A world without plastics is inconceivable. Dr. Manuel Häußler gives vivid examples of why this is the case at the SOLPACK Forum. “Nobody would like to wash a syringe several times, but as a disposable product, even if it is not so sustainable,” says the chemist. Another example: on average, a car contains 300 to 500 kilograms of plastic. Half of all plastics go into the packaging industry, says Häußler, who works as a scientist at the Max Planck Institute, Center of the Transformation of Chemistry and is the founder of the start-up aevoloop GmbH.
As more and more petroleum-based plastic ends up as waste, the question of sustainable alternatives arises. According to Häußler, only a third of plastic is recycled, while two thirds is incinerated. “Expanding recycling capacities is more difficult than producing new plastics,” he explains.
Mechanical Recycling Reaches its Limits
The established technology for reprocessing plastics is mechanical recycling. In mechanical recycling, plastic waste is melted down and processed into granulate, which in turn is used as a secondary raw material in packaging or other products. This works well in principle, but also encounters obstacles.
This is because the material supplied for mechanical recycling must be sorted by type and as free as possible from contamination or foreign matter. The more both are the case, the better the separation and cleaning processes can ensure a high-quality recyclate. However, according to the expert, there are further difficulties. Material ageing, for example, changes the plastic it contains. In addition, many products made from composite materials cannot be processed using this method alone. This applies, for example, to many food packaging products that contain several layers of plastic. Even PET bottles are only recyclable to a small extent. All new plastics focus on being bio-based or biodegradable. This is not recyclable.
Chemical recycling is “energy-hungry”
Chemical recycling, on the other hand, has a bad reputation, but is actually a “great idea”, says Häußler. This is because plastic is seen as a raw material, but not every plastic is suitable for this process; PE and PP, for example, are not suitable at all. The best-known chemical process at the moment is pyrolysis, in which plastics are converted into pyrolysis oils. “This is a very energy-intensive alternative,” says Häußler.
DNA of the plastics
His proposed solution: “We go into the DNA of the plastics.” His start-up is developing new types of plastic with a holistic sustainability concept. It goes into the smallest unit of plastics, the monomers.
The expert reports on a new composition of polymers that can be broken down into monomers without chemical recycling. This topic is of great importance due to the imminent challenge of using recyclates in plastic packaging, but also in the textile industry. “To solve the problem, we need fully recyclable plastics. The good news is that any plastic can be redesigned at a molecular level.”
To this end, his team is building a new class of sustainable platform chemicals based on long-chain dicarboxylic acids. These molecules are the proposal for the efficient chemical use and recycling of carbon in the future. The approach enables the production of a wide range of chemical products that can be completely recycled back into the original central platform chemical after use. It is crucial that the molecules are easily modifiable, yet chemically robust and exceptionally crystalline, which considerably simplifies their recovery.
Chemical products based on Häußler's platform chemicals are therefore inherently recyclable, opening up recycling opportunities for applications that previously seemed impossible. “In combination with their biodegradability, we believe that long-chain dicarboxylic acids are the ideal platform for a sustainable chemical industry.”
