Effect of carbon nanotube (CNT) functionalization in epoxy-CNT composites

Abstract

The effect of carbon nanotube (CNT) functionalization in altering the properties of epoxy-CNT composites is presented. The presence of functional groups effectively influenced the colloidal behavior of CNTs in the precursor epoxy resin and the hardener triethylenetetramine (TETA), which affected the synthesis process and eventually the interfacial interactions between the polymer matrix and the CNTs. The physical, thermal, and electrical properties of the composites exhibited strong dependence on the nature of functionalization. At a 0.5-wt% CNT loading, the enhancement in tensile strength was found to be 7.2%, 11.2%, 11.4%, and 14.2% for raw CNTs, carboxylated CNTs, octadecyl amide-functionalized CNTs, and hydroxylated CNTs, respectively. Glass transition temperatures (Tg) also varied with the functionalization, and composites prepared using hydroxylated CNTs showed the maximum enhancement of 34%.