Kitchen blender outperforms ball milling in greener path to superstrong materials

Carbon nanotubes (CNTs) are renowned for their exceptional tensile strength and electrical conductivity. However, integrating multi-walled carbon nanotubes (MWCNTs) into polycarbonate matrices has been challenging due to their tendency to clump together. A recent study in Advanced Composites and Hybrid Materials by researchers from Adelaide University, Shenyang Aerospace University, and Southern Taiwan University of Science and Technology presents a novel approach using a kitchen blender to disperse MWCNTs effectively.

The study addresses the dispersion of MWCNTs in polycarbonate, a thermoplastic used in various applications. Properly dispersed CNTs can enhance the material's electrical and thermal conductivity, electromagnetic interference shielding, and mechanical strength. The researchers compared two mechanochemical techniques: traditional ball milling and a shear-dominated process using a kitchen blender in deionised water.

While both methods achieved some degree of dispersion, the blender method proved superior. It generated high shear, turbulence, and cavitation-assisted micro-jets that effectively separated CNT bundles with minimal defects. This method preserved the polycarbonate's molecular weight, ensuring the polymer's mechanical properties remained intact.

The resulting nanocomposites exhibited a 35% increase in tensile strength, a 77% rise in thermal conductivity, and a significant reduction in electrical resistivity. At a 20% CNT loading, the material achieved an electromagnetic interference shielding effectiveness of up to 24.2 decibels, making it a viable alternative to traditional metal shields.

This research highlights the potential of sustainable mechanochemical processes. The use of a kitchen blender with deionised water eliminates the need for chemical reagents, making the process environmentally friendly and scalable. The study suggests that the character of mechanical energy is crucial in determining the quality of CNT dispersion, with shear-dominated processes offering advantages over impact-driven methods.