engineering at the University of Stuttgart, expressing his reservations. For this is precisely where confusion arises. One prefix, two meanings: bio-degradable and bio-based plastics Biodegradable plastics Apart from small quantities of substances, biodegradable plastics consist of biodegradable polymers and additives. Special bacteria and their enzymes demonstrably convert biodegradable plastics into biomass, CO 2 or methane, water and minerals as soon as the macromolecules have been sufficiently fragmented by other degradation mechanisms. For a plastic to be termed compostable in Europe, 90 per cent of it must degrade in clearly defined conditions into fragments smaller than 2 mm within 12 weeks. Only then can composting facilities operate costeffectively and without disruption. Before bioplastics can be allowed to 1

2 enter the soil, proof must be additionally furnished that a certain heavy metal concentration is not exceeded and that the soil s fertility is not restricted. Products conforming in Europe to EN may be marked with the seedling, the European logo for compostability, on certification. In the USA there is also a standard for proven compostability, which is based essentially on the European standard. Contrary to popular belief, biodegradable plastics are not necessarily made from renewable resources and can also be derived from mineral oil. Biodegradability therefore depends not on the raw material, but on the plastic s chemical structure. Examples of biodegradable polymers are polylactides (PLA), polyhydroxyalkanoates (PHA), cellulose derivatives and starch as well as mineral-oil-based polybutylene terephthalate (PBAT) and polybutylene succinate (PBS). Non-biodegradable, on the other hand, are polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET) and polyamides (PA), for example. The term biodegradable is also used in different ways. There are conventional plastics containing only tiny quantities of biologically or otherwise degradable substances. In suitable conditions, these merely break down into smaller, barely visible constituents. However, they do not fully metabolise and the fragments accumulate in the soil and food chain over time. Consequently, the very fact that a product is biodegradable does not solve the problem of waste accumulation or litter in the countryside. Even biodegradable materials take weeks to decompose in defined conditions microorganisms, temperature and moisture. In the absence of these conditions, the plastic resists decomposition and biological degradation can take several years. Bio-based plastics Bio-based plastics, on the other hand, are renewable resources derived from nature. However, these are not necessarily biodegradable as well. The adjective bio-based merely tells us that the carbon atoms in the molecule chains come from today s nature and are thus bio. 2

3 Fossil hydrocarbons from mineral oil, natural gas and coal were also once nature. They stem from plants and algae that lived about 500 million years ago. Through drying, certain geological processes and bacterial decomposition in the absence of oxygen, they were converted into liquid fossils or fossil hydrocarbons. The bacteria involved in these prehistoric processes were not the same as those required for biodegradation today (see above). The combustion of fossil mineral oil, natural gas and coal releases the carbon dioxide that the plants extracted from the atmosphere for their own growth 500 million years ago. Today, however, it causes excessive concentration in the atmosphere and the familiar associated problems. We therefore have to distinguish between bad CO 2 from the past and good CO 2 in the present. In research and industry, there is growing interest in the use of renewable raw materials so as to reduce the consumption of fossil hydrocarbons and thus to release less historic CO 2 into the environment. At present, bio-based plastics are derived from different hydrocarbons such as those found in sugar, starch, proteins, cellulose, lignin, bio-fats and oils. Bio-based polymers include polylactides (PLA), polyhydryoxybutyrate (PHB), cellulose derivatives (CA, CAB) and starch derivatives as well as, for example, bio-polyethylene (PE). The latter is derived entirely from Brazilian sugar cane, has the same properties as conventional polyethylene, but is not biodegradable. The at least to some extent bio-based but not biodegradable polymers also include naturalfibre-reinforced conventional plastics along with polyamides and polyurethanes. Bio-based plastics can undoubtedly make a valuable, albeit relatively small contribution to improving the life-cycle assessment, as only a few per cent of the world s fossil resources are used for the production of plastics. Over two thirds are still used for energy generation and transport. From this it is obvious that bio-based plastics will hardly cause food shortages but more on this later. 3

4 Bioplastics global output The demand for plastics is steadily growing. For 2011, the manufacturers association PlasticsEurope put global polymer output at 280 million tonnes. Some 235 of these 280 million tonnes are used for plastics materials, and bioplastics have not so far figured highly in this survey. Because of the high market growth, European Bioplastics is forecasting world production capacity for bioplastics to reach roughly 5.8 million tonnes by The study of the nova institute of March 2013 is even more optimistic. According to its estimate, production capacity for biobased plastics will grow to over 8 million tonnes by 2016 and to roughly 12 million tonnes by The production of plastics based on renewable raw materials has risen very fast despite its low overall level compared to oil-based plastics. According to the manufacturers association European Bioplastics, biodegradable plastics accounted for several hundred thousand tonnes and thus the lion s share of total global capacity for bioplastics in Since 2010, the growth rates for biodegradable plastics have been far outstripped by those for bio-based plastics. According to association forecasts and despite constant growth, they will account for only about a seventh of overall bioplastics output by The far larger share of bioplastics will then be bio-based but not biodegradable. 4

5 Production capacity for biodegradable and bio-based plastics in 2011 with a forecast for 2016 (source: European Bioplastics; Hannover University of Applied Sciences and Arts, IfBB Institute for Bioplastics and Biocomposites) 5

