Recyclable and Reprocessable Cross‐Linked EPDM Rubber by Constructing Ionic Cross‐Linked Networks via Bio‐Based Zinc Phytate

ABSTRACT Endowing rubber with recyclability represents a critical advance for energy conservation. Herein, we report a sustainable and commercially feasible strategy for developing recyclable ethylene‐propylene‐diene monomer (EPDM) rubber via exchangeable ionic cross‐links. Maleic anhydride (MAH) was grafted onto EPDM to produce EPDM‐g‐MAH, introducing reactive carboxyl moieties; subsequently, bio‐derived zinc phytate (ZnPA) was employed as a green cross‐linker to form reversible ionic bonds. After the first recycling cycle, the EPDM‐g‐MAH@ZnPA rubber retained 96% of its tensile strength and more than 99% of its elongation at break. Even after three recycling cycles, the tensile strength remained at 82%. To balance mechanical performance and recyclability, zinc dimethacrylate (ZDMA) was incorporated to construct a dual dynamic cross‐linking network. The EPDM‐g‐MAH@ZnPA/ZDMA‐50 composite achieved a tensile strength of 5.86 MPa and a tear strength of 34.2 N/mm. After recycling, it retained 96.8% of its tensile strength and 86% of its elongation at break, exhibiting excellent structural stability during repeated processing. This work presents a bio‐inspired, sustainable strategy for designing high‐performance recyclable rubber materials by integrating bio‐based cross‐linkers into dynamic network architectures.