Epoxy Vitrimers: The Effect of Transesterification Reactions on the Network Structure
AbstractVitrimers are covalently crosslinked polymers that behave as conventional thermosets below the glass transition temperature (Tg) but can flow above a particular temperature, Tv > Tg, by bond exchange reactions. In epoxy vitrimers, transesterification reactions are responsible for their behavior at T > Tv that enables flow, thermoforming, recycling, self-healing and stress relaxation. A statistical analysis based on the fragment approach was performed to analyze the evolution of the network structure of epoxy vitrimers during transesterification reactions. An analytical solution was obtained for a formulation based on a diepoxide and a dicarboxylic acid. A numerical solution was derived for the reaction of a diepoxide with a tricarboxylic acid, as an example of the way to apply the model to polyfunctional monomers. As transesterification acts as a disproportionation reaction that converts two linear fragments (monoesters) into a terminal fragment (glycol) and a branching fragment (diester), its effect on network structure is to increase the concentration of crosslinks and pendant chains while leaving a sol fraction. Changes in the network structure of the epoxy vitrimer can take place after their synthesis, during their use at high temperatures, a fact that has to be considered in their technological applications. View Full-Text
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Altuna, F.I.; Hoppe, C.E.; Williams, R.J.J. Epoxy Vitrimers: The Effect of Transesterification Reactions on the Network Structure. Polymers 2018, 10, 43.
Altuna FI, Hoppe CE, Williams RJJ. Epoxy Vitrimers: The Effect of Transesterification Reactions on the Network Structure. Polymers. 2018; 10(1):43.Chicago/Turabian Style
Altuna, Facundo I.; Hoppe, Cristina E.; Williams, Roberto J.J. 2018. "Epoxy Vitrimers: The Effect of Transesterification Reactions on the Network Structure." Polymers 10, no. 1: 43.
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