Composite materials with MWCNT processed by Selective Laser Sintering for electrostatic discharge applications

Abstract

Selective Laser Sintering (SLS) is an additive manufacturing technology that enables the production of polymeric parts for end-use applications. Despite the great potential of conventional materials, carbon-based reinforcements have been widely considered to contradict the electrically insulating nature of polymers, allowing the applicability of SLS in novel applications within electronics industry. However, the laser-sintering processing of such materials still encompasses a number of limitations including agglomeration problems, weak interparticle adhesion, low parts resolution, high processing time and costs. Therefore, this research reports the development of functional composite materials for SLS capable of being considered for the production of components that are in direct contact with electrostatic discharge (ESD) sensitive devices. To do so, composite materials of Polyamide 12 incorporating 0.50 wt%, 1.75 wt% and 3.00 wt% of Multi-Walled Carbon Nanotubes were developed aiming to achieve values of surface resistance between 104 - 109 Ω, according to the delivery instructions of Bosch Car Multimedia S.A. Test specimens produced by SLS were dimensionally, mechanically, electrically, thermally and morphologically characterized. Comparing to the neat matrix, the composite materials revealed narrower SLS processing window, reduced mechanical strength, surface resistance in the ESD range and electrical conductivity until 10−6 S/cm. Fundamentals on the sintering process of these functional materials are also provided.