<br/>Thermoset polymers are classified amongst the most challenging materials to recycle due to the permanent crosslinks that increase their strength and stiffness compared to their thermoplastic counterparts. A new class of polymer networks, called vitrimers, presents a promising route to achieve recyclability in thermosets by implementing dynamic covalent bonds within the system. This work shows how coarse-grained molecular dynamics, in conjunction with a Monte Carlo step, can be used as a simulation technique to model the bond exchanges in these networks accurately. The model proposed in this work can accurately describe the dynamic nature of the covalent network while always maintain a constant crosslink density. This framework also shows flexibility in accommodating different rate constants of bond exchange reaction that is consistent with the catalyst effect in the reaction kinetics during experiments. Here we will show how the dynamic and rheological properties of the vitrimer system are deeply affected by the kinetics of the bond exchange reaction, thus allowing for an in-depth study of the bond lifetime and microstructure relaxation time of vitrimers. The results of this work will help establish a linkage between the macroscopic timescales, such as shear deformation timescale, and microstructural rearrangements in vitrimers and help with the rational design of shape-memory and self-healing polymeric materials.

Effect of reaction kinetics on dynamics and rheology of vitrimers

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.