Material extrusion 3D printing of carbon material reinforced PDMS matrix composites and their mechanical properties

Polydimethylsiloxane (PDMS) has been broadly exploited because of its advantages of biocompatibility, flexibility, and transparency. However, the low mechanical strength constraints its further applications. An approach to improve its mechanical properties is to reinforce the PDMS matrix with high mechanical strength reinforcements. Carbon materials, such as carbon fiber (CF) and carbon nanotube (CNT), are widely applied as reinforcement to enhance the mechanical performance of PDMS. 3D printing is a promising rapid prototyping method to manufacture carbon material/PDMS composites. Herein, we 3D printed CF/PDMS and CNT/PDMS lines, essential elements for printing 3D structures, to study the 3D printing process and mechanical performance of carbon material/PDMS composites. The rheological analysis indicated the adding of CF did not affect the printability of CF/PDMS inks. The tensile modulus of printed CF/PDMS lines was improved by 52.4% compared to pure PDMS lines with 4 wt% CF reinforced PDMS. The agglomeration of CNT in PDMS limited the improvement of Young’s modulus of printed CNT/PDMS lines as the CNT concentration increased. This work analyzed the influence of 3D printing parameters on the carbon material/PDMS lines. It also provided an approach to study the extrusion 3D printing process by analyzing the essential lines.