What are bioplastics? Tear-resistant waste bags for compost

The term “bioplastics” describes two groups of products – “bio-based” and “biodegradable” plastics. Biobased plastics are made either wholly or partly from renewable raw materials and include polylactic acid, polyhydroxyalkanoates, starches, cellulose, chitin and gelatine. Biobased plastics can also be biodegradable – but this is not always the case. Nonbiodegradable biobased materials include biocomposites and composite materials made from wood and plastic. Biodegradable plastic: Special bacteria release enzymes that break down the material’s long polymer chains into small parts that the bacteria subsequently digest and turn into water, carbon dioxide and biomass. To be designated biodegradable in line with the European standard DIN EN 13432, at least 90 percent of the material must have decomposed within 180 days under controlled conditions – high temperature and humidity, and defined oxygen levels. Once these standards are met, the product may display the seedling logo signifying compostability. Biodegradable plastics do not have to be made from renewable raw materials; they can also be petroleum-based. The raw material is unimportant; what matters is the chemical structure of the plastic. When is using bio-based and/or biodegradable plastic a good idea? There are no clear-cut advantages or disadvantages to using fossil-based or renewable raw materials per se. It is best to decide on a case-by-case basis, taking environmental concerns, cost-effectiveness and social impact over the entire product life cycle into account. BASF’s Eco-Efficiency Analysis has shown time and again that bio-based plastics are not always more eco-efficient than their petrochemical-based counterparts. If relatively little water and fertiliser are required, and transportation routes are short, using plant-based raw materials can be best for the environment. But if a large amount of energy is needed to process the materials, this beneficial effect can soon be reversed. Bio-degradable plastics are not necessarily more eco-friendly than other plastics. But for certain applications, they are the best solution – such as mulch films for agriculture, compostable food packaging or shopping bags. The latter have been available at discount supermarket Aldi Süd for the past few years: shoppers can use them a number of times before reusing them at home as compostable bin liners.