Abstract

The present work is focused on the synthesis and preparation of high impact polystyrene (HIPS)/Multiwalled carbon nanotubes (MWCNT) composites and their characterization and analysis by transmission and scanning electron microscopy (TEM and SEM). Specifically, the analysis consists in evaluate the effect of volume fraction of elastomeric phase (Φ) in the HIPS on the threshold percolation concentration (Pc). The MWCNT were modified using a plasma reactor in presence of styrene, while the HIPS were synthesized in a batch reactor by mean of the mass-suspension technique. HIPS and MWCNT modified were mixed in melt at different concentrations of MWCNT. Finally, all materials were analyzed by SEM and TEM. A polystyrene (PS) thin layer (2-4 nm) on the MWCNT was found by TEM. On the other hand, the HIPS morphology salami type was observed for all HIPS synthesized with an average particle diameter (Dp) from 1.4 to 1.8 μm and a Φ from 0.35 to 0.40. Respect to the 3D continuous network of MWCNT builds (percolation threshold) was found at 3 and 2 wt-% of MWCNT. Decrease in the Pc was attributed to the increment in the Φ. That is, the rubber particles act as big holes into the three-dimensional continuous network, and if the amount of particles in volume increases the MWCNT concentration necessary to form the network decreases. Finally, the thin layer of PS on nanotubes surface plays an important role, it avoids the agglomeration of MWCNT´s and allows a good dispersion of the MWCNT in the PS phase.