Photo-photo dual-cured vitrimer based on cardanol and glycerol derivatives

Abstract

This work presents the first photo-photo dual-curable vitrimer resin, representing a difference from previously reported dual-curable vitrimer resins that relied on photo-thermal curing of acrylate-epoxy formulations. The design, synthesis and characterization of a vitrimer based on cardanol and glycerol derivatives were performed. A life cycle assessment has shown that the fossil carbon footprint of epoxy cardanol resin NC-514S is 1.6 times lower than that of bisphenol A-based epoxy resins, confirming its suitability as a bio-based alternative to petroleum-based epoxy resin. Dual-curable resin compositions containing epoxidized cardanol resin NC-514S, different glycerol-based acrylates, and thiol pentaerythritol tetrakis(3-mercaptopropionate) were formulated to ensure both simultaneous cationic and radical photopolymerization. Photocuring kinetics studies revealed an optimal resin with viscosity and rheological characteristics close to those of common commercial 3D printing resins. The optimized resin containing 20 wt% of epoxidized cardanol resin NC-514S, 20 wt% of glycerol 1,3-diglycerolate diacrylate, 40 wt% of 2-hydroxy-3-phenoxypropyl acrylate, and 20 wt% of pentaerythritol tetrakis(3-mercaptopropionate demonstrated vitrimeric properties, including shape-memory recovery within 120 s above the topology freezing temperature and glass transition temperature, self-welding with a 76% increase in tensile strength and a 125% increase in Young's modulus after self-welding, and reprocessability with mechanical properties retained after 3 reprocessing cycles. These results demonstrate that synthesized vitrimer is a promising material for reconfigurable or reusable packaging and packaging component applications, as well as various other adaptive structures and devices, while supporting sustainable use in reprocessable materials and circular economy applications.