Design of Carboxylic Acid‐Functionalized Poly(Butylene Adipate‐<i>co</i>‐Terephthalate) for Recyclable and Biodegradable Zero‐Waste Paper Packaging

Abstract Demand for water‐ and oil‐repellent‐coated paper as an alternative to plastics is growing, but the challenge is that coated paper lacks concurrent recyclability and biodegradability. Reported herein is a novel carboxylic acid‐functionalized poly(butylene adipate‐ co ‐terephthalate) (CPBAT) copolymer investigated for recyclable and repulpable water‐borne paper coatings. The CPBAT synthesized here is characterized by spectroscopic methods. Paper coated with waterborne CPBAT exhibited excellent water, oil, moisture, and gas barrier properties suitable for packaging applications. The recyclability and repulpability of the CPBAT‐coated paper are successfully validated via certified TAPPI methods. This work demonstrates the first successful preparation of coated paper that is per‐ and polyfluoroalkyl substances (PFAS)‐free, recyclable, and biodegradable, with significant benefits for the environment and human health.