Using Zn²⁺ Ionomer To Catalyze Transesterification Reaction in Epoxy Vitrimer

Vitrimers are fascinating thermoset polymers to the industry since they can be recycled and reprocessed without compromising their mechanical strength and solvent resistance. Particularly, transesterification reaction in the epoxy resin (ER) vitrimers usually requires the incorporation of a catalyst, whereas most reports only focused on investigating the catalytic effect of small molecules, such as zinc acetate (Zn­(OAc)2) and triazabicyclodecene (TBD). In this work, a polymer catalyst, poly­(acrylonitrile-co-zinc methacrylate) (Zn-PAM), was synthesized by the random copolymerization of zinc methacrylate and acrylonitrile, where the transesterification catalysis efficiency of Zn-PAM was systematically investigated and compared to that of Zn­(OAc)2 and TBD by temperature-dependent stress relaxation experiments. It was revealed that Zn-PAM has a higher catalysis efficiency than Zn­(OAc)2 and TBD under the same loading between Zn2+ and TBD. Besides, only a tiny amount of polymer catalyst is needed to efficiently catalyze the transesterification reaction while in the meantime enhance the mechanical properties of ER