Structure and Dynamics of Associative Exchange Dynamic Polymer Networks

Introducing dynamic covalent bonds can breathe life into polymers by endowing recyclability and tunability to materials, but the characteristic structure and dynamics of associative exchange dynamic polymer networks are yet to be understood. In this study, we present a model to analyze the structure of associative intermediates and the kinetic process of associative exchange. The relationship between the reaction equilibrium constant and the plateau modulus of the associative exchange dynamic polymer networks is established. The model was validated by vinylogous urethane model vitrimers (BPOVU) with different stoichiometric ratios at various temperatures in the equilibrium state. Meanwhile, the thermodynamics and kinetics of BPOVU vitrimers were further analyzed. The model could provide a fundamental understanding of the associative exchange reaction and help direct promising emerging polymer designs and applications.