Polymer nanocomposites from self-assembled polystyrene-grafted carbon nanotubes

Abstract

Herein we demonstrate the use of supramolecular self-assembly and anisotropic patchiness as a straightforward strategy to generate long-range networks of dispersed and interconnected multiwalled carbon nanotubes in polystyrene nanocomposites prepared by melt-blending strategies based on melt extrusion and injection moulding. Particularly, we assessed the effect of grafting the carbon nanotubes through free radical polymerisation to modulate the nanoscale interfacial interactions thereof, in comparison with pristine and carboxylated counterparts, in terms of the morphology and mechanical performance of the materials. Subsequently, we correlated the mechanical behaviour of the prepared nanocomposites with the dispersion degree of the different types of nanotubes used. In addition, we explored the nanoscale mechanism of mechanical energy dissipation by electron microscopy analysis at the fracture zones together with mechanical impact tests. In this sense, we observed that the type of nanoscale interfacial interaction among nanotubes and the polymer matrix is the main ruling factor in crack propagation after impact or tensile stress. Finally, we demonstrated for the first time that the supramolecular self-assembly of PS-grafted multiwalled carbon nanotubes in melt-blended PS nanocomposites represents a promising tool to enhance the elastic modulus, thus opening the possibility to design systems with improved properties, using industrially attractive processes.