Formation of Polymer-Carbon Nanotube Composites by Two-Step Supercritical Fluid Treatment

Abstract

An approach for polymer-carbon nanotube (CNT) composite preparation is proposed based on a two-step supercritical fluid treatment. The first step, rapid expansion of a suspension (RESS) of CNTs in supercritical carbon dioxide, is used to de-bundle CNTs in order to simplify their mixing with polymer in solution. The ability of RESS pre-treatment to de-bundle CNTs and to cause significant bulk volume expansion is demonstrated. The second step is the formation of polymer-CNT composite from solution via supercritical antisolvent (SAS) precipitation. SAS treatment allows avoiding CNT agglomeration during transition from a solution into solid state due to the high speed of phase transition. The combination of these two supercritical fluid methods allowed obtaining a polycarbonate-multiwalled carbon nanotube composite with tensile strength two times higher compared to the initial polymer and enhanced elasticity.

Functionalization of Carbon Nanotubes in Polystyrene and Properties of Their Composites: A Review

“…CNTs exhibit excellent optical, thermal, electrical, and mechanical properties, providing extensive prospects in nanocomposite materials [ 13 ], sensors [ 14 ], energy conversion and storage [ 15 ], transparent conductors [ 16 ], flexible electronics [ 17 ], electromagnetic shielding [ 18 ], and catalysts [ 19 ]. However, the strong van der Waals forces among CNTs result in the formation of bundles or larger agglomerates, making it challenging to disperse them in water, organic solvents, or polymer matrices, limiting their applications in various fields [ 20 , 21 ]. Similarly, achieving proper dispersion of CNTs in PS is a primary challenge in the study of CNTs/PS nanocomposites.…”