Structural Design of CANs with Fine-Tunable Relaxation Properties: A Theoretical Framework Based on Network Structure and Kinetics Modeling

In this work, wepresent a model capable of reproducing the stressrelaxation dynamics of a wide range of relaxation processes in covalentadaptable networks (CANs) produced by stepwise polymerization. Theproposed model captures the effective elastic response of the materialsubject to an initial stress by analogy with a network decrosslinkingprocess. The combination of a recursive structural model and a kineticmodel for the bond exchange reaction makes it possible to predictthe expected stress relaxation profile in simple and complex systemsdepending on the structure of the network, the rate of bond exchangeof the different components, and the presence of permanent bonds.After the basic features of the model are analyzed, its predictioncapabilities are validated by simulating a number of scenarios takenfrom the literature. The results show that tailoring of the networkarchitecture enables unprecedented flexibility in the design of CAN-basedmaterials.