Halloysite Nanotube Loaded Polyamide Nanocomposites: Structural, Morphological, Mechanical, Thermal and Processing Behaviors

Abstract

In this study, the polyamide 6 (PA) matrix was reinforced with the purified, fine ground and amino-silane treated halloysite nanotubes (HINT) at different concentrations. The preparation of composites was carried out using a lab-scale twin-screw micro-compounder with loading ratios at 0.5, 1, 3, and 20% by weight, and the test samples were prepared by the injection-molding process. According to mechanical test results, additions of HINT to the PA matrix caused slight improvements in tensile strength and Youngs' modulus parameters. The optimum concentrations for all of the additives used were estimated by comparison of mechanical test data. The addition of amino silane-modified HINT resulted in a higher impact performance at high loading levels up to 3% concentrations. Further addition of HINT caused a reduction in the mechanical parameters of composites. Thermal studies revealed that the glass transition temperature of PA shifted to higher values after HINT mineral inclusions. Thermo-mechanical results showed that storage moduli of PA exhibited improvement with an increase in HINT content. The distributions of HINT clay into the PA phase were visualized with SEM images. Based on these observations, a high level of dispersion homogeneity was achieved for lower filling ratios. According to melt-flow and force measurements, composites filled with 20% of HINT displayed a remarkable increase in exerted force during melt-blending.