Polyurethane Acrylate Covalent Adaptable Networks\nBased on the Autocatalytic Effect of Palm Oil-Based Diol

Polyurethane acrylate (PUA) is a\ntype of photocurable material\nwith high curing efficiency, excellent mechanical properties, and\ngood chemical resistance. However, the synthesis of PUA inevitably\ninvolves the use of toxic catalysts, such as dibutyltin dilaurate,\nwhich imposes a certain burden on the environment. Meanwhile, strategies\nto achieve the self-healing ability and reprocessability of PUA have\nattracted considerable attention. In this study, a palm oil-based\nfatty acid diethanolamide (POEA) with a tertiary amide structure was\nused as a diol to synthesize catalyst-free PUA oligomers and provide\nan autocatalytic effect for the condensation reaction between isocyanates\nand diols. Furthermore, hydroxyethyl acrylate was selected as a reactive\ndiluent for copolymerizing with PUA oligomers and introducing free\nhydroxyl groups to promote the dynamic exchange reaction of carbamates.\nThe autocatalytic effects on both the synthesis and the dynamic exchange\nreaction of carbamates were revealed by model compounds. The resulting\nnetworks exhibited satisfactory mechanical properties, excellent scratch\nrepair capability, and recyclability. Moreover, the prepared PUA films\nshowed superior corrosion resistance with an inhibition efficiency\nof 99.99%, showing great potential applications as coatings for steel.\nThis work provides a feasible technical strategy for the design and\nsynthesis of catalyst-free PUA covalent adaptable networks derived\nfrom plant oils.