The effects of SN5040 and polyethylene glycol（PEG） individually and in combination on the dispersion stability of nano-TiO2 aqueous suspension were investigated by ultraviolet-visible absorption spectroscopy. The ad...The effects of SN5040 and polyethylene glycol（PEG） individually and in combination on the dispersion stability of nano-TiO2 aqueous suspension were investigated by ultraviolet-visible absorption spectroscopy. The adsorption mechanism of these dispersants was detected by zeta potential, isothermal absorption and FTIR analysis. It is found that SN5040 is superior for stabilizing nano-TiO2 in aqueous suspension to PEG in basic region, and the optimum mass fraction of SN5040 addition is 3%. In the case of NaCl addition, the optimum value increases with .the increase of NaCl concentration in the solution. When the mixture of SN5040 and PEG is employed, the antagonism appears preponderant. When SN5040 and PEG are added sequentially, the synergistic reaction takes place. The synergistic reaction can be attributed to the mechanism that PEG adsorption decreases the electronic repulsion between SN5040 molecules, which results in the increase of SN5040 adsorption density. PEG is adsorbed by the interaction with the pre-adsorbed SN5040 layer. Furthermore, the modified inner wall latex paint with well dispersed nano-YiO2 suspension is endowed with excellent ultraviolet absorption and antibacterial properties.展开更多
A novel technology of in-situ coating Al2O3 on the surface of H4TiO4 was developed to prevent the aggregation of nano-TiO2 powders and improve the dispersibility and thermal stability in the way of forming a uniform c...A novel technology of in-situ coating Al2O3 on the surface of H4TiO4 was developed to prevent the aggregation of nano-TiO2 powders and improve the dispersibility and thermal stability in the way of forming a uniform coating layer. The heterogeneous nucleation was conducted to prepare the precursor of nano-TiO2 and then Al2O3 was coated on the surface of precursor. The effects of Al2O3 in-situ coating on the properties of nano-TiO2 were investigated. The results show that H4 TiO4 can be dispersed well under alkaline condition （pH 8. 5） and the heterogeneous nucleation can be controlled easily. The optimized uniform coating layer is obtained by adding 5 % （mass fraction ） and 10% of Al2O3 and the aggregation of nano-TiO2 powders is effectively inhibited and the dispersibility is obviously improved. The crystal sizes of TiO2 powders are 12.3, 11.4 and 8. 7 nm after coating 0, 5% and 10% of Al2O3 respectively. Al2O3 on the surface of particulates in amorphous phase could increase the thermal stability of nano-partieles after calcined at 550℃.展开更多
基金Project(04GK2007) supported by Hunan Industrial Key Project of Science and Technology
文摘The effects of SN5040 and polyethylene glycol（PEG） individually and in combination on the dispersion stability of nano-TiO2 aqueous suspension were investigated by ultraviolet-visible absorption spectroscopy. The adsorption mechanism of these dispersants was detected by zeta potential, isothermal absorption and FTIR analysis. It is found that SN5040 is superior for stabilizing nano-TiO2 in aqueous suspension to PEG in basic region, and the optimum mass fraction of SN5040 addition is 3%. In the case of NaCl addition, the optimum value increases with .the increase of NaCl concentration in the solution. When the mixture of SN5040 and PEG is employed, the antagonism appears preponderant. When SN5040 and PEG are added sequentially, the synergistic reaction takes place. The synergistic reaction can be attributed to the mechanism that PEG adsorption decreases the electronic repulsion between SN5040 molecules, which results in the increase of SN5040 adsorption density. PEG is adsorbed by the interaction with the pre-adsorbed SN5040 layer. Furthermore, the modified inner wall latex paint with well dispersed nano-YiO2 suspension is endowed with excellent ultraviolet absorption and antibacterial properties.
文摘A novel technology of in-situ coating Al2O3 on the surface of H4TiO4 was developed to prevent the aggregation of nano-TiO2 powders and improve the dispersibility and thermal stability in the way of forming a uniform coating layer. The heterogeneous nucleation was conducted to prepare the precursor of nano-TiO2 and then Al2O3 was coated on the surface of precursor. The effects of Al2O3 in-situ coating on the properties of nano-TiO2 were investigated. The results show that H4 TiO4 can be dispersed well under alkaline condition （pH 8. 5） and the heterogeneous nucleation can be controlled easily. The optimized uniform coating layer is obtained by adding 5 % （mass fraction ） and 10% of Al2O3 and the aggregation of nano-TiO2 powders is effectively inhibited and the dispersibility is obviously improved. The crystal sizes of TiO2 powders are 12.3, 11.4 and 8. 7 nm after coating 0, 5% and 10% of Al2O3 respectively. Al2O3 on the surface of particulates in amorphous phase could increase the thermal stability of nano-partieles after calcined at 550℃.
