Effective thermal conductivity of 3,5‐diaminobenzoyl‐functionalized multiwalled carbon nanotubes/epoxy composites

Abstract

ABSTRACT To obtain homogeneous dispersion and good interfacial interaction between MWCNT and polymer matrix, the functionalization of MWCNTs with 3,5‐diaminobenzoic acid (DAB) via a direct Friedel‐Crafts acylation was accomplished. FTIR, XPS, and FT‐Raman analysis was performed to confirm that diaminobenzoyl moieties were successfully grafted onto MWCNT surface with less structural damage. The incorporation of diaminobenzoyl‐functionalized MWCNTs (DAB‐MWCNTs) into epoxy matrix can substantially enhance storage modulus ( E ′) as well as glass transition temperature ( T g ) and reduce the coefficient of thermal expansion. The thermal conductivity enhancement can be observed with DAB‐MWCNTs probably due to good dispersion and decreased interfacial thermal resistance between MWCNT and polymer matrix. The Maxwell‐Eucken, Lewis‐Nielsen, and MG‐EMA models were used to evaluate theoretical thermal conductivity. Moreover, epoxy resin incorporated with hybrid fillers, which consisted of DAB‐MWCNTs and silicon nitride exhibit higher thermal conductivity than those with single filler, thereby forming perfectly heat conductive pathways. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3184–3196, 2013