Effect of carbon nanotubes on electrical and mechanical properties of multiwalled carbon nanotubes/epoxy coatings

In the present study, attempts were made to enhance conductivity of electrocoats (based on epoxy amine adduct) containing NH₂-multiwalled carbon nanotubes (MWCNTs). The weight percent of incorporated MWCNTS into the electrocoat matrix varied in the range of 0.6–3.6 wt% to obtain a series of electrocoatings. These were then applied on steel substrates by a cathodic electrodeposition technique. Electrocoated films were characterized utilizing scanning electron microscopy and optical microscopy. The results illustrated that electrical conductivity was enhanced by increasing of the MWCNT load. At the percolation threshold, throwing power was dropped while the recoating ability was enhanced. Mechanical behavior of nanocomposites containing MWCNTs in the range of 0–2.8 wt% was investigated by dynamic mechanical thermal analysis (DMTA) and nanoindentation test methods. DMTA analysis revealed that the width of tan δ was increased by the addition of nanotubes up to 2.8 (wt%). Also, the results obtained from the nanoindentation test showed that the elastic modulus and hardness of the nanocomposites were decreased by the addition of MWCNTs.