Mechanical and crystallographic properties of injection‐molded polyamide 66/sepiolite nanocomposites with different clay loading

Polyamide66 (PA66) and polyamide66/sepiolite (PA66/sepiolite) nanocomposites at 1, 3, 5, 7, and 9 wt% clay loading were prepared and injected to simulate industrial processing. Tensile tests were performed in the samples, and scanning electron microscopy was used to characterize the fracture surface. The samples were also examined by X‐ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), and vibrational spectroscopy analysis (FT‐IR and FT‐Raman). Higher tensile strength and stiffness and reduction of the strain to failure are observed in the nanocomposites with higher sepiolite content. Two‐dimensional XRD analyses show that the sepiolite also enhances the orientation of PA66 crystals. XRD and spectroscopic analyses corroborate that the nanoclay fibers are placed between the lamellar superstructure of the PA66 without affecting the polymer chains. DSC confirms that the presence of sepiolite does not influence the crystallinity nor the nucleation of PA66 as the arrangement of the fibers between the PA66 lamellae hinders the nucleation of new crystals. We propose a model for the crystallographic organization of the organic and inorganic phases in the PA66/sepiolite nanocomposites. POLYM. COMPOS., 36:2326–2333, 2015. © 2014 Society of Plastics Engineers