Extrudable vitrimeric elastomer enabled by interfacial stress amplification of multiphase network

JL Chen and SJ Yu and SW Wu and ZH Tang and BC Guo and LQ Zhang, SCIENCE CHINA-MATERIALS, 68, 2032-2043 (2025).

DOI: 10.1007/s40843-025-3337-2

Involving dynamic covalent bonds (DCBs) in polymers offers a promising method for the recycling of traditional thermoset elastomers. However, the continuous reprocessing of DCB-based elastomer, especially DCB cross-linked rubber, faces daunting challenges. To address this issue, multiphase design with heterogeneous cross-linking has been proposed as an ingenious and effective approach and has achieved surprising success. Herein, a novel constructing avenue for DCB-based multiphase rubber is presented by virtue of the in-situ modification and the resulting interfacial exchange reaction. The prepared sample combined a high gel ratio (>95%), mechanical toughness, excellent elasticity and significantly improved extruded reprocessability. Further, the chain segment behavior and local stress evolution during tensile or shear deformation of vitrimeric elastomer with multiphase network at the molecular level and their effects on the macroscopic properties of the material are systematically investigated by coarse-grained molecular dynamics (CGMD) simulation to reveal the unclarified intrinsic mechanism including mechanical enhancement and the acceleration of DCB exchange from the amplified interface stress in multiphase network. We envisage that the revealed related mechanisms of heterogeneous networks in force fields will provide new insights into the study of such networks, thus facilitating the development of the heterogeneous vitrimeric elastomer from concept to practical applications.

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