Dispersion of multiwall carbon nanotubes in blends of polypropylene and acrylonitrile butadiene styrene

State of dispersion of purified multiwall carbon nanotubes (p-MWNT) in the presence of neutralized MWNT (n-MWNT) in aqueous solution was assessed through UV-Visible spectroscopy, dynamic light scattering measurements, and solution experiments. Raman spectroscopic analysis revealed that debundling of p-MWNT in the presence of n-MWNT in aqueous solution was persistent even in the solid mixture, which was supported by transmission electron microscopic analysis. The proposed mechanism behind the improved dispersion of p-MWNT in the presence of n-MWNT in aqueous solution has been based on the electrostatic charge repulsion between negatively charged n-MWNT. The state of dispersion of p-MWNT in the presence of n-MWNT in 45/55 polypropylene/acrylonitrile butadiene styrene (PP/ABS) blends was assessed through Raman spectroscopic analysis, bulk electrical conductivity measurements, solution experiment, and crystallization studies. Raman spectroscopic analysis indicated that the state of dispersion of MWNT was improved with increasing n-MWNT content of the mixture. This strategy led to a remarkable increase in the bulk electrical conductivity of 45/55 PP/ABS blends at 3 wt% MWNT content and was strongly dependent on the concentration of n-MWNT in the mixture. Differential scanning calorimetric measurements along with solution experiments revealed the subsequent migration of MWNT from the PP phase to the ABS phase in the blends during melt-mixing in the presence of higher fraction of n-MWNT. POLYM. ENG. SCI., 51:1891-1905, 2011. (C) 2011 Society of Plastics Engineers