Effect of multi‐walled carbon nanotubes addition on the interfacial property of titanium‐based fiber metal laminates

Multi‐walled carbon nanotubes (MWCNTs) were introduced to improve the interfacial properties of titanium‐based fiber metal laminates, and the corresponding reinforcement mechanism and failure behavior were revealed. Diverse weight fractions (0, 2.5, 5, 7.5 wt%) of MWCNTs were dispersed in polymerized monomer reactant (PMR) polyimide adhesives by ultrasonic dispersion. Single lap shear tests of samples were conducted and average shear strengths were experimentally measured to characterize the interface bonding strengths between the titanium and polyimide. The shear strength of this polyimide adhesive was further enhanced by incorporating MWCNTs, with over 87.5% improvement for the MWCNTs toughened adhesive joints with concentration up to 5 wt%. Meanwhile, the influence of MWCNTs on the interlaminar shear strength (ILSS) of the Ti/Cf‐PMR polyimide was investigated through short‐beam three‐point‐bending tests. It was found that MWCNT incorporation into the polyimide significantly enhanced the ILSS by 39.4%. Furthermore, scanning electron microscopy (SEM) was used to investigate the interface morphology, and the results of SEM images revealed MWCNTs failure morphologies, such as pull‐out, fracture, and bridging. The above results indicated the contribution of MWCNTs to the improvement of shear strength in these fiber metal laminates. POLYM. COMPOS., 39:E1159–E1168, 2018. © 2017 Society of Plastics Engineers