Development of high temperature stable isotropic conductive adhesives

In this paper, a novel isotropic conductive adhesive containing different fillers, which shows better properties at high temperature compared with traditional ones, was developed and the properties of various fillers were investigated. Silver flakes as the main filler and secondary materials such as silver nanoparticles, carbon nanotubes (CNT) with different volume ratios are combined to form bi-modal or tri-modal systems for electrical or thermal conduction. The curing behavior of the adhesive was investigated by differential scanning calorimeter (DSC). The properties such as glass transition temperature (Tg), storage modulus were detected by dynamic mechanical analyzer (DMA). Thermogravimetric analysis (TGA) was used to determine the decomposition behavior. The distribution of the carbon nanotubes used in the adhesive was also characterized by SEM. The glass transition temperature of the formulated adhesives is above 200 degC. The in-plane bulk electrical resistivity (lower than 5.2*10-5 Omega*cm)as well as the shear strength (up to 15 MPa) of the adhesives with different volume percentages of various fillers were also obtained.