Effect of Nanotube Length on Rheological Characteristics of Polystyrene/Multi-walled Carbon Nanotube Nanocomposites Prepared by Latex Technology

Polystyrene (PS)/multi-walled carbon nanotube (MWCNT) nanocomposites were prepared via latex technology and the effect of nanotube length on rheological properties were investigated. Monodisperse PS particle was synthesized by the emulsifier-free emulsion polymerization and two types of MWCNTs were used after surface modification to improve dispersion state and to remove impurities. Final nanocomposites were prepared by the freeze-drying process after dispersing the PS particles and the surface-modified MWCNTs in a ultrasonic bath. The effects of MWCNT content and nanotube length on rheological properties were evaluated by imposing the small-amplitude oscillatory shear flow. The PS/MWCNT nanocomposites showed that rheological properties were enhanced as the amount and length of MWCNT increased. It is speculated that the rheological characteristics of nanocomposites change from liquid-like to solid-like as the MWCNT amount increases, and the critical concentration to achieve network structure decreases as the nanotube length increases.