Alodi Pascal, Eneko Iruretagoyena, Itxaso Calafel, Mercedes Fernández, Gonzalo Guerrica-Echevarria, Nora Aranburu, Robert Aguirresarobe
The combination of electrical functionality and the possibility of fabricating 3D shapes by additive manufacturing have been a trend in polymer research in the last years. Among different options, the incorporation of carbon nanofillers, such as multiwalled carbon nanotubes (CNT), is considered an easy but effective way to achieve electrically conductive 3D printable materials. However, the electrical properties are highly dependent on the manufacturing method and the processing conditions employed. This study presents the development of 3D-printable CNT nanocomposites based on poly(butylene succinate-co-adipate) (PBSA), with particular focus on the influence of applied shear during manufacturing on their electrical performance. It was found that the electrical behavior of the nanocomposites depends on the shear rate applied during processing. Specifically, higher CNT contents are required to achieve electrically conductive 3D-printed parts in comparison to those produced via compression molding. The effect of shear was simulated through the coupling of rheology and electric conductivity measurements, and a protocol capable of simultaneously measuring viscosity and electrical conductivity is proposed. This methodology allowed the identification of a processing window in which the nanocomposites retained their electrical conductivity during shear in the molten state.