Hydroaminoalkylation and Zinc Cross-linking: A Pathway to Recyclable Polybutadiene Materials

Abstract The catalytic hydroaminoalkylation of 1,2-polybutadiene (PBD) in postpolymerization modification has been employed to introduce amine functionalities into PBD50, a commercial polybutadiene containing ∼70 wt % 1,2-vinyl units. This amine introduction significantly enhances the bulk properties of PBD, including increased glass transition temperature, improved viscoelastic behavior, and greater resistance to flow. In this study, we present a novel approach for cross-linking aminated PBD, where the pendant amine groups coordinate to zinc centers, forming N–Zn bonds that link the polymer chains. This chain extension strategy yields materials with higher glass transition temperatures, increased zero-shear viscosity, and more solid-like viscoelastic behavior, reaching values comparable to those obtained with significantly higher amine loadings. Notably, the cross-linked PBD materials exhibit exceptional recyclability, as simple acid treatment effectively removes the cross-linking, restoring the original aminated PBD. This work demonstrates a sustainable and efficient proof-of-concept strategy for developing recyclable PBD-based materials, highlighting the potential of zinc-mediated chain extension as a general approach for designing dynamic and reprocessable polymers.