Polyamide Nanocomposites: Investigation of Mechanical, Thermal and Morphological Characteristics

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).