Circular Plastics for the Modern Economy
In Support of the European Commission’s anticipated “Plastics Strategy”
By 2015, humans generated 8.3 billion metric tons of plastics, 6.3 billion tons of which had already become waste, according to scientists at the University of Georgia (link to study).
Plastic is everywhere: in our clothes, vehicles, electronic devices, building materials, and, as recently discovered, in our food and drinking water.
In response, the European Commission’s Plastics Strategy plans to address three interrelated issues: high dependence on virgin fossil feedstock, low rate of recycling and reuse of plastics, and significant leakage of plastics into the environment.
In support of these efforts, the European Commission-funded project PolyCE will advance recycling and recovery solutions of plastics found in electronic devices (e-plastics) in Europe.
What are E-Plastics?
When technology reaches the end of its useful life, some of its components are recycled, reused, or refurbished. Others, like scrap electronic plastic waste, often become one of the most challenging types of materials to manage in the recycling industry.
The general composition of the plastic fraction itself is depicted in the figure below. The main constituents of the plastic-fraction of the Waste Electric and Electronic Equipment (WEEE) are ABS, high impact polystyrene (HIPS), polycarbonate (PC), PC/ABS and polypropylene (PP).
Impact on Health and the Environment
When improperly treated, e-plastics can be hazardous and can have negative effects on human health and the environment. This is due to the compounds used during manufacturing, most notably brominated flame retardants (BFRs). Disintegration of foam products, volatilization by e.g. incineration at high temperatures with insufficient gas purification, or simply leaching of the BFR from products during use at disposal sites during combustion or at landfills — these are routes in which the BFRs can enter the environment. As BFRs are more lipophilic rather than water soluble, these substances tend to accumulate in sediments, sewage slugs, or particles, making transportation and entering into the biotope of animals a reasonable risk that should be further researched. There is evidence that BFRs are linked to endocrine and neurological damage in both animals and humans, causing infertility and thyroid disorders in adults, and impaired mental/physical development in children (link to study).
In addition, when BFRs are discarded into the environment, they bioaccumulate (link to study). This means that they do not deteriorate or dissipate over time. Instead, the pollution builds. For this reason, BFR-containing plastics should be identified and isolated from the waste streams to be dealt with accordingly.
Recycling e-plastics can therefore be difficult. Some plastics can be melted down and used to manufacture new items, but most plastics are not recycled in this way. Instead, many plastic recycling facilities prepare the plastic to be repurposed, or “down-cycled.” E-plastics are more challenging to recycle because of the brominated flame retardants that can exist in these waste fractions. The recycling of the BFR-containing e-plastics is somewhat hampered by the ban on certain polybrominated diphenyl ethers (PBDEs) like penta-BDE, octa-BDE, and deca-BDE (link to study). Though these are no longer used in production, a significant amount of the e-plastics in use still contain these BFRs. Nowadays converters/recyclers separate these contaminated FR plastics from the recycling stream to avoid environmental issues, yet as a result they often end up being carried away or incinerated. More research must be done to find suitable ways for extraction and disposing or recycling these banned plastics.
During the next four years, PolyCE will demonstrate the feasibility of reusing high quality post-consumer recycled plastics for the development of new electronic products. This can be done by adding the depleted additives like antioxidants, pigments, and flame retardants, and upgrading the plastics to improved properties. In the latter case, new FR are being developed in collaboration with Tecnalia to provide better alternatives to the brominated FR, while collaborations with Sitraplas focus on upgrading the recyclates by new sorting techniques and recovery of bromine and antimony in flame retardant containing products. In this way, WEEE streams can be purified, leading to better product properties.
In addition, the project will develop a grade system for recycled e-plastics according to their material properties and final application suitability. This is to strengthen the market for recycled plastics through an online platform that integrates the different plastic grades.
To shift towards a circular economy, a systematic transformation is required. While substantially reducing the e-plastics generation and enhancing the use of recycled plastics in new applications, PolyCE will demonstrate the feasibility of circular plastics for the modern economy.