Reprint of Study of spatial distribution of sepiolite in sepiolite/polyamide6,6 nanocomposites

• Polymer chains are expanded due to the arrangement of sepiolite in injection molded sep/PA66 CPN.
• Sepiolite fibers are properly dispersed in the polymer matrix.
• SAXS analysis and electron density difference are suitable tools to quantify the dispersion of the filler in CPN.

The enhancement of the technical properties of a Clay/Polymer Nanocomposite (CPN) is related to the homogeneity and dispersion of the filler within the polymer matrix. In this work, samples of pure polyamide 6,6 (PA66) and reinforced PA66 with 1, 3, 5, 7 and 9 wt.% of sepiolite have been studied. The samples have been qualitatively analyzed with different microscopy techniques and with X-Ray diffraction and scattering techniques. The images obtained by confocal microscopy show that the sepiolite is homogeneously distributed in the PA66 matrix. The micrographs taken by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that sepiolite fibres are oriented and equidistantly distributed even in the samples with high percentages of sepiolite. TEM images reveal the absence of clusters of sepiolite and good dispersion of the reinforcement within the matrix. The quantification of the dispersion, calculated from the results of Small Angle X-Ray Scattering (SAXS), indicates that the polymer chains are expanded due to the arrangement of sepiolite within the PA66 matrix and that the fibres are properly dispersed in the polymer.