OUR FOUR FOCUS AREAS: 

1. Designing for better recyclability
2. Mechanical recycling
3. Chemical recycling
4. Enzymatic recycling

1. Designing for better recyclability

Many challenges in recycling stem from products and polymers that are badly suited for recyclability. At the Department of Chemistry and Bioscience, we are researching how food packaging products and polymers can be re-designed for better recycling to provide better feedstock for a circular economy.

2. Mechanical recycling

Mechanical recycling of plastic means physically processing and reusing plastic materials through grinding, pelleting, and moulding without changing their chemical structure. It is thereby the most energy and resource-efficient mode of recycling. However, as the chemistry and properties of plastics change over time and in use, it is critical to understand how plastic changes and its properties before using it for making new products.

At the Department of Material and Production, we develop advanced spectrometry techniques and other physical testing approaches to better predict how plastics change and develop quick and efficient quality control methods for the use of recycled plastics in production. By gaining insights into the behaviour and performance of these materials, we can optimize the recycling process and ensure the production of high-quality recycled products.

3. Chemical recycling

Unlike mechanical recycling, which has limitations in processing certain types of plastic waste, chemical recycling utilizes pressure, temperature, and solvents to break down plastics into oils that can be used to produce new plastic materials.

This approach is particularly beneficial for mixed plastic waste, such as food packaging, which cannot be effectively recycled through traditional methods.

In the Department of Chemical Engineering at AAU, we research technologies like pyrolysis and solvolysis to convert these challenging waste fractions into valuable resources. Pyrolysis involves heating the plastic waste to create oils that can be used to produce new plastic, while solvolysis utilizes solvents at high temperatures and pressures to decompose thermoset materials and recover fibres for reuse.

Specifically, we are researching chemical recycling of mixed plastic waste (Pyrogreen Project), textiles, composites, and electronics.

4. Enzymatic recycling

The use of enzymes allows – like chemical recycling – to decompose plastic waste into valuable resources that can be used to produce new polymers.

Enzymatic processes are not as fast as pure chemical treatment, but they have the advantage of requiring less energy, and no special facilities, and they can work on polymer mixtures such as composite materials to regain pure building blocks without extensive separation processes. However, the range of available enzymes for industrial-scale application is currently still limited to PETase, an enzyme for the depolymerization of PET.

At the Department of Material and Production, we are working on broadening the range of processes for industrial use of enzymatic recycling. Specifically, we are developing enzymes for the depolymerisation of polycarbonate, using both classical approaches and the innovative methods of De novo enzyme design.