Bio-based plastics are plastics made in whole or partially from biological resources.
Bio-based plastics are plastics made in whole or partially from biological resources.
The first known bio-based plastic, polyhydroxybutyrate (PHB), was discovered in 1926 by a French researcher, Maurice Lemoigne, from his work with the bacterium Bacillus megaterium. The significance of Lemoigne’s discovery was overlooked for many decades, in large part because, at the time, petroleum was inexpensive and abundant.
The petroleum crisis of the mid-1970s brought renewed interest in finding alternatives to petroleum-based products.
The rise of molecular genetics and recombinant DNA technology after that time further spurred research, so that by the beginning of the 21st century the structures, methods of production, and applications for numerous types of bio-based plastics had become established.
Bio-based plastics that were either in use or under study included PHB and polyhydroxyalkanoate (PHA), both of which are synthesized within specialized microbes, as well as polylactic acid (PLA), which is polymerized from lactic acid monomers produced by microbial fermentation of plant-derived sugars and starches.
Bio-based plastics currently make up an insignificant portion of total world production of plastics. Commercial manufacturing processes are expensive. However, improvements in metabolic and genetic engineering have produced strains of microbes and plants that may significantly improve yields and production capabilities while reducing overall costs. These factors, when added to increasing oil prices and growing environmental awareness, may expand the market for bio-based plastics in the future.
Properties can vary considerably from material to material.
Bio-based or partly bio-based durable plastics, so called "drop-in bioplastics” such as bio-based or partly bio-based PE, PET or PVC, possess identical properties as their conventional versions. These bio-based plastics cannot be distinguished from conventional commodity plastics other than by scientific analyses.
Bio-based plastics are mostly used in packaging which is the most dominant application for bio-based plastics and accounted for 70% of the overall market in 2010, including starch-blends, PLA, bio-PET, bio-PE. Bio-PP is still in a pilot phase. Besides packaging, PLA is also used as fibers in the textile sector.
Bio-based succinic acid is suitable for several applications in sports & footwear; automotive; packaging; industry; agriculture; non-wovens and fibers.
Bio-based specialty polyamides are used in the automotive and in sport & leisure sectors. PA 4.10 for example is applied in sports & leisure, automotive interior and exterior, consumer electronics and furniture.
Bio-based thermoplastic copolyester elastomers are used in high-tec applications like specialty packaging and alternative energy.
Natural bio-based polymers
These polymers are synthesised by living organisms, essentially in the form in which they are finally used. Examples of naturally produced bio-based polymers include;
• polysaccharides
• cellulose / starch
• proteins
• bacterial polyhydroxyalkanoates
After extraction and purification, direct industrial exploitation is possible.
Synthetic bio-based polymers
Polymers whose monomers derive from renewable resources but which require a chemical transformation for conversion to a polymer.
Many conventional polymers can, in principle, be synthesised from renewable feedstock. For example, corn starch can be hydrolysed and used as the fermentation feedstock for bio-conversion into lactic acid from which poly(lactic acid), PLA, can be produced through chemical processing. Although it's orgin is renewable the polymer cannot be consider 'natural' as it is synthesised within a chemical plant.
DEFINITIONS
What are bioplastics?
Many stakeholders use the general term "bioplastics” to describe two different concepts:
Biodegradable plastics –e.g. Starch, polyhydroxyalkanoates, polybutylene succinate - referring to end-of-life options and
Bio-based plastics – meaning plastics made from a renewable raw material source, e.g. bio-based polyethylene, bio-based polyamide, polylactic acid. It is important to understand that not all bio-based plastics are biodegradable (e.g. bio-PE) and that biodegradable plastics are not always bio-based but sometimes produced from fossil resources (e.g. biodegradable polyesters).It is essential to make this distinction in order to avoid confusion when addressing different societal and environmental concerns of bio-based and biodegradable plastics.
RESOURCE
What kinds of feedstock/biomass are used for the production of bio-based plastics?
Bio-based plastics can be made from a variety of renewable resources. The renewable resources used today are mainly derived from agriculture. The majority of production technologies for bio-based plastics available today are based on carbohydrate-rich plants such as grains, corn, potatoes, sugar beet/sugar cane or vegetable oils (e.g., soybean oil, castor oil, palm oil). Carbohydrates can also be obtained from non-food crops (e.g. arundo, cynara) and biomass from by-products like straws, and stalks. Continuing technological developments will make it economically viable to use second generation feedstock, based on lignocellulosic biomass.
How much biomass is used worldwide for the production of bio-based plastics? And how much arable land is used?
The annual global production capacity in 2011 of bio-based plastics was about 1 mioT Depending on the type of polymer and the crop used average yields range between 2 and 6 metric tons of bio-based plastic per hectare. The current global production capacity of bio-based plastics requires about 500,000 hectares of land[1], which corresponds to about 0.01% of available arable land (ca. 5 billion hectares) in the world[2].
Does the industrial use of biomass compete with food/feed productions?
