Mechanical characterization of 3D printed multiscale carbon nanofiller/continuous fiber reinforced polymer hybrid composites

Abstract Mechanical properties of 3D printed continuous fiber reinforced polymer composites (CFRPCs) are generally lower than expected due to unavoidable voids and weak interfacial adhesion. However, previous research work has rarely been reported on introducing carbon nanofillers such as carbon nanotubes (CNTs) and graphene oxide (GO) to reduce internal void defects and improve interfacial adhesion of CFRPCs. In this work, an innovative means of introducing CNTs and GO is proposed to reduce internal void defects and improve interfacial adhesion for enhancing the mechanical properties of 3D printed hybrid CFRPCs. Polyethylene terephthalate glycol (PETG) is employed as a polymer matrix due to its excellent processability for the 3D printing process. Continuous basalt fiber (CBF) is selected as a microscale filler due to its high mechanical properties, low cost and availability for additive manufacturing. It is shown that introducing carbon nanofillers into PETG leads to notably reduced porosity and greatly improved interfacial adhesion between CBF and PETG. As a result, the mechanical properties of 3D printed hybrid CFRPCs are significantly enhanced by introducing carbon nanofillers into the polymer matrix. Finally, the mechanisms of CNTs and GO are analyzed for enhancing the mechanical properties of 3D printed hybrid CFRPCs. The multiscale filler enhancement method has the characteristics of low cost and easy implementation. This approach contributes a novel idea for preparing high‐performance 3D printed CFRPCs by reducing internal void defects and enhancing interfacial adhesion by simply introducing carbon nanofillers. This method can expand material systems and provide a new development idea for industrial applications. Highlights Proposed a new means to improve the mechanical properties of 3D printed CFRPCs. The performances of PETG composites are enhanced by optimal CNT or GO content. Combination of carbon nanofillers with PETG enhances interfacial adhesion.