Structure and Properties of Polyamide-6 & 6/66 Clay Nanocomposites

Abstract

The structural, morphological and thermal properties of polyamide-6 and polyamide-6/66 clay nanocomposites have been studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and static and dynamic mechanical analysis. The wide-angle X-ray diffraction (WAXRD) and TEM results show the effects of clay loading in the polymer matrix. The polyamide-6 series show coexistence of intercalated and exfoliated structures and the polyamide-6/66 series show a complete exfoliated structure. Both series show the presence of a structural crystal phase transition. The dispersibility of organoclay in polyamide polymer and copolymer matrix is in agreement with the TEM image results. With an increase in clay content, there is a transformation from α to γ form of the polyamide-6 crystals. SEM observation indicates that the silicate particles are homogeneously dispersed in the polymer matrix without significant agglomeration even with an increase in clay loading. Thermogravimetric analysis reveals that the thermal stability increases with an increase in the clay content. DSC results show that as the clay content increases, the crystallization temperature increases, due to a strong heterophase nucleation effect. Static mechanical analysis show that the tensile strength, tensile modulus, heat distortion temperature and flexural strength increase with increase in clay loading for both the polyamide-6 and polyamide-6/66 series. On the other hand, elongation and impact decrease with an increase in clay loading in both the polyamide-6 and 6/66 series.