6 Production capacity for various bioplastics in 2011 (source: European Bioplastics; Hannover University of Applied Sciences and Arts, IfBB Institute for Bioplastics and Biocomposites) There is a growing regional shift in the market shares of biopolymer production. While Europe s share of production capacity came to about 17 per cent in 2012, it will drop to about 5 per cent by the year 2016, according to a study by the Institute for Bioplastics and Biocomposites (IfBB). The IfBB expects Asia and South America to benefit the latter with a growth in production capacity from about 30 per cent in 2012 to over 45 per cent in Rising standards bioplastics are no exception For their growing technical applications, plastics have to meet increasingly high standards. And bioplastics are no exception. As far as reproducibility is concerned, they still have some catching-up to do, and in terms of barrier properties, durability and compatibility with other biopolymers and additives, there is still plenty of room for improvement. However, bioplastics have come a long way from the often poorperforming pure biopolymers of the first generation. Ultimately, however, the long-term success of bioplastics will depend on price, competitive production capacity and reliability. 6

7 Bioplastics and their applications today Biodegradable plastics are usually employed in applications where degradability proves to be particularly useful. This applies, for example, in agriculture to mulch films and plant pots that do not have to be collected and transported elsewhere after use, but metabolise on the spot in the soil to form biomass. In private households, degradable kitchen waste bags have conquered a market and can be composted together with their contents. Domestic/ Office Furniture/- Waste near-domestic supplies furnishings management products Watering cans, Writing Chairs (Compostable) vacuum cleaners, implements, waste bags and drinking straws correction bin liners rollers, rulers Agriculture/ gardening and landscaping Agricultural films and nonwovens, dispensers, plant pots Catering Construction Electrical items Disposable Tool handles, Housings for cutlery and dowels, bio-pu computer mice, crockery, insulation, keyboards, waste bags insulating telephones, materials, mobile phones, terrace surfaces, cable insulation carpeting and floorcoverings Current applications of bioplastics (source: Hannover University of Applied Sciences and Arts, IfBB Institute for Bioplastics and Biocomposites) Bio-based plastics are now also found in consumer electronics and automotive applications. The share of plastics in automotive engineering has been steadily rising over the last few decades. The percentage of bioplastics used here is now also growing. For its Sai hybrid car only available in Japan, Toyota, for instance, has developed interior 7

8 furnishings and equipment made of 80 per cent renewable raw materials, as of model year This has been made possible by the use of bio- PET, a plastic derived from sugar cane. It features temperature stability suitable for car interiors, a low tendency to shrink and good mechanical properties. Bio-PET s carbon footprint is said to be far smaller than that of its mineral-oil-based conventional equivalents. But PLA and polyurethane (PU) foam based on soya are also found today in a vast diversity of automotive components. Practically all car manufacturers make use of bioplastics in their vehicles and are working towards increasing their use. Mulch films of biodegradable PBAT/PLA compound can be ploughed in after the harvest and, unlike classical film, do not have to be first collected and then disposed of (photo: BASF SE). Transparent food film made of Bio-Flex A 4100 CL / F 2201 CL / A 4100 CL (photo: FKuR) 8

9 A paper cup coated with a film of plastic made of PBAT/PLA compound does not go soggy and can be industrially composted (photo: BASF SE). M440 ECO computer mouse housing made of Biograde Fujitsu) (source: Are bioplastics the only good plastics? In any blanket positive assessment of bio-based and biodegradable plastics, it is often forgotten that energy from fossil fuels is also used in their production be it in the sowing of crops, harvesting, transport, fermentation etc. It is therefore always essential to consider a product s entire life-cycle, because only then is it possible to conduct scientifically sound life-cycle assessment comparisons and arrive at a well-founded conclusion about a product s sustainability. Controversy over competition for agricultural acreage Whether agricultural land should be used for anything other than the production of food is a controversial issue. Here, again, it is worth taking a more discriminating look. Prof. Dr.-Ing. Christian Bonten of the Institute 9

10 of Plastics Engineering at the University of Stuttgart believes fears that food shortages could arise due to the use of carbohydrates for bioplastics to be unfounded. The fact that the world s energy needs cannot be met with carbon sources of plant origin is confused with the far lower demand for carbohydrates for the production of plastics, says Bonten. According to European Plastics, only 0.05 per cent of agricultural acreage in the European Union would have been required in 2011 to satisfy total global demand for bioplastics. In addition, for the production of bioplastics, it is already possible in some areas to use wastes from the farming industry. To prevent competition arising in the medium and long term, this raw materials avenue must be developed further. Similar views are expressed by Kristy-Barbara Lange, Head of Communication at European Plastics, in an interview with Messe Düsseldorf in May 2012: Intensive research and development are taking place in the bio-refinery sector to make it possible to tap second-generation raw materials such as cereal straw, maize straw and other cellulose-based materials as potential sources. As soon as these are established, Lange continues, a stream of fermentable sugars based on non-food cultivated plants will be available for energy, chemicals and polymers. As a result, there would be even less grounds for potential conflict over land use for food and raw materials. Finally, it can be said that nothing can stop the advance of bioplastics, bio-based or biodegradable. In many areas bioplastics are already a genuine alternative to conventional plastics and the view that they are not (yet) competitive can no longer be sustained. However, a panacea for all environmental problems they are not. Furthermore, the unqualified portrayal of bioplastics as being totally carbon-neutral is at the present time extremely premature. But they do pave the way into the post-oil era. Whoever wishes to find out about the prospects for and potential of bioplastics along with the latest developments and innovative applications will have plenty of opportunities to do so at the exhibitors stands at K The world s most important trade fair for the plastics and rubber industry is taking place this year in Düsseldorf from 16 to 23 October. 10

11 In addition, Bioplastics Business Breakfasts, brief seminars on selected industry topics, will be taking place from 17 to 19 October, daily from 8 to 12 h. August 2013 Contact Press Office K 2013 Eva Rugenstein/Desislava Angelova Tel Fax RugensteinE@messe-duesseldorf.de AngelovaD@messe-duesseldorf.de Further information or in the social networks Xing: Facebook: Twitter: 11