Organic modification of nano-SiO2 particles in supercritical CO2
نویسندگان
چکیده
Organic modification of nano-SiO2 particles was performed with supercritical CO2 as solvent and a titanate coupling reagent NDZ-201 as the modification reagent. The surface of the nano-SiO2 particles was changed after modification by the titanate coupling reagent from hydrophilic to hydrophobic. IR and thermo-gravimetric analyses indicate that the interaction between the titanate coupling reagent and the particle surface is mainly through chemical bonding. The influence of the apparent concentration of the titanate coupling reagent on the modification at 60 ◦C and 20.0 MPa was investigated, in which the apparent concentration is the weight percent of the titanate coupling reagent added in the supercritical solvent. The quantity of the titanate coupling reagent reacted on the particle surface reaches a maximum of 19.81× 10−7 mol/m2, i.e. 1.19 molecule titanate coupling reagent/nm2, when the apparent concentration of titanate coupling reagent is 0.6% ( ©
منابع مشابه
Organic modification of ultrafine particles using carbon dioxide as the solvent
An organic modification of the surface of titanium dioxide particles precoated with SiO2 and Al2O3 films in a CO2 medium is performed, where CO2 of different phases is used as the solvent and a titanate coupling reagent (CH3)2CHOTi(OP(O)(OH)OP(O)(OC8H17)2)3 is the modification reagent. The results are compared with the modification carried out in a conventional organic solvent. The interaction ...
متن کاملDrug Nano-Particles Formation by Supercritical Rapid Expansion Method; Operational Condition Effects Investigation
Dissolution pressure and nozzle temperature effects on particle size and distribution were investigated for RESS (Rapid Expansion of Supercritical Solution) process. Supercritical CO2 was used as solvent and Ibuprofen was applied as the model component in all runs. The resulting Ibuprofen nano-particles (about 50 nm in optimized runs) were analyzed by SEM and laser diffraction pa...
متن کاملSurface modification of ZnO nano-particles with Trimetoxyvinyl Silane and Oleic Acid and studying their dispersion in organic media
Zinc oxide nano-particles with the average diameter of about 25 nm were modified with different mole ratios of trimetoxyvinyl silane (TMVS) and oleic acid, as coupling agents, in order to modify their surface properties and render them more hydrophobic. Then, dispersibility of the surface modified nano-particles was examined in some monomers with different levels of hydrophobicity, including me...
متن کاملSurface modification of ZnO nano-particles with Trimetoxyvinyl Silane and Oleic Acid and studying their dispersion in organic media
Zinc oxide nano-particles with the average diameter of about 25 nm were modified with different mole ratios of trimetoxyvinyl silane (TMVS) and oleic acid, as coupling agents, in order to modify their surface properties and render them more hydrophobic. Then, dispersibility of the surface modified nano-particles was examined in some monomers with different levels of hydrophobicity, including me...
متن کاملFabrication of Metal Nanoparticles by Pulsed Laser Ablation in Supercritical CO2
Fabrication of nano-structured materials has been developed by performing pulsed laser ablation of copper, gold, and silver plates in supercritical CO2. The metal nano-structured particles were successfully generated with allowing the selective generation of clusters. Laser ablation was performed with an excitation wavelength of 532 nm. On the basis of the experimental result, both surface of a...
متن کامل