Agriculture must aim primarily to supply food and feed. Compared to the use of biomass, for food, biofuels and other industrial use, the demand for renewable raw materials for the production of bio-based plastics is very small. Although the bio-based polymers market is forecasted to grow rapidly in the next decades, this growth will have only limited impact on the agricultural market overall. Nevertheless, if demand for renewable feedstock grows, this will inevitably lead to competition between food production and the material and energetic use of biomass. Good agricultural practice is part of the sourcing strategy of many companies, e.g., by applying supplier codes of conduct. The use of sustainability certification schemes is a useful tool towards the sustainable sourcing of biomass around the globe.1 Examples of biomass certification schemes are the ISCC (International Sustainability and Carbon Certification) and the RSPO (Round Table on Sustainable Palm Oil). Further, renewable feedstock of second generation, based on lignocellulosic biomass, will relieve the pressure on agricultural land used today for food production. PAGEV is aware that this is an ongoing learning process and that an open dialogue and commitment of all stakeholders in the value chain is needed to ensure sustainable production and consumption of renewable raw materials worldwide.
How is the European agriculture affected by the use of biomass for bio-based plastics production?
In a conservative scenario the area under agricultural cultivation needed to supply the current European production capacity (2011) can be calculated to be in the region of 107,000 hectares, which is ca. 0.05% of the total agricultural area available in EU 27 countries (the total agricultural land in Europe corresponds to 189 million hectares).(2)
Assuming continued high and maybe even politically supported growth of the bio-based plastics market at the current stage of technology, a production capacity of up to 283,000 tons might be achieved in Europe by the year 2016 (corresponding to 4.9% of the predicted global market capacity), which would account for a maximum of 141,500 hectares, or roughly 0,08 percent of the available farmland in Europe.(2) It is not yet clear to what extent an increased share of food residues, non-food crops or cellulosic biomass will lead to a reduction in the use of arable land for bioplastics.
Does the production of bio-based plastics require the use of genetically modified plants?
The use of GM crops is not a technical requirement for the manufacturing of any bio-based plastic commercially available today.
FUNCTIONALITY
What differentiates bio-based and biodegradable plastics from conventional plastics?
The term bioplastics covers plastics made from renewable resources (bio-based plastics), including plastics that biodegrade under controlled conditions at the end of their use phase. Biodegradable plastics may be derived from renewable resources such as starch, but may also be derived from fossil feedstock, e.g.polycaprolactone. On the other hand, some bio-based plastics have the same structure and material properties as conventional plastics, e.g., bio-polyethylene, bio-polyvinylchloride, bio-polyethylene terephthalate. In this case, the only difference compared to the conventional equivalent is the origin of at least part of their feedstock. There are also a number of bio-based plastics that have no conventional plastic equivalents. Examples are polylactic acid, certain polyamides as well as polyhydroxyalkanoates. These materials have innovative properties that bring additional value to the applications in which they are used.
What are typical applications for bio-based and biodegradable plastics?
Bio-based and biodegradable plastics offer a value proposition for a series of applications. Biodegradable plastics are used in single or short-term use applications such as organic waste collection and diversion, in agricultural and horticultural sectors (e.g., as mulch-films or plant pots) and in packaging applications. Bio-based, plastics can be used in long-lasting applications, such as: automotive, E&E, sports and leisure, and furniture. Due to the rapid growth of the sector and continuous innovations, a wider range of applications is expected to emerge in the coming years.
SUSTAINABILITY/RESOURCE EFFICIENCY
How do bio-based and biodegradable plastics contribute to resource efficiency and climate protection?
The use of renewable resources for the production of bio-based products is often seen as a means of reducing the dependency of the plastics industry on fossil resources. Furthermore, in some cases there may also be a contribution to climate protection through the reduction of greenhouse gas emissions, particularly CO2. However, as for any other material or product, environmental benefits need to be proven by a life cycle assessment approach. Like conventional plastics, bio-based plastics can be used to reduce energy consumption. For example, high performance bio-based plastics can replace some metal parts in transport applications hence reducing weight and energy consumption. The exploitation of biomass waste derived from agricultural productions and forestry, for the production of bio-based plastics could represent a significant contribution to resource efficiency (waste as feedstock for industrial use) and climate protection. It therefore merits further research efforts and technical development. Compostable plastic waste bags support clean separation and collection of organic waste and divert organic waste from landfill towards high-quality compost production. Composting is of particular importance when soil erosion is a serious problem, for example in some southern European countries. In the future, the European Union will require its member states to collect and dispose of organic waste separately. In Europe today, only 30% of compostable waste is separated from the rest[3] – many countries still deposit it in the same landfill with non-compostable waste. If all of Europe collected and composted its organic waste separately, greenhouse gas emissions from waste disposal could be reduced by 30%.[4]
Is it feasible and would it make sense to replace all conventional plastics with bio-based and biodegradable plastics?
