Thermally conductive and electrically insulative nanocomposites based on hyperbranched epoxy and nano‐Al 2 O 3 particles modified epoxy resin

Novel epoxy nanocomposites based on a diglycidyl ether of bisphenol A (DGEBA) epoxy, an epoxy functionalized hyperbranched polymer (HTTE) and nano‐Al 2 O 3 were synthesized with the aim of determining the effect of the nano‐Al 2 O 3 particles and HTTE on the structure and properties of epoxy nanocomposites. The mechanical properties, thermal conductivity, bulk resistivity, and thermal stability of the nano‐Al 2 O 3 /HTTE/DGEBA ternary composites were evaluated and compared with the corresponding matrix. The improvement in impact properties of these nanocomposites was explained in terms of fracture surface analysis by SEM. The results indicate that the incorporation of nanoparticles and hyperbranched epoxy effectively improved the toughness of epoxy composites without sacrificing thermal conductivity and bulk resistivity compared to the neat epoxy and Al 2 O 3 /DGEBA, obtaining a well dispersion of nanoparticles in epoxy matrix and solving the drawbacks for single fillers filled epoxy nanocomposite. Copyright © 2010 John Wiley & Sons, Ltd.