Surface Modification Of Carbon Fiber Based On MOF And Research On Properties Of Interface And Wave Absorbing

Carbon fibers(CF)and carbon fiber reinforced composites(CFRC)were widely used in various high-tech fields due to their excellent properties.However,the chemical inertness on the surface of CF seriously affected their interfacial properties,limiting their further development.The nanoscale reinforcements grafted on the surface of CF can improve the interfacial properties of the composites.Therefore,metal-organic framework(MOF)with high specific surface area and abundant reaction sites were selected to strengthen the interfacial properties and ability of electromagnetic wave absorption of CFRC in this paper.With purpose of improving interfacial mechanical properties of the CFRC and revealing the interfacial enhancement mechanism of hierarchically reinforced structures,a novel hierarchical reinforcement structure(Zn O-MOF)containing zinc oxide(Zn O)and metal-organic framework(MOF)was built on the surface of CF in this paper.The sheet-like Zn O-MOF structure can strengthen the mechanical interlocking between the CF and epoxy,and introduced a dual-platform modulus transition layer to the interfacial region which can deliver load from resin to CF efficaciously.Compared with the untreated CFs,the transverse fiber bundle tensile(TFBT)strength and the interfacial shear strength(IFSS)of the composites reinforced by modified T700 CFs was increased by 51.8% and 64.7%,respectively.These results indicate that the Zn O-MOF structure is promising with practical value in endowing CF composites more excellent interfacial properties.In order to further explore the influence of different type MOF structures on the interfacial properties and functional application prospects of CF,CF modified by iron-cobalt composite MOF(CF-Fe/Co-MOF)were prepared by in situ growth in this paper.The MOF structure which introduced a modulus transition platform at the interface enhanced the bonding between CF and resin matrix.The IFSS and TFBT strength of the CF-Fe/Co-MOF improved by 49%and 41.2%.In addition,the modified CF was annealed.The treated samples,especially the annealed CF-Fe/Co-MOF samples(CF-Fe/Co-C),exhibited improved electromagnetic wave absorption performance.The minimum reflection loss(RL)of the CF-Fe/Co-C reached-88.2 d B,and the IFSS of CFFe/Co-C was still nearly 42.9% higher than that of commercial CF.The results showed that the establishment of structures based on MOF had a bright prospect in the research of structure-function integration.