Synergistic interface and multiscale reinforcement in 3D carbon felt composites with GO, MWCNTs, and HCNTs

The study aims to enhance the performance of epoxy composites by incorporating various carbon-based materials, including 3D carbon felt (3DCFs), graphene oxide-carbon felt hybrids (GO@3DCFs), multi-walled carbon nanotubes combined with graphene oxide (MWCNTs-GO@3DCFs), and helical carbon nanotubes combined with graphene oxide (HCNTs-GO@3DCFs). Most epoxy composites are favored in use because of their good mechanical properties but their performance is usually restricted due to low stiffness, lack of thermal stability, and impact resistance. There are not enough studies focusing on the synthesis and performance improvement of epoxy composites with multi-scale carbon nanomaterials incorporated simultaneously in a systematic manner. To fill this gap, we employed Dynamic mechanical analysis and flexural testing as additional methods to understand how the different carbon fillers affect the storage modulus, glass transition temperature (Tg), flexural strength, and impact resistance of the composites. The study provides improvements considering in particular the increase of storage modulus of 154% as well as Tg of 30°C with MWCNTs-GO@3DCFs addition. Likewise, the increase was also observed when measuring the flexural strength and impact resistance, where the MWCNTs-GO@CFs reached a flexural strength of 251 MPa and impact strength of 21.6 kJ/m 2 . As for the HCNTs-GO@CFs, they recorded a flexural strength of 231 MPa and an impact strength of 25.3 kJ/m 2 . The reason for the improved performance is due to the nature of the carbon nanomaterials combined. More specifically, there is an improvement in load bearing, stress distribution, and performance of composite when HCNTs, MWCNTs, and GO are provided as a dense network.