Polyamide Nanocomposites: Investigation of Mechanical, Thermal and Morphological Characteristics

Abstract

In the present work, polyamide/CaSO₄ nanocomposites were prepared via melt intercalation on twin-screw extruder. Different particle sizes (23, 15, 10 nm) of CaSO₄ were synthesized by in situ deposition technique and its sizes and shape were confirmed on a transmission electron microscope (TEM). The TEM study showed that nano-CaSO₄ has a needlelike or fiberlike structure. Nano-CaSO₄ was added from 1 to 4 wt% in the polyamide. Properties such as Tensile strength, Elongation at Break, Young's Modulus, and hardness were studied. These results were then compared with commercial CaSO₄-filled polyamide composites. There was a propounding effect to be observed on properties of polyamide nanocomposites due to uniform dispersion of nano-CaSO₄ and commercial CaSO₄. The 4 wt% of 10 nm CaSO₄ shows 16% improvement in Tensile Strength compared to commercial CaSO₄ (11%) filled in polyamide composites, whereas, Elongation at Break decreases drastically in 10 nm CaSO₄-filled polyamide nanocomposites up to 22% compared to commercial CaSO₄-filled polyamide composites at 4 wt% loading (11%). Among these properties, Young's Modulus was found to be more effective in 4 wt% loading of 10 nm CaSO₄ and was recorded to be 66% more compared to commercial CaSO₄-filled-in polyamide composites (22%). Moreover, thermal properties such as thermal degradation and flammability were studied by TGA and flame testers. It was found that nano-CaSO₄ was thermally more stable compared to commercial CaSO₄-filled polyamide composites. Extent of dispersion of nano-CaSO₄ was studied along with micro cracks generated during tensile testing using an Atomic Force Microscope (AFM).

Keywords:

• Flame retardancy
• Mechanical properties
• Nano-CaSO₄
• Polyamide 66
• Thermal properties