Mechanical, thermal, and interfacial shear properties of polyamide/nanoclay nanocomposites

Abstract

There are increasing interests in using thermoplastics to replace thermosets to laminate fabrication due to their advantages such as high toughness, shorter manufacturing cycles, and reprocessing possibilities. The aim of the current study is to select appropriate thermoplastic nanocomposites, which fit the requirements of carbon fiber (CF) composites in the automotive industry. In order to achieve the target, this research has investigated the effect of nanoclay on the mechanical, thermal, and interfacial properties with de-sized CF of polyamide (PA6) composites. PA6/clay composites were characterized by different properties, namely, bending, tensile, impact, heat distortion temperature, interfacial shear stress, and scanning electron microscope. The micromechanism of plastic deformation after bending failure of PA6-clay nanocomposites is examined with different contents of nanoclay to correlate the microstructures with the mechanical properties. The results revealed that with 3% organo-clay filler content, flexural strength and modulus improved significantly by 42% and 52%, respectively, which could be explained by scanning electron microscopy images that show rougher fracture surface with adding clay into the PA6 matrix. The increased surface roughness implies that the path of the crack tip is distorted because of the silicate nano-layer, making crack propagation more difficult. The interfacial shear strength for 1 wt% of nanoclay was about the same as the neat PA6 but decrease dramatically with increasing contents of nanoclay.