Effect of radical grafting of tetramethylpentadecane and polypropylene on carbon nanotubes' dispersibility in various solvents and polypropylene matrix

Multiwalled carbon nanotubes (MWCNTs) have been functionalized by tetramethylpentadecane (TMP), 1-dodecanethiol (DT) and polypropylene (PP) through radical addition onto MWCNTs' surface using dicumyl peroxide as hydrogen abstractor. Surface functionalized MWCNTs were characterized by Raman, IR spectroscopy, elementary analysis (EA) and thermogravimetric analysis (TGA). We studied the effect of temperature, peroxide concentration and solvent on TMP grafting densities and it was found that this surface treatment lead to a fair solubility in various solvents. TMP-functionalized MWCNTs were also imaged by transmission electronic microscopy showing single long functionalized MWCNTs distinct from the starting pristine bundles. For the first time, PP was then grafted onto MWCNTs through a radical grafting reaction. However, scanning electronic microscopy images of PP-functionalized MWCNTs/PP composites did not show a significant improvement in MWCNTs dispersion within the PP matrix.