One-Pot Ketone Functionalization of EPDM toward Recyclable and Creep-Resistant Elastomers Cross-Linked with Biobased Amines

Abstract

Introducing dynamic covalent networks into conventional ethylene-propylene-diene monomer (EPDM) rubber offers a promising strategy for developing thermally reprocessable elastomers; however, it requires the introduction of reactive functionalities onto the chemically inert hydrocarbon backbone. Herein, ketone-functionalized EPDM (K-EPDM) was prepared through a one-pot strategy combining epoxidation and oxidative cleavage of the double bonds in EPDM. Then, K-EPDM was cross-linked with biobased amines to construct imine-cross-linked elastomers. Exchangeable imine linkages served as the primary reversible cross-linking motifs, whereas a small fraction of irreversible epoxy-amine cross-links derived from residual epoxy groups provided additional constraints for improving dimensional stability. The resulting elastomers exhibited tunable mechanical properties, good elastic recovery, thermally activated stress relaxation, reduced creep deformation, thermally induced shape adaptability, and high retention of mechanical performance after repeated thermal reprocessing. Hence, this work provides a simple and promising strategy to synthesize ketone-functionalized rubber, which can be further cross-linked with biobased amines to obtain dynamically cross-linked EPDM elastomers with thermal reprocessability and improved creep resistance.