Dispersion and Rheology of Multiwalled Carbon Nanotubes in Unsaturated Polyester Resin

Dispersions of multiwalled carbon nanotubes (MWNT) in unsaturated polyester resin (UPR) were studied by rheology and optical microscopy. The experimentally determined percolation threshold of 0.097 vol % was very close to the theoretical value of 0.085 vol % expected for individually dispersed MWNT with an average aspect ratio of 590. Rheological analysis showed that the dispersions formed an open network with a fractal dimension of 1.28. The results were compared with single-walled carbon nanotubes (SWNT) and polystyrene (PS)-modified MWNT (MWNT-PS). The SWNT formed stronger networks than MWNT, but the MWNT-PS networks were weaker than unmodified MWNT.