Climate change, environmental pollution, population growth and resource dependency trigger the ecological and economical necessity to transition from a linear to a circular economy. Polymers generally contribute to resource savings during their whole life cycle: their production is energy-efficient, they are lightweight yet durable, and their properties can be optimised to fit the special requirements of their applications. On the other hand, particularly their durability may also pose a problem, if the recycling of the polymers is not an integral part of the overall concept.

polystyrene cups
Joghurt cups made of polystyrene during and after use.

Plastics can be recycled in various ways. The well-known and widely-practiced conventional mechanical recycling is quite limited due to high requirements for the feedstock and poor quality of the recyclate, which in many cases is only seen as second-grade material. Therefore plastic waste is often incinerated (thermally recovered) or even landfilled.¹

The revival of concepts for chemical recycling is a huge step forward, because it avoids incineration to a great extent, especially for plastic waste that cannot be mechanically recycled (anymore). Plastic waste is regarded as valuable raw material again, and the bound carbon can be kept in the loop. CO2 emissions thus are minimised, and, on the long run, losses might be compensated with utilisation of biomass.

¹A food contact quality mechanical recycling process for polystyrene is currently under development.