Additive Manufacturing of Styrene-Isoprene-Styrene Block Copolymer Based Soft Thermoplastic Elastomeric Nanocomposites: Influence of Reduced Graphene Oxide on Microstructural, Mechanical and Functional Properties

Abstract

Additive manufacturing enables the customization of parts according to user requirements. However, additive manufacturing of soft polymeric materials using melt-based fused deposition modeling is challenging due to issues such as low column strength, high melt viscosity, poor adhesion with the print bed, and weak layer-to-layer adhesion. This work focused on the development of soft thermoplastic elastomeric nanocomposite materials based on reduced graphene oxide (rGO) and styrene-isoprene-styrene (SIS) triblock copolymer by direct ink writing (DIW) based additive manufacturing technique. The extrudability and printability of the developed SIS-rGO inks with varying rGO loading are investigated from shear viscosity and pressure drop analysis across different zones of the nozzle. Developed 3D printed nanocomposites showed good mechanical properties such as high elongation at break (≥ 2000%) and high tensile strength (5–11 MPa). Microstructures of 3D printed samples and the distribution of rGO nanosheets in the SIS matrix are analyzed from XRD and TEM. Dielectric constant of 3D printed nanocomposites increased ≈6 times for the 7 wt.% loaded rGO nanocomposite compared to the pristine SIS. Additionally, the electromagnetic interference shielding effectiveness (EMI SE) by absorption is also found to increase with rGO loading in the 3D-printed samples.