Effect of Molybdenum Disulfide (MoS2) Reinforcement on the Structural, Thermal, Mechanical, and Tribological Analysis of Novel Polyamide 6,6 (PA 6,6) Composites

Developing nanomaterial-based polymer composites by reinforcing fillers at various concentrations is an effective approach to achieving enhanced mechanical, tribological, and other desirable properties. In this study, novel MoS2-reinforced PA-6,6 (PM) composites were fabricated using melt-mixing and injection molding techniques, incorporating MoS2 fillers at different loadings. The surface morphology and microstructure of dispersed MoS(2)were analyzed using field-emission scanning electron microscopy (FESEM), while Fourier transform infrared spectroscopy (FTIR) confirmed the presence of key functional groups. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results revealed the strong heterogeneous nucleation ability of MoS2, significantly enhancing the crystallization temperature and thermal stability of the PM composites. Compared to pure PA-6,6, the melt-blended PM composites demonstrated improved hardness and tensile properties, with a similar to 21% increase in tensile strength observed for 5 wt.% MoS2 filler. Detailed analysis of the fracture surface elucidated the fracture mechanisms, strengthening characteristics, and interfacial adhesion within the composites. Conversely, the impact resistance showed a decline relative to pure PA-6,6. Tribological performance, evaluated via linear reciprocating tribology (LRT) tests under varying abrading frequencies and normal loads, indicated improved friction and wear characteristics at 5 wt.% MoS2. Worn surface analysis revealed a smoother morphology, confirming the composite's superior wear resistance followed by an adhesive wear mechanism.