Journal of Applied Polymer Science, Vol.98, No.3, 1325-1338, 2005
Impure carbon nanotubes as reinforcements for acrylated epoxidized soy oil composites
Stable dispersions of impure multiwall carbon nanotubes (multiwall carbon nanotubes and carbon soot) in an acrylated epoxidized soy oil (AESO) based thermosetting resin were obtained by mechanical stirring. The required stirring time increased with an increasing amount of carbon nanotubes. Thermogravimetric analysis of the polymerized samples showed some loss of multiwall carbon nanotubes due to sedimentation. The mechanical properties of the polymerized samples improved significantly (the modulus increased by 30%) for 0.28 wt % dispersed multiwall carbon nanotubes. Higher multiwall carbon nanotube loads resulted in significant aggregation during polymerization. The mechanical properties were compared with existing models for nanocomposites. Wide-angle X-ray scattering, optical microscopy, and transmission electron microscopy demonstrated the formation of aggregates at higher multiwall carbon nanotube loads, which reversed the potential for mechanical improvement. Because of the stability of the original dispersion, the aggregates were believed to form during polymerization. This aggregation was magnified by the carbon soot, so only small amounts of impure multiwall carbon nanotubes could be used as reinforcements. Transmission electron micrographs showed good adhesion of the polymer matrix to the nanotubes upon the rupture of the polymer matrix. AESO was believed to act as a solubilizing surfactant, in line with previously published results. (c) 2005 Wiley Periodicals, Inc.