Emulsion Prepared By Two-Stage Ceramic Membrane Jet-Flow Emulsification And Preparation Of Porous Ceramic

The two-stage membrane jet-flow emulsification was a novel method for preparation of monodispersed emulsion. In this thesis, an emulsion template was prepared by the two-stage membrane jet-flow emulsification. A regular ceramic material of TiO2 was prepared using the template of uniform emulsion.The monodispersed isooctane/formamide emulsions were prepared by an integrated ceramic emulsification apparatus. A ZrO2 membrane with a pore size of 0.2μm was used in first stage and anα-Al2O3 with a pore size of 1.6μm was used in the second stage. The continuous phase was the formamide and the dispersed phase was the isooctane. The poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) was used as surfactant in this process . The flux of dispersed phase increased with the increase of pore size of membrane used in the second stage. The droplet size of emulsions do not increased with the increase of pore size of membrane used in the second stage. The appropriate membrane using in the second stage emulsification was membrane with the pore size of 1.6μm. The droplet size of emulsions increased slowly with the increase of transmembrane pressure. The emulsion prepared with the higher transmembrane pressure show better stability and monodispersity than the one prepared with low transmembrane pressure. The emulsions prepared by the two-stage membrane jet-flow emulsification showed excellent stability and monodispersity in 16 hours.A calculation method of sedimentation time in the preparing high concentration emulsion by centrifugation was introduced. The emulsion with a droplet size of 1.8μm was prepared by the two-stage membrane jet-flow emulsification. Sedimentation velocity of the droplet was expressed as the equation u_r=2.81×10^-9×ω2×e(-2.571×10^-8×ω²t).The theoretic sedimentation time centrifugation time was expressed as the equation . The droplet size of emulsions increased slowly with the increase of the centrifugation time. The coefficient of dispersionαof the emulsions was increased with the increase of the centrifugation time. The coefficient of dispersionαof emulsions was below 0.35 in the whole process. In a high centrifugation speed, the emulsions showed excellent stability and monodispersity within calculated value.