3D Printing of a Robust Polyamide-12-Carbon Black Composite via Selective Laser Sintering: Thermal and Electrical Conductivity

The need for big volume powder materials in building mechanically robust sintered parts via selective laser sintering (SLS) has been observed considering the direction towards the future of mass fabrication. This work presents a facile approach of combining polyamide-12 (PA12) and carbon black (CB) powders to be used in the SLS application. The study investigates the mixing consistency, mechanical property, and thermal stability changes of the resulting 3D printed material. Bulk resistivity is correlated with the amount of CB, showing consistency of carbon content in the sintered parts produced by the effective separate grains mixing method. 3D printed parts are built with 0, 1.5, 3, 5 and 10 wt% CB via SLS. Improvements are seen at 1.5 and 3 wt% CB with the blockage of crack growth by the CB particles on applied load. For concentrations greater than 3 wt%, mechanical properties degrade due to hindering of physical contact between PA12 particles caused by CB particles, thereby reducing the effectiveness of the sintering process. The CB/PA12 sintered parts exhibit enhanced thermal stability resulting in higher degradation temperatures than the neat PA12. Therefore, in this study, thermally and mechanically enhanced 3D printed CB/PA12 build parts via SLS are successfully demonstrated.