The End of Brittle Materials from Recycling of Mixed Plastics: A Universal Upcycling Solution

At a Glance

Researchers at Colorado State University have developed a second generation of universal dynamic crosslinkers (UDCs) that enable the transformation of incompatible mixed plastic waste into strong, flexible, and reprocessable materials. By creating star-like polymers in situ during a reactive extrusion process in the presence of a small of a UDC, the UDC eliminates the phase separation typically seen in mixed plastic blends. The innovation allows for the creation of new materials from recycling of plastic mixtures with reprocessability and properties that can be adjusted for different applications, from stiff, thermoset-like materials to flexible, thermoplastic-like materials.

Background

Mechanical recycling of mixed plastics typically results in brittle, low-quality materials, a process known as “downcycling,” because different types of plastics do not mix well. While some existing methods address this, they are often tailored to specific plastic combinations, making them impractical for the complex, large-scale waste streams found in post-consumer recycling. This new UDC platform offers a universal dynamic compatibilization solution to this problem, enabling the creation of high-value materials from a wide range of mixed plastics.

Overview

This new UDC platform is based on readily available diazomalonate carbene precursors and dynamic siloxane linkages. The key advancement is the high activation temperature of the diazomalonate moieties (~180°C), which is compatible with the melt-processing temperatures of most common plastics. This allows the UDCs to be used in reactive extrusion, a solvent-free process suitable for large-scale industrial recycling.

The multi-arm structure of the new UDCs is more effective at compatibilizing different plastics than previous linear UDCs. This universal compatibilization strategy has been shown to reduce phase separation in polymer blends. Quantitatively, the new UDCs have been demonstrated to drastically enhance creep resistance by 2-4 orders of magnitude and improve the extensibility of polymer blends by up to 100-fold compared to uncompatibilized blends. By adjusting the number of arms on the UDC and the amount used, the properties of the final material can be tuned to be more like a rigid thermoset or a flexible thermoplastic.

Benefits

Universal Compatibility: Works across diverse polar and non-polar plastics and their mixtures.
High Thermal Stability: Activation temperature supports melt-processing.
Significant Property Enhancement:
- Creep resistance improved by 100x–10,000x.
- Tensile elongation improved by up to 100x.
- Tensile strength increased up to 60%.
Modular and Tunable: Mechanical properties can be customized by adjusting UDC type and loading.
Reprocessable: Maintains performance over multiple processing cycles.
Low Additive Loading: Effective at just 1 wt% in many cases.
Color Stability: Minimal discoloration compared to existing systems.

Applications

Mechanical recycling and upcycling of mixed post-consumer plastics
Compatibilization of commodity plastic blends in packaging
Automotive and consumer goods using recycled plastic composites
Reusable and recyclable wearable materials
Development of new thermoplastic elastomers and thermoset-like materials

Publications

Y. Gao, et al. (2025), “Topological universal dynamic compatibilization enhances recycling of mixed plastics.” Nature Sustainability. https://doi.org/10.1038/s41893-025-01688-5

Last Updated: August 2026

Opportunity

Available for Non-Exclusive Licensing
TRL: 4

IP Status

US 19/702,682

Inventors

Eugene Chen
Yunpeng Gao
Xavier Westworth

Reference Number

2025-097

Licensing Manager

Aly Hoeher
Aly.Hoeher@colostate.edu
970-491-7100