No, this is neither feasible nor would it make sense. Nowadays the bio-based and biodegradable plastics market represents less than 1% of all plastics produced. Although production capacity is expected to grow at about 20% per year, bio-based and biodegradable plastics will continue to be a niche segment in the next few decades. Furthermore, plastics are resource efficient materials in many applications and help to save resources and improve quality of life in many ways during their use phase. Overall, the plastics industry should continue to strive towards a more efficient use of all kinds of resources, irrespective of their origin.
Are bio-based and biodegradable plastics more sustainable than conventional plastics?
PAGEV recommends that any product environmental impact should be measured using comprehensive Life Cycle Assessments together with cost evaluations. It is not correct to assume that bio-based and biodegradable plastics have by definition a lower environmental impact than conventional plastics.
TECHNOLOGY & MARKET
What is the production capacity for bio-based and biodegradable plastics (globally and by regions)?
A market study published by EuropeanBioplastics(2) estimated that in 2011 the global bio-based and biodegradable plastics production capacity amounted to 1,161,000 tons. Of this amount, biodegradable plastics (including non-bio-based) accounted for 486,000 tons of and bio-based (non-biodegradable) plastics for 675,000 tons. In 2011, the production capacity was distributed evenly between South America and Asia and on a minor extent between Europe and North America. However, the forecast for the year 2016 predicts significant growth of the Asian production capacity (the proportion of production capacity share is expected to increase from 34.6% in 2011 to 46.3% in 2016) and a progressive decline in the share of production capacity in Europe (from 18.5% to 4.9%).
How fast is the market for bio-based and biodegradable plastics expected to grow in the coming years?
Production capacity is forecasted to grow at about 20% per year until 2016, whereby the highest contribution to growth will come from bio-based (non-biodegradable) plastics.
Can bio-based and biodegradable plastics be processed with conventional plastics processing technologies?
Many bio-based plastics like bio-PE, bio-PET, bio-PA and bio-PVC have the same chemical and mechanical properties of the corresponding fossil-based materials. As a result, they can be processed in the same way as their conventional equivalents. Other bio-based and biodegradable plastics also offer drop-in solutions, and can be processed with existing equipment even though they do not have any fossil-based equivalents. As with any new material, it is not possible to give a generalized answer. The situation must be considered on a case-by-case basis.
END OF LIFE
Can bio-based and biodegradable plastics be recycled and disposed of in existing recycling schemes?
In plastics recycling, a distinction needs to be made between pre-consumer (post-industrial) material and post-consumer material. In principle, the technology of mechanical recycling is applicable to both bio-based conventional plastics and to most grades of biodegradable plastics. In particular, pre-consumer recycling of mono-material scraps is practiced in many cases, both for conventional plastics and for bio-based and biodegradable plastics. Products made with bio-based equivalents of conventional polymers (such as bio-PE, bio-PET, bio-PVC) do not differ from fossil-based products when it comes to mechanical recycling. Other polymers like PLA can also be recovered with mechanical recycling, especially when sufficient volumes of waste material are available, either through separate collection or through sorting routines in conventional recycling units. Certified compostable articles that are designed to be recovered by means of organic recycling are expected to be treated in composting plants or anaerobic digesters. Mechanical recycling is therefore not usually the ideal recovery option for these materials.[5] Feedstock recycling is another common form of recovery that can be applied to convert polymer chains back into the constituent units. This method is currently practiced for the recovery of polylactic acid (PLA). PLA can be hydrolyzed back into its monomer lactic acid and re-used to produce new PLA.
Are all bio-based plastics biodegradable?
While some bioplastics are biodegradable, some are not, namely the so-called ‘durables’. A traditional plastic based on fossil resources, such as polyethylene, is not biodegradable. Like conventional plastics, bio-based equivalents of traditional plastics, e.g., bio-PE, bio-PET, bio-PA, bio-PVC and other bio-based polymers do not biodegrade. Biodegradability is an intrinsic material property related to the molecular structure of the material and is independent of the origin of the material itself. Some modified traditional plastics are sometimes termed ‘degradable.’ For example, they may contain an additive which causes the plastic to degrade under the influence of ultraviolet light and oxygen. These are known as ‘photodegradable plastics.’ Other materials may contain an additive that initiates degradation under specific conditions of temperature and humidity. These are referred to as ‘oxo-degradable plastics,’ but the degradation process is not initiated by microbial action. This degradation process does not comply with the EN 13432 standard.
FOOTNOTES:
[1] If a yield of 2 metric tons biopolymer per hectar of land is considered.
[2] Source: a) European Bioplastics, 2012. b) „Globale landflächen und biomasse nachhaltig und ressourcenschonend nutzten", Umweltbundesamt, 2012, page 8.
[3] ORBIT e.V. / European Compost Network ECN ""Compost production and use in the EU", 2008.
[4] a) BASF Ecoefficiency analysis, 2011.
b) "Waste opportunities Past and future climate benefits from better municipal waste management in Europe” EEA Report /No 3/2011
[5] EuropeanBioplastics, Fact Sheets „Mechanical Recycling", 2010
