Alignment of multi-walled carbon nanotubes in a polyethylene matrix by extrusion shear flow: mechanical properties enhancement

This article discusses the effect of shear rates on the alignment of Multi-walled Carbon Nanotubes (MWCNTs) in a polyethylene (PE) matrix. Shear forces were applied with a self-constructed controllable shear extrusion system, and the degree of orientation of the MWCNTs was analyzed through image analysis of the microtome sectioned surfaces. Partially aligned MWCNTs in a PE matrix are successful fabricated in this study. It was found that the degree of alignment was increased by increasing shear rates, and an optimal shear rate was discovered. Tensile test results indicate that the mechanical properties of composites increase with an increasing degree of CNTs alignment. A partially aligned MWCNTs PE composite exhibited greater mechanical properties than randomly oriented MWCNTs. Differential scanning calorimetry analysis revealed that MWCNTs alignment by shear flow extrusion played a major role in mechanical property enhancement as compared to the crystallization effect of the polymer.