Process to Upcycle Mixed Polyolefins

Executive Summary

Polyolefins are used in a myriad of applications including packaging. Increasingly, there is a growing need for identifying ways of recycling mixed polyolefins that appear in municipal waste streams as the polyolefins are not compostable or biodegradable. While methods such as pyrolysis have been used to transform the plastic mixtures into gases, oils and waxes, a lower carbon footprint approach would be to recycle the plastics directly into other useful products. Researchers at Michigan State University have recently developed a new process for recycling and “upcycling” mixtures of polyolefins into new materials. The process uses additives and can be employed in existing processing facilities.

Description of the Technology

The technology involves processing the mixture of plastics in standard piece of equipment such as an extruder. The polymer mixture melt flow index is adjusted with suitable flow modifiers such as waxes or polymers. A model equation is used to determine the proper amount of flow modifier to add for each polymer. During processing, a compatibilizer is added to upcycle the material into a new product. Experiments have been done with virgin and municipal waste mixtures of HDPE, LDPE, LLDPE and PP using compatibilizers that include styrene block copolymer, maleated polypropylene or reactive compatibilizers. Mechanical tests such as tensile strength and modulus, energy and elongation at break were performed as well as thermal tests TGA and DSC. Depending on the compatibilizer, the mechanical properties of the upscaled product matched the starting HDPE.

 

Benefits

  • Allows upscaling of mixtures of waste polyolefins
  • Avoids pyrolysis as an end of life solution
  • Can use existing processing equipment such as extruders
  • Variety of flow modifiers and compatibilizers can be used

 

Applications

  • Plastics recycling
  • Packaging

 

Patent Status

Patent pending

 

Licensing Rights

Full licensing rights available

 

References

"Virgin-like High-Density Polyethylene from Recycled Mixed Polyolefins", ACS Appl. Polym. Mater. 2023

"Diverting Mixed Polyolefins from Municipal Solid Waste to Feedstocks for Automotive and Construction Applications", Wiley, 2024, Chapter 24

"Challenges in the mechanical recycling and upcycling of mixed postconsumer recovered plastics (PCR): A review", Current Research in Green and Sustainable Chemistry, 2024

 

Inventors

Dr. Muhammad Rabnawaz, Dr. Laurent Matuana, Dr. Tanyaradzwa Muzata

 

TECH ID

TEC2024-0049

Patent Information:

For Information, Contact:

Jon Debling
Technology Manager
Michigan State University
deblingj@msu.edu
Keywords: