Advancing Renewable Materials via Microalgae-Derived Thermoplastic Polyester Polyurethanes

To remediate the growing global impacts of plastic waste, it is imperative to design sustainable materials that can be used as replacements for current nonrenewable and nonbiodegradable commercial products. Addressing this issue requires careful selection of both material class and renewable feedstock source to maximize the sustainability of production processes and end-of-life outcomes. This work describes the use of microalgae as a renewable feedstock for preparation of thermoplastic polyester polyurethane (TPU) materials. The sustainable and robust photosynthetic capacity of microalgae paired with cleavable bonds within the polyester TPU backbone result in a material that promotes efficient resource use and reduced ecological impact at the end of its life cycle. High-purity TPU monomers derived from Nannochloropsis salina oil were used to synthesize the first 100% microalgae-sourced TPU material from azelaic acid (AzA), 1,7-heptamethylene diisocyanate (7-HDI), and 1,9-nonanediol (NDO). For comparison, a TPU containing 75% microalgae-content was also prepared utilizing industry-standard 1,3-propanediol (PDO). Thermal and mechanical characterization was used to analyze the structure–function properties of the TPUs and assess potential industrial applications. Overall, this work seeks to offer a viable alternative to conventional plastics, supporting the global transition toward sustainable plastic usage.