UV-assisted three-dimensional printing of polymer nanocomposites based on inorganic fillers

In this work, nanocomposites based on a UV-curable polymeric resin and different inorganic fillers were developed for use in UV-assisted three-dimensional (UV-3D) printing. This technology consists in the additive multilayer deposition of a UV-curable resin for the fabrication of 3D macro structures and microstructures of arbitrary shapes. A systematic investigation on the effect of filler concentration on the rheological properties of the polymer-based nanocomposites was performed. In particular, the rheological characterization of these nanocomposites allowed to identify the optimal printability parameters for these systems based on the shear rate of the materials at the extrusion nozzle. In addition, photocalorimetric measurements were used to assess the effect of the presence of the inorganic fillers on the thermodynamics and kinetics of the photocuring process of the resins. By direct deposition of homogeneous solvent-free nanocomposite dispersions of different fillers in a UV-curable polymeric resin, the effect of UV-3D printing direction, fill density, and fill pattern on the mechanical properties of UV-3D printed specimens was investigated by means of uniaxial tensile tests. Finally, examples of 3D macroarchitectures and microarchitectures, spanning features, and planar transparent structures directly formed upon UV-3D printing of such nanocomposite dispersions were reproducibly obtained and demonstrated, clearly highlighting the suitability of these nanocomposite formulations for advanced UV-3D printing applications. POLYM. COMPOS., 38:1662-1670, 2017. (c) 2015 Society of Plastics Engineers