Process for Depolymerizing Recycled Polystyrenes

­Executive Summary

Each year, billions of lbs of polystyrene and styrene copolymers are discarded as waste and very little is recycled. While some technologies have attempted pyrolysis in fluidized bed reactors or solvent processes to convert the polystyrene back to monomer, high costs, long process times and a myriad of reaction products have limited their commercial success. MSU researchers have recently developed a new technology for chemical recycling of polystyrenes that is fast and provides and economical route to monomer recovery.


Description of Technology

This invention is a novel process that involves melt processing of polystyrenes in the presence of selected inexpensive and non toxic catalysts. High yield to monomer is obtained in less than 45 minutes process time.



  • Rapid degradation back to monomer (85% yield)
  • Low gas production
  • Enables recycling of waste polystyrene foam, packaging, cups, plates, containers
  • Can be used for styrene containing copolymers
  • Economical process



  • Recycling polystyrene waste


Patent Status

Patent pending


Licensing Rights

Full licensing rights available



Dr. Muhammad Rabnawaz, Dr. Ajmir Khan, Vikash Kumar




Patent Information:

For Information, Contact:

Jon Debling
Technology Manager
Michigan State University