Key topic: Chemical recycling

Chemical recycling is a key topic of the circular economy, i. e. the goal of conserving raw materials and increasing resource-efficiency through material reuse. It is typically used to recycle certain polymers (plastics). 

The processes applied include solvolysis or depolymerization, which is a key area of expertise at Fraunhofer ICT. In this process, solvents are used to break down polyaddition and polycondensation polymers into monomers or oligomers.

Chemical recycling offers particular advantages in the processing of heterogeneous plastic waste. Hazardous substances remain intact during the process and can be separated from the recyclate, for example by filtration.

Materials suitable for recycling via solvolysis include:

• PET (polyethylene terephthalate, commonly used in packaging and textiles)
• PU (polyurethane, from mattresses, car and airplane seats or building insulation)
• PC (polycarbonate, for example from car headlights, electronic devices, spectacle lenses)
• PLA (polylactic acid, for example from packaging applications)

The top left image shows the chemical recycling of PET in four steps. The end product is a yarn that can be processed for example into roof underlays, or into geotextiles used in dikes for coastal protection, among other applications.

The polyolefin material group, which includes PP (polypropylene) and PE (polyethylene), is also suitable for chemical recycling. However, Fraunhofer ICT also carries out pyrolysis, in cooperation with other groups and institutes.

In the field of chemical recycling, Fraunhofer ICT’s core expertise is solvolysis. Mechanical and physical recycling processes are also under research, in cooperation with other groups and institutes.