(703a) Effect of Carbon Nanotube Concentration and Functional Group Length On the Properties of Melt Extruded Polypropylene Nanocomposites

The chemistry and concentration of the nanotubes have a significant effect on the thermal stability and mechanical properties of the final melt extruded nanocomposite. We report the influence of functional group length and nanotube concentration on the properties of polypropylene (PP) nanocomposites containing SWNTs, or functionalized SWNTs. Functionalization can improve dispersion by increasing steric hindrance between tubes and improving interfacial interactions between the SWNTs and polymer chains. However, functionalization also deteriorates SWNT properties and introduces impurities that can catalyze polymer degradation. The nanotubes and PP were mixed by spray mixing followed by melt extrusion. The level of nanotube dispersion and nanotube-polymer interaction were evaluated by a combination of microscopy, rheology, Raman spectroscopy, thermal and mechanical analyses.