What are Bioplastics?
This article prepared by European Bioplastics e.V.
Bioplastics are a large family of different materials.
Bioplastics are not just one single substance, they comprise of a whole family of materials with differing properties and applications. According to European Bioplastics, a plastic material is defined as a bioplastic if it is either biobased, biodegradable, or features both properties.
Bioplastics are biobased, biodegradable, or both.
Biobased: The term ‘biobased’ means that the material or product is (partly) derived from biomass (plants). Biomass used for bioplastics stems from e.g. corn, sugarcane, or cellulose.
Biodegradable: Biodegradation is a chemical process during which microorganisms that are available in the environment convert materials into natural substances such as water, car bon dioxide, and compost (artificial additives are not needed). The process of biodegradation depends on the surrounding environmental conditions (e.g. location or temperature), on the material and on the application.
The property of biodegradation does not depend on the resource basis of a material but is rather linked to its chemical structure. In other words, 100 percent biobased plastics may be non-biodegradable, and 100 percent fossil based plastics can biodegrade.
Benefits of bioplastics
In search of new material solutions and keeping an eye on the goal of sustainable production and consumption, bioplastics have several advantages. The use of renewable resources to produce bioplastics is the key for:
- increasing resource efficiency by the means of:
• the resources being cultivated on an (at least) annual basis;
• the principle of cascade use, as biomass can first be used for materials and then for energy generation;
- a reduction of the carbon footprint and GHG emissions of materials and products;
- saving fossil resources by substituting them step by step.
Material types – three main groups
The family of bioplastics is divided into three main groups:
1. biobased or partly biobased, non-biodegradable plastics such as biobased PE, PP, or PET (so-called drop-ins) and biobased technical performance polymers such as PTT or TPC-ET;
2. plastics that are both biobased and biodegradable, such as PLA and PHA or PBS;
3. plastics that are based on fossil resources and are biodegradable, such as PBAT.
The potential of bioplastics will shape the future of the plastics industry.
The graph ‘material coordinate system of bioplastics’ below depicts common types of bioplastics and how they are classified according to their biodegradability and biobased content.
Examples of established bioplastic materials
Biobased, non-biodegradable polyolefines and PET (‘drop-in’ solutions)
Commodity plastics like PE, PP and PVC can also be made from renewable resources – most commonly from bioethanol. Bio-PE is already being produced on a large scale (200,000 tons p.a. by Braskem, Brazil; further projects planned by Dow Chemicals). Bio-PP and Bio-PVC are soon to follow that trend. The partially biobased polyester PET is used for both, technical applications and packaging (mainly for beverage bottles, e.g. the ‘Plant bottle’ by Coca-Cola). As the value-added chain only requires adaptation at the outset, while the properties of the products remain identical to their fossil versions, they are also referred to as ‘drop-in’ bioplastics. Accordingly, the period from development to commercialisation of these materials is considerably shorter.
Biobased, non-biodegradable technical/performance polymers.
This large group comprises many specific polymers such as biobased polyamides (PA), polyesters (e.g. PTT, PBT), polyurethanes (PUR) and polyepoxides. Their use is most diverse. Some typical technical applications are textile fibres (seat covers, carpets), automotive applications like foams for seating, casings, cables, hoses, and covers – to name but a few. Usually, their operating life lasts several years. Therefore, they are referred to as durables, and biodegradability is not a sought-after property.
Biobased, biodegradable plastics
This group includes starch blends made of thermo-plastically modified starch and other biodegradable polymers as well as polyesters such as polylactic acid (PLA) or polyhydroxyalkanoate (PHA). Unlike cellulose materials (regenerate-cellulose or cellulose-acetate), they have been available on an industrial scale only for the past few years. So far, they have primarily been used for short-lived products such as packaging1 , yet this large innovative area of the plastics industry continues to grow due to the introduction of new biobased monomers such as succinic acid, butanediol, propane diol, or fatty acid derivatives.
Several materials in this group, primarily PLA, are striking a new path – away from biodegradation and towards endof-life solutions such as recycling. The renewable basis of these materials is now at the focus of attention and technical development. Pilot projects aim to establish recycling processes and streams.
This dynamic development proves that bioplastics have the potential to shape the plastics industry, and to produce new innovative and competitive materials. Biodegradable, fossil-based plastics
They are a comparatively small group and are mainly used in combination with starch or other bioplastics because they improve the application-specific performance of the latter by their biodegradability and mechanical properties.
These biodegradable plastics are currently still made in petrochemical production processes. However, partially biobased versions of these materials are already being developed and will be available in the near future.
Source: Fact Sheets, European Bioplastics ,european-bioplastics.org