Dispersion, hybrid interconnection and heat dissipation properties of functionalized carbon nanotubes in epoxy composites for electrically conductive adhesives (ECAs)

Different types of MWNTs/epoxy composites were prepared with diglycidyl ether of bisphenol F (DGEBF) and bisphenol A (DGEBA) used as epoxy resins. MWNTs were functionalized to enhance the properties of epoxy composites by treatment with strong acids (acid-treated MWNTs, a-MWNTs) followed by m-phenylenediamine grafting (amine grafted MWNTs, m-MWNTs). Raw, a-, and m-MWNTs were dispersed in DGEBF or DGEBA to a concentration of 1 wt.%. X-ray photoelectron spectroscopy and thermogravimetric analysis verified the effectiveness of acid treatment and confirmed the amine-functionalization of the MWNTs. Scanning electron microscopy of the fracture surface of the epoxy matrix showed that chemical functionalization improves compatibility between the epoxy and MWNTs. Good dispersion of MWNTs leads to the improvement in coalescence and pull strength in the quad flat package (QFP) test. Further, the thermal conductivity of MWNTs/epoxy composites was higher than that of pure epoxy resins. In particular, the m-MWNT/epoxy composite has the best heat dissipation properties, due to the formation of an effective network for heat flow. (C) 2010 Elsevier Ltd. All rights reserved.