Thermal and Dielectric Properties of 3D Printed Parts Based on Polylactic Acid Filled with Carbon Nanostructures

Abstract

Polylactic acid (PLA) containing 12 wt% of nanofillers, such as multi-walled carbon nanotubes (MWCNTs), graphene nanoplates (GNPs), is considered to obtain a non-conventional filament suitable for additive manufacturing (AM) process with enhanced thermal and electrical properties. In details, three-dimensional (3D) printed specimens obtained by means of fused deposition modeling (FDM) are experimentally characterized in terms of thermal conductivity and relative permittivity. The results are interpreted on the basis of the different features of the fillers and their interaction with the PLA, as evidenced by a morphological analysis. It is found better thermal transport by using two-dimensional (2D) shape nanoparticles (GNPs) with an improvement of about 260% respect to the unfilled polymer most likely due to its favorable arrangement and the lower thermal boundary resistance between the two phases, matrix, and fillers. Differently, mono-dimensional filler like MWCNTs is to be preferred in order to obtain higher value for the relative permittivity, due to the enhancement of the interfacial polarization and the presence of functionalized groups. It is found a value of 5.35 × 103 much greater than that of 3.7 measured for pure PLA. Given the good combined thermal and dielectric properties, such materials are promising candidates for packaging applications with electromagnetic (EM) shielding capability.