Solvents-based Green Recycling Process of Polystyrene and Associated Copolymers

J-M. Pin
Polystyvert Inc.,

Keywords: polystyrene recycling, green process, solvent-base recycling, styrenic polymer recycling, flame retardants decontaminantion


Among recycling processes, solvent-based methods present the best balance between quality of the recycled resin, cost, and carbon footprint. Polystyrene (PS) and associated styrenic copolymers such as HIPS, SAN and ABS are particularly suitable for this method. Both post-industrial and post-consumer feedstocks can be treated. Polystyvert patented process consist in the polymer dissolution into an essential oil and a deep purification of the solution. Then, a selective precipitation of the polymer is achieved by addition of a non-solvent. After a devolatilization step, the extruded recycled pellets are pure at 99+ % and therefore, they can be used in the same way as virgin PS. This technology is very flexible in handling a wide variety of contaminants. As an example, Polystyvert process is able to remove banished flame retardants such as Hexabromocyclododecane (HBCD); but in the meantime, can keep, or remove, polymeric flame retardants (PFR). It can be tailored depending on the customer needs. Herein, Polystyvert process allows a circular economy around styrene monomer that comply with the most recent regulations that impose a minimal quantity of recycled plastic in the designed formulations.