Materials supplier Trinseo is out to improve polystyrene's public image.
Many people do not realize just how much PS is used, said Julien Renvoise, recycling and marketing manager for Europe, the Middle East and Africa at Trinseo. To begin with, polystyrene is one of the "best" materials available for food packaging.
"It's been used for the past 70-80 years." And while it is, for the most part associated by many with single-use and disposable applications, it has found much wider application in other sectors as well.
As he told Sustainable Plastics during a recent telephone interview, PS is also the material of choice for refrigerator liners and, when foamed, serves as the core material in insulation panels. This ubiquitous use of PS means that it is imperative to seek the best disposal solution for the material at the end of life.
"Of course, we need to consume less, and to generate less waste. And for the waste that we have, we think that recycling is the best way to dispose of these materials," Renvoise said. Yet while mechanical recycling is an excellent solution in many cases, the "complex, multi-layered structure of much packaging, that is moreover often highly contaminated," presents a challenge.
"Moreover, we see a big deterioration in properties with mechanical recycling," he said. This is the reason why Trinseo is looking at other solutions.
The company has been a major driver behind the development of chemical recycling processes for PS — the "holy grail to address the challenge of plastic waste," Renvoise said.
"Chemical recycling offers a broader scope, but it costs more energy. There is an urgent need for a parallel development: In other words, not one or the other, but both kinds of recycling are needed if we are to reach the recycling targets of the European Commission," he explained.
And PS is a polymer with unique circularity potential, as it is most easily reversed into its original monomer, at high yield, with the help of the latest chemical recycling technologies. The liquid state of its monomer enables easy purification and the recycled monomer is identical to the virgin monomer. It can thus be processed into virgin-like styrenic polymers, suitable for all applications, including food contact. Also, from there it can be continuously recycled, over and over again.