| Carbon black is one of the most important black pigment materials. It is widely used inprinting ink, coating, dyeing and printing of fibers and the other fields. Because of its specialmicrostructure, particle configuration and surface behavior, carbon black is easy toconglomeration and hard to stable dispersion while using, especially in aqueous system,which limits the scope of application of carbon black. As the society enhances environmentprotection problems ceaselessly, more and more attention pays to the study on aqueous carbonblack dispersion. The study on aqueous carbon black dispersion is one of hot spot of carbonblack dispersion.Firstly, aqueous carbon black dispersions were prepared by direct dispersing method.The influence factors of the dispersive stability of carbon black dispersions such as kinds ofdispersants, the amount of dispersants, dispersing method (including rotating dispersion,shearing dispersion, milling dispersion and ultrasonic dispersion), pH value of dispersion, theconcentration of NaCl and the concentration of carbon black were discussed. The resultsshowed that anionic dispersant with small molecular weight could disperse carbon blackparticles effectively, and sodium methylenedinaphthalene disulphonate was the most effectivedispersant. Among the polymer dispersants, sodium alginate was the most effective dispersant.The mix dispersants (the mass ratio of sodium methylenedinaphthalene disulphonate andpoly(vinyl pyrrolidone was1:1) had excellent dispersive stability to carbon black dispersions.Comparing the dispersive stability of four dispersing methods on aqueous carbon blackdispersions, milling dispersion was more effective than shearing dispersion, ultrasonicdispersion and rotating dispersion. The excellent dispersive stability of carbon blackdispersions were obtained by two-phase milling dispersion in shorter dealing time. Theoptimal conditions for the preparation of aqueous carbon black dispersions were: the amountof mix dispersants (the mass ratio of sodium methylenedinaphthalene disulphonate andpoly(vinyl pyrrolidone was1:1) was7.5%, the concentration of carbon black was30%, thepH value of dispersion was8, the milling speed was250r/min, milling5h with0.50mm ofzirconium ball diameter and4h with0.20mm of zirconium ball diameter. Secondly, the surface morphology, particle diameter, dispersive stability, Zeta potentialand thermal stability of carbon black in aqueous carbon black dispersions were characterizedand analysed by scanning electron microscopy, Zeta potential and particle diameter analyzer,thermogravimetric analysis. And the centrifugal stability, temperature stability and storestability of aqueous carbon black dispersions were studied. The results showed that the carbonblack particles from carbon black dispersions were smaller diameter particles and dispersed.the diameter distribution of carbon black particles from carbon black dispersions wasrelatively narrow, and the average diameter was85.0nm. The Zeta potential of carbon blackfrom carbon black dispersions was-32.5mV, and the carbon black particles had lower thermalstability after being dispersed. The prepared aqueous carbon black dispersions had preferablycentrifugal stability, temperature stability and store stability. |
