MSU Technologies

Sustainable Chain Extenders for Recycling Polyesters

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