Application of cryomilling to enhance material properties of carbon nanotube reinforced chitosan nanocomposites

Abstract Cryomilled multiwall carbon nanotube (MWCNT) reinforced chitosan nanocomposites having improved conductivity have been prepared by solution casting method. The MWCNTs were crushed to smaller particles via cryomilling, which was effective in cleaving the nanotubes regularly as well as in reducing the entanglements and agglomeration. The cryomilled CNTs were chemically oxidized by acid and base methods, where basic oxidation generated high graphitic structure. The cryomilled and oxidized CNTs were characterized by XRD, Raman spectroscopy, FTIR and SEM. The conductivity of the nanocomposites was improved by cryomilling and it was further improved by chemical oxidation. Base oxidized cryomilled CNT/chitosan nanocomposites showed large improvement in conductivity compared to all other nanocomposites having 1 wt.% CNT content. Thermal stability and tensile properties of the CNT/chitosan nanocomposites also have been improved significantly by the incorporation of acid and base oxidized cryomilled CNTs. SEM picture of the fractured surface and FTIR showed nano-level dispersion of the functionalized CNTs and good chemical interaction between chitosan and CNTs respectively.