Route to the Synthesis of Binder‐Free SWCNT Solids with Enhanced Mechanical Properties Available to Purchase

Binder‐free macroscopic single‐walled carbon nanotube (SWCNT) solids were prepared by the hot‐pressing and the spark plasma sintering (SPS) of purified SWCNTs at temperatures of 1000, 1400 and 1800°C under a pressure of 120 MPa. The effects of processing conditions of the SWCNT solids on mechanical properties and microstructures were investigated. The SPS method was useful to increase the Young’s modulus and fracture strength of the SWCNT solid with respect to the hot‐pressing method. The mechanical properties of the SWCNT solids prepared by SPS were always higher than those of the SWCNT solids prepared by hot‐pressing under the identical processing temperature. The maximum value for the average Young’s modulus and fracture strength were 25.1 GPa and 106.8 MPa, respectively. TEM observation revealed that the high temperature treatment has converted some part of the SWCNTs into graphite‐like materials and the rest of the SWCNTs remained buried into the above structure. The mechanical properties of the SWCNT solids were increased with the increasing processing temperature, reflecting probably the improvement of interfacial strength between SWCNTs and graphite‐like materials.