Improvement of thermal, electrical, and tribological performances of GnPs composites produced by selective laser sintering

In the present work, Graphite nanoPlatelets/Polyamide-12 (GnPs/PA-12) particle composites were produced through additive manufacturing (AM). The selective laser sintering (SLS) technology was used to manufacture 3D-printed composite components by means of a powder mix of GnPs and PA-12. The analyzed combination of technology and materials allows to obtain parts with improved thermal, electrical, and tribological properties, while maintaining a low production cost. In total were realized 5 different scenarios, each one with a different wt% of the GnPs reinforcement (2-4-6-8-10 wt%), and compared the results to the PA-12 matrix. Experimental tests were performed to study the morphology (profilometry, SEM, wettability), the electrical conductivity under different normal loads (0.1–1 kN), the thermal performance, and the tribological properties of each sample. The results show that the increase of GnPs particles dispersed in the matrix leads to a hydrophobic behavior of the surface. An improvement in electrical conductivity (from 10−11 S/cm of the pure PA-12 matrix to 10−4 S/cm of the 10 wt% GnPs) and thermal performance (33,6% improvement for the best-case scenario compared to the bare matrix) was observed. Tribological tests underlined a reduction of 25% in friction coefficient and an improvement of 80% in wear resistance compared to the PA-12 matrix. Highlights: 3D printed GnPs/PA-12 composites does not exhibit any significant geometrical alteration. GnPs enable hydrophobic surfaces with increased contact angles. Electrical conductivity improved from 10−11 S/cm of the unfilled PA-12 matrix up to 10−4 S/cm, for the 10 wt% GnPs sample. Thermal performance improves up to 33.6% with GnPs reinforcement. 10 wt% GnPs reduces friction by 25% and wear by 81%.