Influence of high strain rate and catalyst concentration on dynamic impact behavior of vitrimers

Abstract

Abstract Vitrimers are dynamically cross-linked networks with dynamic covalent bonds, possessing attractive mechanical robustness, self-healing, re-processability, recyclability, and shape memory properties. Therefore, vitrimers hold promise for applications including aerospace and transportation, in which cases the structures will inevitably be subjected to dynamic loading. The objective of this study was to characterize the dynamic impact behavior of vitrimers utilizing the Split Hopkinson Pressure Bar (SHPB) experiments. Five kinds of vitrimers containing different concentrations of catalyst Zn(acac)2 of 0.1, 1, 3, 5, and 10 mol% and two strain rates 2000 s-1 and 4000 s-1 are considered. These vitrimers exhibit strain rate dependence, whose yield stress and strain softening effect is enhanced when the strain rate is increased from 2000 s-1 to 4000 s-1. Catalyst concentration significantly affects the dynamic performance, and the vitrimer with 10 mol% catalyst shows the most pronounced strain softening, the highest yield stress, and the best impact energy absorption properties. The results provide fundamental data and strategies for improving the impact resistance of epoxy for engineering applications.