Development of Marine‐Degradable Poly(Ester Amide)s with Strong, Up‐Scalable, and Up‐Cyclable Performance

Abstract Biodegradable polyesters provide an attractive alternative to non‐degradable plastics but often encounter a tradeoff between biodegradability and mechanical properties because esters are rotational and lack hydrogen bonds. Conversely, natural polyamides, i.e., silk exhibit excellent mechanical strength because amides are non‐rotational and form hydrogen bonds. Unlike esters, the nitrogen in amides can enhance microbial biodegradation. However, protein engineering exhibits limited productivity, and artificial polyamides, i.e., nylon remain non‐degradable due to their hydrophobic nature. Herein, a method is proposed for developing poly(ester amide)s (PEA)s, a polyester and polyamide hybrid, to address prevailing production challenges. These materials are synthesized from upcycled monomers in a 10 L reactor and converted into films and yarns. They achieve a tensile strength of 109 MPa and tenacity of 5.0 g de −1 , while withstanding ironing temperatures. They achieve a remarkable 92% marine biodegradability in 12 months, which is rarely attained by current bioplastics, and exhibit low environmental impact in terms of greenhouse gas emissions. While biodegradable polyesters have remained within the performance range of commodity plastics, PEAs fall into the high‐performance category, potentially reaching markets that existing biodegradable plastics have not, such as fishing lines and clothing.