Eco-friendly, mechanically robust, weather-resistant and rapidly cured polyurea elastomer synthesized by vat photopolymerization 3D printing

• An eco-friendly VP polyurea elastomer was prepared without diluent and solution; • The synthesis rate and viscosity of polyurea prepolymer were reduced; • Explored how acrylate structure affects the mechanical and self-healing properties; • The weather resistance of VP polyurea elastomers has been comprehensively studied. Vat photopolymerization (VP) 3D printing is increasingly employed for efficient elastomer production. However, the printed elastomers often exhibit unsatisfactory mechanical properties, and the process involves harmful volatile substances. Polyurea elastomers, which have a fast reaction rate and high viscosity during synthesis, pose challenges for solvent-free or diluent-free VP 3D printing. This study developed an eco-friendly, mechanically robust and rapidly cured polyurea elastomer by VP 3D printing. The synthesis rate and viscosity of polyurea prepolymer were reduced by controlling the reaction time and stirring speed for reactions without solvent and diluent. Novel urea-acryl resins were designed by employing two acrylic monomers. The mechanical properties of the UV-cured polyurea elastomer were further enhanced through graphene incorporation. The polyurea/graphene nanocomposite at an optimal graphene loading of 0.10 wt% exhibited tensile strength of 12.9 MPa, and elongation at break of 399.2 %. These values correspond to increments of 76.7 % and 66.8 %, respectively, over the neat DLP polyurea elastomer. Moreover, these photocured elastomers exhibited excellent recyclability and weather resistance. The innovative synthesis strategy offers a solution to the mechanical limitations of photocured resins while minimizing environmental impact.