Vitrimers are derived from thermosetting polymers and a class of plastics. In order to achieve the dynamic transesterification reaction (TER), all epoxy vitrimer systems described in the literature rely on the addition of significant amounts of catalysts until now. The catalysts used in vitrimers have some drawbacks such as being toxic, poor miscibility with organic compounds and causing corrosion resistance. Therefore, researchers first synthesized hyperbranched epoxy (HBE) prepolymers and then reacted with succinic anhydride to provide a catalyst-free epoxy vitrimer system. It was revealed that TER processes and curing were achieved by free hydroxyl groups in HBE. Moreover, it was also proved that at elevated temperatures (>120 °C), the TER is activated to enable fast stress relaxation of the cross-linked network. Therefore, this system is promising for self-healable and catalyst-free coatings.
Journal reference: Macromolecules
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