In situ synthesis of polyisoprene/grafted single-walled carbon nanotube composites

Polyisoprene (PIp)/single-walled carbon nanotube (SWNT) composites were prepared by grafting PIp from the surface of SWNTs via in situ anionic polymerization using sec-butyllithium as an initiator. The anionic initiator molecules were covalently attached to the SWNTs to form SWNTs-bearing carbanions, as confirmed by Fourier transform infrared analysis and Raman spectra. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) were used to image the PIp-g-SWNT composites; the results show a relatively uniform polymer phase present on the surface of individual, debundled nanotubes. The carbanions on the SWNT surface help separate the nanotubes in solution and lead to the development of homogeneous PIp rubber composites with well-dispersed nanotubes. Compared with pure PIp, the PIp/SWNT nanocomposites showed a significant improvement in thermal properties.