Effect of Poly(Vinyl Pyrrolidone) on Dispersing Carbon Black Particles

Abstract

The effects of poly (vinyl pyrrolidone)(PVP) on dispersing carbon black (CB) particles were investigated by measuring Z-average particle size, Zeta potential and centrifugal stability of CB dispersions. Addition of PVP in a dispersing medium significantly reduces the size of suspended CB particles, especially in water. The dispersing efficiency of PVP was found to have been enhanced by adding an anionic surfactant, sodium methylenedinaphthalene disulphonate (NNO) in the aqueous media. The particle size of CB dispersed with PVP and NNO was 175.7 nm, significantly smaller than that dispersed with PVP and sodium dodecyl sulfate (SDS). The performance of PVP-encapsulated CB particles and that of PVP-adsorbed CB particles were also compared. The particle size and Zeta potential of PVP-encapsulated CB particles were similar to those of PVP-adsorbed CB particles using ultrasonic method, but the centrifugal stability of PVP-encapsulated CB dispersions was significantly improved. The relative absorbency of PVP/CB dispersions was increased from 42.0% to 63.7%. However, the PVP-encapsulated layer can be destroyed by prolonged ultrasonic treatment because the ultrasound over a long period of time can not only break up the flocculation bridge in the crosslinking matrix of PVP, but also flake off the PVP shells on the surface of CB particles.