Study on metal decorated oxidized multiwalled carbon nanotube (MWCNT) - epoxy adhesive for thermal conductivity applications

In this work, an effort has been made to develop a new type of complex conductive adhesive filled with silver decorated multi-walled carbon nanotubes (Ag-MWCNT). MWCNTs have been modified using N,N-dimethyl formamide (DMF) as a reducing agent and silver nanoparticles (Ag-NPs) has been homogeneously decorated against the surface. Fourier transform infra-red spectroscopy (FTIR) and Raman spectroscopy concluded that carboxylic groups were anchored to the surface of nanotubes. X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS) confirmed that Ag-NPs were formed and uniformly deposited onto the surface of carboxylic functionalized MWCNT. Test results indicated an improvement in the thermal conductivity up to 0.88 W/mK, which was about four-fold increase over pristine epoxy. The curing kinetics of Ag-MWCNTs reinforced epoxy adhesive system was also studied using non-isothermal differential scanning calorimetric (DSC) technique. The activation energy obtained by Kissinger’s method was reduced from 57.2 to 54 kJ/mol with an addition of 0.5 wt% of Ag-MWCNT within unmodified epoxy. Lap shear strength of the adhesive containing 0.5 wt% of Ag-MWCNT was higher than the pristine polymer thus confirming reinforcing effect of Ag-MWCNT in conductivity applications.