An investigation of thermal and mechanical properties of synthesised polyamide-6/γ-alumina composites

Abstract

Polyamide based composites were formed by melt blending of polyamide 6 (PA6) with a γ) -alumina powder toughened with ethylene–octene copolymer grafted by maleic anhydride (EOC-g-MAH) and also without EOC in a corotating twin screw extruder. Mechanical properties, morphological structure and thermal stability of toughened PA6 (PA6-g-EOC) and PA6-g-EOC/alumina composites were investigated in this study.To study the effect of powder loading of γ-alumina on the mechanical properties of the composites such as tensile strength, modulus of elasticity, break point and impact strength, varied amounts of 5, 10 and 15 wt-% were deployed. The toughened PA6–γ-alumina composites, i.e. blended by EOC-g-MAH, revealed higher impact strength and more toughness compared to that of the PA6–γ-alumina composites without EOC-g-MAH. Morphology of the composites was investigated by scanning electron microscopy (SEM) from the as moulded specimens. Micrographs showed a fine dispersion of γ-alumina particles in polyamide matrix due to appropriate mixing. Furthermore, thermal stability and degradation characteristics of the toughened PA6–γ-alumina composites were measured by thermogravimetric analysis. The addition of γ-alumina into the polyamide matrix showed an increase in thermal resistance so that thermal stability was increased by a rise in the powder loading.