Characterizing polydimethylsiloxane–carbon nanotubes composites manufactured using material extrusion additive technology: A rheological and mechanical analysis

Abstract

Direct Ink Writing (DIW) revolutionizes 3D printing with carbon-based inks, offering design, complexity, and sustainability advantages. This study centers on formulating Polydimethylsiloxane (PDMS) and Multiwalled-Carbon Nanotube (CNT) nanocomposite-inks, assessing their rheological properties for DIW suitability and minimum reinforcement demands. Mechanical tests on DIW-fabricated samples are conducted under static and dynamic conditions substantiated by fractographic analysis. Rheological investigation confirms a 3 wt% reinforcement threshold for printability. Comparatively, 3.5 wt% CNT nanocomposites exhibit a substantial 143% increase in elastic modulus over neat PDMS. Dynamic mechanical analysis reveals heightened storage modulus with increasing CNT content, while fractography underscores localized areas resisting fracture, demanding elevated stress for breakage.