Obtenção de filamentos para impressão 3D a partir de nanocompósitos de poli (ácido láctico), nanotubo de carbono e óxido de grafeno

Abstract

This work aims to develop nanocomposite filaments based on poly(lactic acid) (PLA) incorporated separately with carbon nanotubes (CNTs) and graphene oxide (GO), for application in additive manufacturing processes using Fused Deposition Modeling (FDM). Initially, the materials were characterized in terms of their structural, chemical, thermal, and morphological properties using techniques such as XRD, Raman spectroscopy, FTIR, SEM, TEM, and TGA. Filaments were produced by extrusion, varying nanoparticle concentrations (0.2 to 1 wt.%) and processing temperatures (190 °C to 230 °C), as defined by a Design of Experiments (DOE) approach. The results indicated that the addition of carbon nanotubes (CNTs) did not lead to significant improvements in the tensile strength or elastic modulus of PLA; however, it maintained mechanical strength, hardness, and thermal stability values comparable to those of pure PLA, without compromising material integrity. Sample A1 (PLA/0.2% CNT – 190 °C) exhibited a tensile strength of 47.61 MPa, comparable to that of neat PLA (47.23 MPa), and similar Shore D hardness, indicating good mechanical stability. On the other hand, the nanocomposites with graphene oxide (GO) showed inferior performance: sample A7 (0.2% GO – 230 °C) reached 41.01 MPa, while A6 (0.2% GO – 190 °C) recorded 38.81 MPa, demonstrating reduced mechanical properties, mainly attributed to poor dispersion and agglomerate formation within the polymer matrix. Sample A4 (1.0% CNT – 190 °C) presented the lowest tensile strength (23.36 MPa), highlighting the negative effect of excessive filler content and reduced melt flow. Therefore, it is concluded that, although none of the nanocomposites resulted in a significant enhancement of PLA properties, the formulation containing 0.2% CNT processed at 190 °C exhibited superior thermal stability and overall mechanical performance compared to the GO-based compound, making it the most suitable for FDM-based additive manufacturing applications.