Electrical and mechanical properties of CNT/CB dual filler conductive adhesives (DFCAs) for automotive multi-material joints

摘要

A type of CNT/CB dual filler conductive adhesives (DFCAs) was developed and its potential application in automotive components was explored. An electrical conductivity model which takes into account different shapes and dimensions of dual fillers was established to determine the most economical CNT/CB formula to be marginally over the conductivity threshold. The influence of CNT to CB ratio, as well as total weight percentage of nanofillers on the electrical resistivity, and the mechanical and piezoresistive behavior of DFCAs were investigated experimentally. The static and dynamic responses of DFCAs used as functional adhesives in an automotive multi-material hatchback were evaluated by finite element simulation. The results indicate that the CNTs provide better mechanical and electrical properties than CB; conversely, CB provides better economy and less agglomeration. The optimal ratio with the best balance between performance and economy for a total filler content of 2 wt% CNT/CB DFCAs is CNT:CB = 1:3. When DFCAs are applied as functional adhesives in a multi-material hatchback, the overall bending and torsion stiffness improve by 2.5% and 8.7%, respectively, while the crashworthiness is maintained at a safe level. This indicates a potential application of CNT/CB DFCA functional adhesives in lightweight and low-cost structural health monitoring.