Investigação das propriedades elétricas e mecânicas de resina fotossensível para impressão 3D – DLP modificada com grafite

Abstract

This work investigated the modification of a photopolymer resin of the ABS-Like type, used in 3D printing by DLP technology, through the addition of graphite in different concentrations, with the aim of understanding the influence of this conductive filler on the electrical, mechanical properties, and printing quality of the material. Test specimens containing up to 10% by mass of graphite were produced and evaluated through tensile testing, impedance spectroscopy, optical microscopy, Fourier-transform infrared spectroscopy, and printability analysis. The results indicated a gradual increase in electrical conductivity with the addition of graphite, especially from 3%, while the mechanical strength showed a linear decrease with increasing concentration. The morphological analysis revealed that the presence of graphite interferes with the formation of layers during printing, reducing the thickness of the laminations and impairing their adhesion, an effect more evident in formulations with higher load content. The sample with 10% graphite, for example, showed structural failures that prevented mechanical testing, although it was possible to visually analyze it, identifying delaminations possibly caused by excessive loading and the reduced effective height of the printed layers. Nevertheless, the formulations with 5% graphite proved to be viable, maintaining a good balance between electrical conductivity, mechanical strength, and print fidelity, enabling the production of parts with satisfactory performance. The results indicate the potential of incorporating conductive fillers into photopolymer resins to enhance functionalities, suggesting promising applications in printed sensors, electrostatic discharge (ESD) materials, and lightweight electromagnetic shielding, thus expanding the possibilities of functional additive manufacturing in multifunctional devices and protection of sensitive circuits.