Water resistance, mechanical, and morphological characteristics in polyamide-6/zirconium phosphate nanocomposites

Polyamide-6/organointercalated zirconium phosphate nanocomposites (PA-6/ZrPOct) were prepared by melt extrusion. The synthesized lamellar ZrP was expanded with octadecylamine at different amine:phosphate ratio, and its influence was evaluated by tensile test, melt flow rate, water absorption, rheology, scanning electron microscopy, and wide-angle X-ray diffraction. For all nanocomposites, the increase of modulus and decrease of elongation at rupture were observed. The decrease in water uptake was observed as the amine/phosphate increase, indicating that the presence of the amine reduces the hydrophilic nature of PA-6. Rheology revealed by pseudoplasticity indices that the nanofillers dispersion was homogeneous in all nanocomposites. Wide-angle X-ray diffractometry analysis showed that the characteristic basal spacing peak of pristine ZrP was absent for ZrOct 1:1 and 2:1. Also a high decrease in crystallinity was observed for PA-6/ZrOct 2:1 sample, which would be associated to plasticizing effect of octadecylamine avoiding crystallites formation. Evidences showed that structures with different degrees of intercalation and/or exfoliation could have been achieved.