Curing Behavior of Reprocessable Epoxy Vitrimers: Thermal Analysis and Kinetics Modeling

Vitrimers are a class of polymers that combine the chemical and mechanical properties of traditional thermosets with the reshaping and reprocessing features of thermoplastics. Their reshaping ability is given by the presence of reversible bonds within their structure. While the nature of bonds that can ensure a dynamic behavior to the crosslinked network is well established, the challenge remains open to assess and control the reactivity of the system to rationally develop materials with desirable features in terms of processability and recyclability. In this work, a "free-model" analysis of the curing reaction of an epoxy/anhydride resin in presence of zinc acetylacetonate as catalyst for both the curing reaction and transesterification is performed. Isothermal and non-isothermal tests are conducted, and the data obtained are analyzed by means of isoconversional methods. The goal is to get an in-depth insight into the reaction mechanism and the structure deriving from the crosslinked network formation, which can ultimately determine the material properties and eventually its actual reprocessability.