How certified biodegradable plastics contribute to Circular Economy
BASF has been researching biodegradable and bio-based polymers for more than 30 years. The continuous development of these high-quality and high-performance materials takes place in close cooperation with customers, research institutes and local authorities. The focus always lies on the best environmental performance, no matter if the product is manufactured from fossil or renewable resources. For each individual application, environmental safety, cost efficiency and the social consequences have to be examined for a product’s entire life cycle in order to find the most suitable material for the right application with the greatest benefit for society. It should also be checked to what extent the biodegradability offers an added value.
Bioplastics do not substitute conventional plastics but complement them as special materials which offer new properties and application possibilities. They are, for example, the optimal solution for organic waste bags, compostable fruit and vegetable bags, compostable food packaging or agricultural mulch films. Correctly employed, biopolymers can contribute to reducing food waste, returning nutrients to the soil by means of greater volumes of compost generated and to avoiding the accumulation of plastics in the soil.
Thus bioplastics can make an important contribution to Circular Economy which has the aims to use products in the best way possible across the entire value chain, to keep them in usage for as long as possible and to recover them at the end of their service life.
Two different product groups fall under the term “bioplastics”: “biobased” plastics and “compostable” plastics.
Bio-based plastics are partly or entirely made of renewable raw materials. Polylactic acid (PLA), polyhydroxyalkanoate (PHA), starches, cellulose, chitin and gelatin for example, belong to this group. Bio-based plastics can be biodegradable – but they are not always. Among the bio-based but not biodegradable plastics are biopolyethylene, natural fiber plastics and composites of wood and plastic.
Biodegradable and compostable plastics can be biodegraded by microorganisms. Special bacteria give off enzymes which break down the material’s flexible polymer chains into small parts. These are then digested by the bacteria together with other organic material such as organic waste. Water, carbon dioxide and biomass remain. Compostable polymers can, but need not be produced from renewable raw materials. They can also be based on crude oil. The biodegradability does not depend on the raw material, it depends entirely on the chemical structure of the polymer.
The term „biodegradable“ is often used without clearly stating its meaning. It is important to always mention the environmental conditions where the biodegradation happens and how it takes place. Biological degradation depends on natural microorganisms. That is why any statement on the biodegradability can only be given for the respective environmental surrounding, which can be e.g. an industrial composting facility, a home-compost heap or agricultural soil. General statements on the environmental degradability cannot be regarded as reliable. The proof of the complete biological degradability is verified by independent certificates based on approved standards.
In different countries, there are special certification methods which independent institutes use to test biopolymers according to their biological degradability, chemical safety and eco-toxicity. Only when a material meets the clearly defined test criteria in standardized test conditions may it be marked e.g. as compostable or biodegradable in the soil.
EU: DIN EN 13432
USA: ASTM 6400
Japan: Green PLA
Australia: AS 4736
At the press conference in Dusseldorf, Katharina Schlegel from Global Market Development Biopolymers shows how ecovio® contributes to closing the nutrient cycle towards a circular economy.
BASF at K 2019:
Thin polyethylene (PE) mulch films are used by farmers in many countries to increase crop yield. However, after harvesting it is often impossible for farmers to collect these films completely, especially when they are only a few micrometers thin. PE residues therefore find their way into the soil and accumulate there, since they do not break down. Now a study from ETH Zürich, Switzerland, has shown for the first time that soil microbes can use films made from the plastic polybutylene adipate terephthalate (PBAT) as food. The microorganisms use the carbon from the polymer both to generate energy and to form biomass. This means that PBAT biologically degrades in the soil and does not remain there as microplastic as PE does.
For which applications is the use of biodegradable polymers sensible and truly sustainable? Industry, consumers and politicians are confronted with this question more and more frequently. BASF has competent experts that can support in eco-efficiency and life cycle analyses with in-depth knowledge. By comparing the ecological foot print of various product alternatives, it can be examined which product offers which kinds of environmental advantages.