The effect of microstructure on the dynamic mechanical properties of carbon fiber and carbon nanotube reinforced multi-scale composites with a polyamide 6 matrix

Abstract

We investigated the microstructure and the related dynamic mechanical properties of carbon fiber and carbon nanotube (CNT) reinforced, polyamide 6 (PA6) matrix multi-scale composites. Differential scanning calorimetry (DSC) showed that in composites reinforced with only carbon nanotubes, the aggregated nanotubes have a moderate crystal nucleating effect. However, in the hybrids, the carbon fibers and the uniformly dispersed CNTs have a notable crystal nucleating effect. It means that a crystalline interphase is formed around both the carbon fibers and the carbon nanotubes. As the interphase has higher modulus than the bulk matrix, it has an additional reinforcing effect and transfers the load better to the microfibers. We confirmed this theory by dynamic mechanical analysis.