Study On The Dispersity And Stability Of Graphite Aqueous Suspensions

The graphite dispersion was made in water with various surfactants and dispersants by ultrasonic dispersion. It will be useful for making the releasing agent at high temperature, and it can also gain the added-value of graphite. And the product would replace the importing ones. The dispersity and stability of the graphite aqueous suspensions was investigated with centrifugation, the violet visible spectrophotometer, the laser particle size analyzer and scanning electron microscopy (SEM). The following aspects of the production technique were carefully studied:1. The effects of surfactants, poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), sodium alginate (SA-Na) and poly(sodium acrylate) (PA-Na) on the suspension stability of graphite were investigated.2. The effects of dispersion techniques, disperse medium, PH and the concentration of sodium carboxymethyl cellulose (CMC) on the suspension stability of graphite were carried out.3. The effects of poly(vinyl alcohol) (PVA), poly(vinylpyrrolidone) (PVP), sodium alginate (SA-Na) and poly(sodium acrylate) (PA-Na), blended with sodium carboxymethyl cellulose (CMC) respectively, on the suspension stability of graphite were studied.The main important findings were as follows:1. The hydrophobic graphite flakes could be well dispersed by both anionic and nonionic surfactants. The stability of the graphite aqueous suspensions was improved with PVA or PVP due to the macromolecular entropic elasticity and osmotic pressure. The graphite aqueous suspensions were even much more stable than those of PVA and PVP when SA-Na or PA-Na was added due to the extra electrostatic repulsion.2. Graphite could be better dispersed by sand mill than by ultrasonic dispersion.