A processing-induced clay dispersion and its effect on the structure and properties of polyamide 6

The nanostructures and morphologies of polyamide 6 (PA6)/organoclay nanocomposites prepared by melt compounding have been studied by using X-ray diffraction (XRD) and transmission electron microscopy (TEM). A combination of XRD and TEM indicates that an exfoliated clay morphology dominates at low clay loadings (≤5wt%) and a mixture of intercalated and exfoliated structures exists at high clay concentrations. It is worth noting, however, that optical microscopy (OM) even shows the presence of large clay agglomerates in samples with higher clay contents. OM images further present an overview of an uneven clay distribution due to the effect of injection molding. The crystalline structure of PA6 is greatly affected by this unevenness in the processing-induced clay dispersion, as evidenced by differential scanning calorimetry (DSC). The thermal dynamic and mechanical properties of PA6 and the nanocomposites have been investigated as a function of clay concentration. The tensile tests show that the degree of dispersion of the nanoclay within the polymer matrix plays a vital role in property improvement.