Na4EDTA and EDTA were adopted as new additives to intensify the seeded precipitation process of sodium aluminate solution. The effects of the two additives at certain concentrations on the seeded precipitation rate of...Na4EDTA and EDTA were adopted as new additives to intensify the seeded precipitation process of sodium aluminate solution. The effects of the two additives at certain concentrations on the seeded precipitation rate of sodium aluminate solution, particle size distribution (PSD) and morphology of precipitated gibbsite were investigated using titration method, particle size analyzer and scanning electron microscope (SEM), respectively. The results show that the two additives can accelerate the seeded precipitation rate of sodium aluminate solution. At relatively high concentration, the facilitative effect of EDTA on sodium aluminate solution is more obvious than that of Na4EDTA. EDTA makes gibbsite particles thinner than Na4EDTA. The Na+ and H+ result in the different effects on the seeded precipitation rate of sodium aluminate solution in spite of the same EDTA anion in the two additives.展开更多
Poly(methyl methacrylate)/poly(N-isopropylacrylamide) (PMMA/PNIPAM) core-shell particles were synthesized by seeded precipitation polymerization of N-isopropylacrylamide (NIPAM) in the presence of PMMA seed pa...Poly(methyl methacrylate)/poly(N-isopropylacrylamide) (PMMA/PNIPAM) core-shell particles were synthesized by seeded precipitation polymerization of N-isopropylacrylamide (NIPAM) in the presence of PMMA seed particles. The anionic potassium persulfate was used as initiator, and acrylic acid as functional comonomer. It was shown that the weight ratio of the PNIPAM shell to the PMMA core can be greatly increased through continuous addition of NIPAM monomer at a relatively slow rate. PMMA/PNIPAM particles with different shell thickness were obtained by varying the amount of charged NIPAM monomers. These particles exhibited unique nonspherical core-shell morphology. PMMA core was partially coated by dense hair-like or antler-like PNIPAM shell depending on the shell thickness. The measurement of these particles' zeta potential at different temperatures showed that the absolute value of zeta potential unusually decreased as the particle size decreased with temperature.展开更多
基金Project(20476107) supported by the National Natural Science Foundation of ChinaProject(2005CB623702) supported by the National Basic Research Program of China
文摘Na4EDTA and EDTA were adopted as new additives to intensify the seeded precipitation process of sodium aluminate solution. The effects of the two additives at certain concentrations on the seeded precipitation rate of sodium aluminate solution, particle size distribution (PSD) and morphology of precipitated gibbsite were investigated using titration method, particle size analyzer and scanning electron microscope (SEM), respectively. The results show that the two additives can accelerate the seeded precipitation rate of sodium aluminate solution. At relatively high concentration, the facilitative effect of EDTA on sodium aluminate solution is more obvious than that of Na4EDTA. EDTA makes gibbsite particles thinner than Na4EDTA. The Na+ and H+ result in the different effects on the seeded precipitation rate of sodium aluminate solution in spite of the same EDTA anion in the two additives.
基金financially supported by the National Natural Science Foundation of China(No.50943028)the Program for Liaoning Excellent Talents in Universities(No.LJQ2011037)
文摘Poly(methyl methacrylate)/poly(N-isopropylacrylamide) (PMMA/PNIPAM) core-shell particles were synthesized by seeded precipitation polymerization of N-isopropylacrylamide (NIPAM) in the presence of PMMA seed particles. The anionic potassium persulfate was used as initiator, and acrylic acid as functional comonomer. It was shown that the weight ratio of the PNIPAM shell to the PMMA core can be greatly increased through continuous addition of NIPAM monomer at a relatively slow rate. PMMA/PNIPAM particles with different shell thickness were obtained by varying the amount of charged NIPAM monomers. These particles exhibited unique nonspherical core-shell morphology. PMMA core was partially coated by dense hair-like or antler-like PNIPAM shell depending on the shell thickness. The measurement of these particles' zeta potential at different temperatures showed that the absolute value of zeta potential unusually decreased as the particle size decreased with temperature.