The effect of Al2O3 doped multi-walled carbon nanotubes on the thermal conductivity of Al2O3/epoxy terminated poly(dimethylsiloxane) composites

Al2O3 doped multi-walled carbon nanotubes (MWCNT) were synthesized as a conducting additive in alumina–epoxy terminated poly(dimethylsiloxane) (ETDS). The addition of Al2O3 doped MWCNT improved the thermal conductivity of the composites, which was a function of the Al2O3 loading. The mechanisms underlying this enhanced conductivity were examined in the context of the Hashin–Shtrikman (HS) boundaries and interconnectivity. The measured thermal conductivity revealed more enhanced thermal conductivity than expected by analytical predictions at a fixed micro Al2O3 concentration. Further analytical investigations showed that the addition of Al2O3 doped MWCNT affected the interconnectivity between the conducting particles because of their high aspect ratios. Overall, Al2O3 doped MWCNT may be useful for establishing three-dimensional heat conducting percolating networks in a matrix that affect the thermal conductivity of a composite.