Thermomechanical Characterization of an Unsaturated Polyester Vitrimer Synthesized Using a Titanium Transesterification Catalyst

Unsaturated polyester resins (UPRs) are widely applied thermosets characterized by good thermo-mechanical properties and excellent chemical resistivity. However, the non-reprocessability of UPRs once cured, together with the increasing amount of their waste, has recently urged research and industries to develop more sustainable substituents. In this work, an unsaturated polyester vitrimer was synthesized and characterized by exploiting titanium (IV) butoxide as the transesterification catalyst. This simple approach demonstrated how the design of a covalent adaptable network could solve the issues related to reprocessability, self-healing, and the recyclability of unsaturated polyester thermosets. Here, an intramolecular transesterification exchange was exploited to confer reparability, reshaping, and thermoforming abilities to commercial polyester. Furthermore, the mechanical properties, the glass transition, and the chemical stability of the polyester resin were preserved despite the conversion of the thermoset matrix into a vitrimeric network.