State-of-the-art UV-assisted 3D printing via a rapid syringe-extrusion approach for photoactive vegetable oil acrylates produced in one-step synthesis

Abstract

The progress of additive manufacturing (3D printing) in modern engineering and manufacturing solutions aligns well with the global movement toward renewable materials and sustainable development. In this article, we report the first-time successful 3D printing of photoactive vegetable oil acrylates via an extrusion approach using a syringe-based 3D printer with integrated UV LEDs and a 0.8 mm print nozzle. Using this approach, exact and small amounts of material can be used and combined with design freedom, fewer processing steps, and a low-cost system. The 3D printing resins were obtained through optimized one-step acrylation, which yields the desired reactivity and suitable viscosity. Rapeseed, linseed, and grapeseed oils were selected based on their fatty acid molecular composition and crop cultivation potential to tune and optimize resin performance. NMR spectra showed that the acrylation yield decreased with the increase of double bonds because of the steric hindrance caused by acryl groups neighboring the unreacted double bonds. FT-IR and photo-DSC were used to determine the photopolymerization kinetics and double bond conversion (DBC). DMA indicated that vegetable oil-derived 3D prints undergo a glass transition from −3.6 to +6.6 °C, thus demonstrating viscoelastic properties at room temperature. Acrylated grapeseed oil (AGO) demonstrated superior tensile strength and Young's modulus with 0.49 MPa and 7.8 MPa, respectively. The syringe-based 3D printer approach makes it possible to print vegetable oil-based resins synthesized in the laboratory and reduce the required resin amount to a few milliliters, thus eliminating the excess amount of resin necessary for more commonly applied VAT printers.