Peculiarities of Raman spectra of polyurethane/carbon nanotube composite

We present a detailed analysis of the Raman spectra of polyurethane (PU)/single wall carbon nanotube (SWCNT) composites obtained at room temperature using 488 and 514.5 nm laser excitation. The spectra reveal a significant influence of the polymeric matrix on the carbon nanotube bundles. The nanocomposite Raman bands become broader and are shifted to higher frequencies in comparison to the corresponding bands of the pristine SWCNT bundles. Redistribution of intensity in the vicinity of a G-band and an increase of splitting of the radial breathing mode are also observed for the nanocomposites. Various spectral features of SWCNT clearly indicate the large interfacial interaction of the PU matrix and the SWCNT, possibly due to the π-π stacking between the PU chains and the SWCNT