Polystyrene−single-wall carbon nanotube (PS−SWNT) nanocomposites were prepared by directly mixing aqueous suspensions of exfoliated SWNTs and PS latex particles. After freeze-drying and compression molding, homogeneous polymer films were obtained with well-dispersed carbon nanotubes, as evidenced by scanning electron microscopy imaging. The nanocomposite films display a low percolation threshold and high levels of electrical conductivity. Simultaneously, a considerable increase in the glass-transition temperature of PS is achieved, provided that a sufficient amount of low-molar-mass PS is present in the matrix material. It is suggested that a certain extent of molar mass segregation occurs in the samples, with shorter PS chains preferentially adsorbed onto the nanotube surface. The latter wetting mechanism is indispensable for obtaining favorable electrical and thermal properties.

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Electrically conductive composites consisting of carbon nanotubes (CNTs) in a poly(2,6-dimethyl-1,4-phenylene ether)/polystyrene (PPE/PS) blend are prepared by latex technology. The latter consists of 4 steps: preparation of an aqueous dispersion of CNTs, mixing with a polymer latex, solvent removal by freeze-drying and processing. In the first route, PPE/PS blend latexes are directly used to prepare nanocomposites by latex technology. The CNT/PPE/PS composites display an increased glass transition temperature compared to unfilled material and a percolation threshold as low as 0.3 wt% of CNTs. Secondly, CNT/PS masterbatches prepared by latex technology are mixed with PS/PPE blend pellets by extrusion. This approach constitutes a potential first step towards an industrially viable process.