Thermo-mechanical behavior of epoxy composites modified with reactive polyol diluent and randomly-oriented amino-functionalized multi-walled carbon nanotubes

The effect of a multifunctional reactive diluent and toughener, an epoxy-terminated polyether polyol, and amino-functionalized multi-walled carbon nanotubes (NH2-MWCNTs) on the thermo-mechanical behavior of three-phase (epoxy/polyol/NH2-MWCNTs) toughened epoxy composites was investigated. Thermo-mechanical behavior of the composites was evaluated by dynamic mechanical analysis (DMA) and thermal mechanical analysis (TMA). The addition of epoxy-terminated polyether polyol to the epoxy resin caused a slight decrease in thermo-mechanical properties of resin systems. However, the addition of a very small amount of NH2-MWCNTs into the polyol-toughened epoxy considerably increased the glass transition temperature, storage and loss moduli, damping properties and coefficient of thermal expansion (CTE) of the composites. The inclusion of the polyol in the resin system resulted in a more flexible system and a corresponding decrease in the thermo-mechanical properties. However, incorporation of a uniformly dispersed 0.3 wt.% loading of NH2-MWCNTs into the polyol-toughened epoxy composites improved the properties compared with pristine and polyol-toughened epoxy composites due to improved crosslink interactions among NH2-MWCNTs, epoxy-terminated polyol and epoxy resin.