3D printable hybrid acrylate-epoxy dynamic networks

Polymer networks with dynamic bonds, also known as covalent adaptable (CANs) combine the superior mechanical properties and chemical resistance of thermosets ability to be reprocessed, a feat formerly attributed only thermoplastics. Inspired by an evergrowing body research on poly(?-hydroxy ester) networks, polyacrylate/epoxy-acid thermoset was designed, which contains high concentration ?-hydroxy ester bonds that partake in transesterification reactions facilitate repair recycle cured material at feasible temperatures. Firstly, liquid formulations are subjected UV light initiate acrylate homopolymerization obtain intermediate, partially-cured material. A subsequent thermal treatment triggers epoxy-acid reaction, improves helps increase likelihood transesterifications new groups formed. The effect post-treatment choice catalyst viscoelastic stress relaxation behavior these materials is studied. Results show that, reach equilibrium less than 4 h 180 °C during time overall cross-linking density increases further. As catalyst, commonly used zinc acetylacetonate outperforms imidazole-type base. Thanks damaged samples can repaired fully using simple procedures. Recyclability tested grinding pristine re-molding them under pressure temperature. Practically complete recovery confirmed.