Additive manufacturing of PA12 carbon nanotube composites with a novel laser polymer deposition process

The facile manufacture of PA12 MWCNT/silica (50/50 by weight) nanocomposite powders through a high energy mixing process is presented, which are useful to generate 3D objects by a novel Laser Polymer Deposition (LPD) process. The mixing as well as the LPD process led to no discernible changes in the material properties (DSC, SEM, LD) of the core-shell nanocomposites, enabling the recycling of unconverted powder. The built parts yield ultimate tensile stresses and Young's modulus at 10%-20% of the bulk material. Partially unmolten particles and voids were identified as the main mechanical failure mechanism in the built parts. The mechanical properties are better with low additive content (Young's modulus: 89.8 +/- 5.4 MPa; UTS: 12.9 +/- 5.3 MPa with 0.25 wt% additives). Electronic conductivity up to the region of moderate conductivity could be achieved by multiwalled carbon nanotube (MWCNT) network formation (8 x 10(-4) S cm(-1) at 1.25 wt% of additives). A variant of the processing strategy revealed that a higher mechanical strength can be achieved by a laser induced remelting of the traces following their initial construction.

Automated summary

The facile manufacture of PA12 MWCNT/silica nanocomposite powders through a high energy mixing process enables the generation of 3D objects using Laser Polymer Deposition. The built parts exhibit mechanical properties comparable to 10%-20% of the bulk material, with main mechanical failure mechanisms identified as partially unmolten particles and voids. The mechanical properties are improved with low additive content, and electronic conductivity can be achieved through the formation of a MWCNT network.