The dispersion of carbon nanotubes in composite materials studied by computer simulation of Small Angle Scattering

Although numerous efforts have been made to reinforce ceramic materials by adding a nanostructured phase like carbon nanotubes (CNT), the appearance of aggregates during the manufacturing processes continues to be a problem. Given the size of the CNT (nm–μm), techniques such as Small Angle Scattering (SAS) can be a useful tool to study the formation of the aggregates and to quantify the degree of homogenization of the nanophase in the matrix. In this work, systems with different concentrations of CNT have been simulated in different states of aggregation, starting from a perfectly homogeneous dispersion of individualized CNT, and progressively aggregated. A Guinier regime appears in the scattering signal in the range of low values of the modulus of the scattering vector, q, as the aggregation occurs. Two parameters from the intensity curve are proposed to quantify the quality of the dispersion of the nanophase in the ceramic matrix. [Display omitted] •Simulation proves that typical amounts of CNT involve huge CNT-per-volume ratios.•Perfect dispersion is experimentally impossible with typical amounts of CNT, eg 1 wt%.•Typical amounts of CNT will inevitably lead to aggregates and hinder reinforcement.•Small angle scattering is a reliable tool for detecting the presence of aggregates.•SAXS can be useful for the assessment of the quality of the dispersion of the CNT.