Sustainable Chain Extenders for Recycling Polyesters

Executive Summary

Polyesters comprise a significant portion of plastics entering landfills. One issue that limits their recycling is natural degradation during melt processing which lowers their molecular weight and melt viscosity. Reactive chain extenders are often used in this case to build back the molecular weight of the polyester during reprocessing. However, some currently used chain extenders contain hazardous ingredients, either present as residuals or that form during decomposition during use. This can limit their use in certain markets including food contact applications. MSU researchers have developed a new family of epoxy functional chain extenders that have excellent thermal stability and do not contain undesirable monomers. This allows their use in a broad range of applications from recycling to synthesis of virgin polymers.  


Description of Technology

This invention is a family of epoxy functional chain extenders based on proprietary long chain aliphatic functional monomers. The chain extenders have been tested principally in PLA with ongoing experiments focused on PET. Comparisons have been made to existing leading epoxy functional acrylic chain extenders.



    Do not contain styrene or glycidyl methacrylate monomers

    Excellent thermal stability as good or better than leading epoxy functional acrylic chain extenders

    Improved tensile modulus, elongation at break and impact strength of PLA compared to leading epoxy functional acrylic chain extenders

    Can be used with a range of polyesters including PET, PBT, PLA



    Recycling / upscaling of polyesters

    Polyester bottles, containers, packaging

    PLA strength building


Patent Status

Patent pending


Licensing Rights

Full licensing rights available



Dr. Muhammad Rabnawaz, Dr. Mohamed Abdelwahab, Dr. Ajmir Khan, Hazem Elkholy



TEC2022-0124, TEC2023-0019

Patent Information:

For Information, Contact:

Jon Debling
Technology Manager
Michigan State University