Enhancing mechanical properties of 2D carbon/carbon composites via ZIF-67@CNTs-modified interfacial Layers: Mechanisms and performance optimization

Abstract

The interfacial bonding condition significantly governs the mechanical properties and performance of carbon/carbon (C/C) composites. This study presents a novel approach for constructing an interfacial layer modified by carbon nanotubes (CNTs) on the surface of carbon fibers (CFs), utilizing cobalt 2-methylimidazole (ZIF-67) as a catalyst precursor. Subsequently, the morphology of the interfacial layer within the cloth-laminated C/C composites was characterized, and the macroscopic and microscopic mechanical properties of CNTs-modified C/C (CNTs-C/C) composites were investigated. The out-of-plane compressive strength (OCS) and the interlaminar shear strength (ILSS) of the CNTs-C/C composites increased to 380 ± 19 MPa and 30.96 ± 1.43 MPa, respectively. These values represent remarkable increases of 85.4 % and 91.2 % compared to the C/C composites. The nanoindentation and fiber push-in tests revealed substantial improvements in both the interfacial layer strength and interfacial shear strength (IFSS) of the CNTs-C/C composites. The reinforced interfacial layer not only enhances crack propagation resistance but also strengthens the fiber-matrix bonding, thereby promoting CFs pull-out behavior. Furthermore, the high-strength interfacial layer exhibits enhanced load transfer efficiency to the CFs, thereby improve the overall load-bearing capacity of the composites. Consequently, the CNTs-C/C composites demonstrate superior comprehensive mechanical properties, achieving a flexural strength of 315 ± 14 MPa, representing a 57.5 % enhancement compared to the C/C composites.