Executive Summary
Polyesters comprise a significant portion of plastics entering landfills. One issue that limits their recycling is 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 suite of 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
Several types of sustainable chain extenders are part of this description. The majority are epoxy functional chain extenders based on proprietary long chain aliphatic functional monomers. The second group are anhydride functional copolymers. The chain extenders have been tested in both PLA and PET. Comparisons have been made to existing leading epoxy functional acrylic chain extenders.
Benefits
• 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
Applications
• Recycling / upscaling of polyesters
• Polyester bottles, containers, packaging
• PLA strength building
Patent Status
Patent pending
Licensing Rights
Full licensing rights available
Inventors
Dr. Muhammad Rabnawaz, Dr. Mohamed Abdelwahab, Dr. Ajmir Khan, Hazem Elkholy
References
"Glycidol-Free Aliphatic Copolymers as Chain Extenders for Polylactic Acid and Their Cost and Carbon Emission Assessments", ACS Sustainable Chemistry and Engineering, 2024
"Superior glycidol-free chain extenders for post-consumer PET bottles and PET thermoform blends", Resources, Conservation and Recycling, 2024
"Food-safe glycidyl-free chain extenders for polylactides", Green Chemistry, 2024
TECH ID
TEC2022-0124, TEC2023-0019, TEC2024-0004