THE THERMAL CHARACTERIZATION AND RHEOLOGY BEHAVIOR OF PP/MWNTs NANOCOMPOSITES

Nanocomposites based on polypropylene (PP) and multi-walled carbon nanotube (MWNTs) were manufactured by melt blending.Thermal gravimetric analysis (TGA) showed that carbon nanotubes significantly enhanced the thermal stability of polypropylene in nitrogen.The temperature of onset decomposition was 44 K higher than that of neat PP for nanocomposites with 3 wt% of MWNTs loaded.The effect of MWNTs on the crystallization and melting behavior of polypropylene was not observed.Rheological behavior of PP/MWNTs nanocomposites showed that storage modulus (G′) and loss modulus (G″) increased with increasing nanotube content.At low frequency,the steady shear viscosity of nanocomposites with 1 wt% of MWNTs was minimal and that of the sample with 5 wt% nanotube was maximal.Shear thinning tendency increased with increasing frequency .The volume resistivity and surface resistivity of nanocomposite with 5 wt% MWNTs were 9 and 4 order of magnitude,respectively lower than those of the neat PP.It shows that the electrical conductivity can be improved obviously by incorporating a little MWNTs.