Fabrication of hybrid nanocomposites with polystyrene and multiwalled carbon nanotubes with well-defined polystyrene via multiple atom transfer radical polymerization

The PS-grafted multiwalled carbon nanotubes (MWNTs) were produced by the bromo-ended PS (PS-Br) and pristine MWNTs in 1,2-dichlorobenzene at 110 °C for 72 h via atom transfer radical polymerization (ATRP). Bromo-ended PS (PS-Br) used as an initiator for the functionalization of MWNTs was synthesized with styrene by ATRP conditions using CuBr and N,N,N′,N′,N″-pentamethyldiethylenetriamine as catalyst. The PS-grafted MWNTs were fully characterized by 1H-NMR, FT-IR, DSC, TGA, and SEM. The PS-grafted MWNTs were found to be highly soluble in a variety of organic solvents. The PS was chemically attached to the surfaces of MWNTs via ATRP approach, and the grafting amount of PS was 40-90%. From TGA and DSC measurements, the PS-grafted MWNTs were decomposed at lower temperature compared to that of PS-Br, and the functionalization of MWNTs increased the glass-transition temperature (Tg) of the grafted PS. The PS/PS-grafted MWNTs nanocomposites were prepared with PS and PS-grafted MWNTs by solution mixing in dimethylformamide (DMF). The resulting nanocomposites were found to be the homogeneous dispersion of PS-grafted MWNTs in PS matrix via aromatic (π-π) interactions between PS and PS-grafted MWNTs as determined by SEM and TEM.