Comparative Studies on Polyurethane Composites Filled with Polyaniline and Graphene for DLP-Type 3D Printing

Digital light processing (DLP)-type 3D printing ensures several advantages, such as an easy solution process, a short printing time, high-quality printing, and selective light curing. Furthermore, polyurethane (PU) is among the promising candidates for 3D printing because of its wide range of applications. This work reports comparative studies on the fabrication and optimization of PU composites using a polyaniline (PANI) nanomaterial and a graphene sheet (GS) for DLP-type 3D printing. The morphologies and dispersion of the printed PU composites were studied by field emission scanning electron microscope (FE-SEM) images. Bonding structures in the PU composites were investigated by Fourier-transform infrared (FT-IR) spectroscopy. As-prepared PU/PANI and PU/GS composites with different filler contents were successfully printed into sculptures with different sizes and shapes. The PU/PANI and PU/GS composites exhibit the improved sheet resistance, which is up to 8.57 × 10⁴ times (1.19 × 10⁶ ohm/sq) lower and 1.27 × 10⁵ times (8.05 × 10⁵ ohm/sq) lower, respectively, than the pristine PU (1.02 × 10¹¹ ohm/sq). Moreover, the PU/PANI and PU/GS composites demonstrate 1.41 times (44.5 MPa) higher and 2.19 times (69.3 MPa) higher tensile strengths compared with the pristine PU (31.6 MPa). This work suggests the potential uses of highly conductive PU composites for DLP-type 3D printing.