Looping and gelation kinetics in reversible networks based on furan and maleimide

This work presents a detailed kinetic study on the Diels-alder reaction between furan and maleimide moieties based on variable temperature infrared spectroscopy. BMI–689 was mixed with a multifunctional furan monomer. The furan functionality of the furan-bearing monomers was varied to observe any differences in reaction conversion and the resulting kinetic description of these networks. The endo and exo stereo isomers being formed during the Diels-Alder reaction are considered in this description and have been observed through ex-situ 1 H NMR spectroscopy. The kinetic parameters were further used to predict the required percolation time for each system at any temperature. The activation energy of the forward Diels-Alder reactions were between 46 and 60 kJ mol −1 and backward activation energies between 87 and 119 kJ mol −1 . Only minor differences were found in the final Diels-Alder conversion developments by comparing systems with a varying monomer functionality, implying that the percolation process does not influence the kinetics for these systems. Finally, we shed light on the percolation process and occurrence of looping throughout the reaction of the used bismaleimide and various furan-bearing constituents via coarse-grained molecular dynamics simulations. The results of this study form a basis for understanding the temperature dependent self-healing behavior of such materials, and for defining temperature programs in 3D printing and extrusion applications, where rapid solidification while ensuring reprocessability are the main challenges. • This work investigates the gelation and reaction kinetics of furan-maleimide Diels-Alder systems. • Variable temperature infrared spectroscopy was used to follow the reaction conversion. • Endo-exo adduct contributions could be distinguished with NMR spectroscopy, and deduced from full conversion developments. • The effects of looping in the system are highlighted using coarse-grained simulations. • This study sets a basis for utilizing such systems in extrusion, 3D printing and injection molding processes.