Polystyrene (PS) is an important element of the global conversation about plastics, particularly as the industry works to move away from the linear plastic economy—and the mindset of take, make, use, and dispose—toward a more circular approach to protect the environment and save valuable resources.
Polystyrene is a highly versatile plastic used in a variety of consumer products. However, negative public discourse focuses on single-use plastics, which represent a very small percentage of its use. As a result, we’ve seen companies shift toward removing polystyrene from packaging. At Trinseo, however, we believe PS is the best material for packaging.
The unique properties of PS are challenging to find in the same combinations in other materials. PS is easily processed, clean, hygienic, lightweight, economical, recyclable, and safe. Given the many benefits of PS, and the lack of a more effective alternative, we must work together to truly unlock the circularity of polystyrene.
Polystyrene has the potential to become infinitely recyclable. The material’s simple chemistry makes it suitable for chemical recycling, as the polymer can be converted back to its monomer state through a process called depolymerisation. The necessary temperature for PS depolymerisation is significantly lower than other polymers, thus requiring less energy. Additionally, the depolymerisation of polystyrene occurs at a very good yield of 65 percent, which means that 100 metric tons of PS can be converted to 65 metric tons of monomer styrene.
PS also has a low migration coefficient, which makes it more difficult for contaminants to diffuse in or out of materials—making it the best candidate for food applications. Not only does PS help ensure food is delivered safely from farm to table, it also helps preserves food freshness for longer. As consumer grocery shopping habits continue to shift in response to the COVID-19 crisis—less frequent trips, more stockpiling, and more online food deliveries—PS will play an essential role in maintaining the safety and integrity of our food.
Unlocking the circularity of polystyrene requires the entire styrenics value chain to join forces. And it will take a lot of awareness and coordination—right now, PS packaging accounts for roughly 750,000 tons of household waste in Europe, but only 150,000 tons are used for recycling.
At Trinseo, we’re collaborating through a number of initiatives, including Styrenics Circular Solutions, an industry wide initiative designed to accelerate the transformation of the industry.
There are three key pillars to the SCS strategy:
- Developing and scaling up innovative technologies to recycle styrenics back into high-quality applications
- Engaging with waste collection and sorting partners to increase the quality and quantity of waste stream output for high-tech recycling
- Using advocacy and communications to raise visibility around styrenics and to highlight the positive qualities of PS
I look forward to sharing more on Trinseo’s collaborative efforts around polystyrene. The future is bright, especially if we continue to collaborate as an industry and along the value chain to innovate and educate.