Production of spherical semi-crystalline polycarbonate microparticles for Additive Manufacturing by liquid-liquid phase separation

Novel powder systems of good processability are essential to broaden the fields of application of powder-based Additive Manufacturing (AM) processes like selective laser sintering (SLS). Within this contribution a novel approach for production of semi-crystalline polycarbonate (PC) micron-sized particles is presented. The PC particles produced by liquid-liquid phase separation are thoroughly characterized with respect to powder and material properties using laser diffraction particle sizing, scanning electron microscopy (SEM), Raman spectroscopy, differential scanning calorimetry (DSC) and X-Ray diffraction (XRD). Remarkably, starting from amorphous feed material the process allows to obtain spherical semi-crystalline PC particles opening a thermal 'process window' for selective laser sintering. Dry particle coating with fumed silica further improves the flowability of the product particles. The powders' SLS processability was assessed by tensile strength measurements and powder deposition experiments. Dense thin layer specimen could be successfully built using the novel PC powder.