Two-step approach based on selective laser sintering for high performance carbon black/ polyamide 12 composite with 3D segregated conductive network

Abstract Material design is crucial for the preparation of conductive polymer composites (CPCs). In this work, a two-step approach based on selective laser sintering (SLS) technology was adopted to fabricate nano-carbon black (CB)/polyamide 12 (PA12) composites. CB/PA12 powders with predesigned coating structures were prepared in the first step and then sintered during the subsequent SLS step. Morphology characterizations demonstrate that CB particles are adsorbed onto the surface of PA12 powders as expected and have limited impact on the powder size. The effects of SLS condition and CB content on the thermal, mechanical and electrical properties of SLS parts were also investigated. Results reveal that the two-step approach can endow composites with preset conductive filler network and outstanding electrical property. The conductivity threshold is low at 0.87 wt%, which has never been reported in CB/PA12 composites before. Furthermore, the study proposes the formation mechanism of the segregated conductive network during the two-step process, which provides a new suggestion for the preparation of CPCs and suggests that two-step approach based on SLS facilitates the formation of 3D segregated network.