Dielectric and piezoelectric properties in selective laser sintered polyamide11/BaTiO 3 /CNT ternary nanocomposites

Polyamide11 (PA11)/BaTiO3/carbon nanotube (CNT) ternary nanocomposites (PBCNCs-3D) with 3D segregated percolation routes were fabricated by selective laser sintering (SLS) of CNT-coated PA11/BaTiO3 nanocomposite powder. The CNT-coated PA11/BaTiO3 nanocomposite powder show a higher laser absorption and wider sintering window than those of conventional PA11/BaTiO3/CNT ternary nanocomposite powders with a structure where CNTs are randomly distributed throughout the powder particles, endowing the composite powders with better sinterability. The 3D segregated conductive pathway was efficiently constructed in the PBCNCs-3D parts with a low percolation threshold of 0.3 wt%. The PBCNCs-3D parts showed a higher dielectric constant of 16.2 at a frequency of 1 kHz, which is approximately twice higher than that of SLS-printed composite parts (PBCNCs) without a segregated structure. Compared with PBCNCs, the piezoelectric strain coefficient increased from 1.7 to 2.1 pC/N. These results not only provide a new material for SLS processing but lay the groundwork to enhance the performance of piezoelectric polymer composites by constructing 3D segregated percolation routes.