From Low-Cost Industrial Byproducts to High-Performance Flexible Films and Water-Based Hydrophobic Coatings via Green Processes

The conversion of abundant industrial olefinic byproducts or wastes into high-value functional polymeric materials is critical for sustainable resource utilization. However, their further application is largely hindered by low molar masses and extremely poor mechanical properties. Herein, we report a green strategy to convert mixed olefin-MAH copolymers, synthesized from petrochemical and coal chemical byproducts, into robust films and durable hydrophobic coatings. By taking poly(propylene glycol) (PPG) as the chain extender and precisely controlling the molar mass, chain flexibility was largely enhanced. Subsequent ammoniation facilitated water solubility, allowing film formation via aqueous processing. Thermal treatment induced cross-linking and imidization, yielding flexible films with exceptional mechanical properties, with optimal tensile strength ranging from 14 to 41 MPa and elongation at break from 4.5% to 370%, along with superior thermal stability and water resistance. Furthermore, the method was also successfully applied to create waterborne coatings on different substrates (wood and cotton), displaying superior hydrophobicity, wear resistance, and durability. Our work established a green and scalable solution for upcycling low-cost mixed olefins into high-performance materials through eco-friendly processes, contributing to more sustainable manufacturing practices.