Organic modification of nano-SiO2 particles in supercritical CO2

2006 ◽  
Vol 37 (1) ◽  
pp. 125-130 ◽  
Author(s):  
Zhi-Wen Wang ◽  
Ting-Jie Wang ◽  
Zhan-Wen Wang ◽  
Yong Jin
Keyword(s):  
Supercritical Co2 ◽  
Organic Modification ◽  
Nano Sio2 ◽  
Sio2 Particles

scholarly journals Dispersion and deagglomerat1on of nano-SiO2 particles with a silane modification reagent in supercritical CO2

2007 ◽  
Vol 61 (3) ◽  
pp. 109-116
Author(s):  
Dusica Stojanovic ◽  
Goran Vukovic ◽  
Aleksandar Orlovic ◽  
Petar Uskokovic ◽  
Radoslav Aleksic ◽  
...  
Keyword(s):  
Conventional Method ◽  
Supercritical Co2 ◽  
Particle Surface ◽  
Comparison Method ◽  
The Other ◽  
Hydroxyl Groups ◽  
Nano Sio2 ◽  
Coupling Reagent ◽  
Silane Coupling ◽  
Sio2 Particles

The supercritical CO2 method was used in order to perform deagglomeration and improve the dispersion of nano-SiO2 particles. ?-Met-hacryloxypropyltrimethoxysilane was used as the surface modification reagent. The conventional method for coating nano-SiO2 particles was used as the comparison method. Considerable improvement of the dispersion and deagglomeration was found using supercritical CO2. Analysis of the TEM micrographs and DLS results showed the reduction of the average size of the agglomerates with the silane coupling reagent. Thermogravimetric analysis (TGA) showed that the particles treated in super?critical CO2 were more thermally stable than particles treated by conventional method. Encapsulation of several particles coated with the silane coupling reagent was observed in certain parts of the primary particles. A chemical reaction takes place between the modification reagent, MEMO silane, and active hydroxyl groups on the surface of the nano-SiO2 particles. A larger quantity of MEMO silane reacted using the con?ventional method instead of the supercritical method. On the other hand, the reacted silane molecules were better arranged around the particle surface in the supercritical method because of the formation of covalent or self-assembled structures. Polycondensed structures were preferentially obtained in the conventional method. This was achieved by using supercritical CO2, which has a high solvating power such as organic solvents and physical properties (low viscosity, low surface tension and high diffusion coefficient) similar to gases on the other side. These properties enable the sufficient and uniform wettability of nano-SiO2 particle surfaces. These results are important for obtaining nanofillers with improved dispersion and polymer wettability. Such nanofillers can be used to obtain composite materials with considerably improved mechanical characteristics.

Largely improved toughness of PP/EPDM blends by adding nano-SiO2 particles

Polymer ◽  
2007 ◽  
Vol 48 (3) ◽  
pp. 860-869 ◽  
Author(s):  
Hong Yang ◽  
Xiaoqing Zhang ◽  
Cheng Qu ◽  
Bo Li ◽  
Lijuan Zhang ◽  
...  
Keyword(s):  
Nano Sio2 ◽  
Sio2 Particles

Double Sealing of Ultrasonic Micro-Arc Oxidation Coating on Pure Magnesium by Nano-SiO2 Particles and SiO2 Sol Sealing Agent

2014 ◽  
Vol 1030-1032 ◽  
pp. 48-51
Author(s):  
Wei Wei Sun ◽  
Mu Qin Li ◽  
Yan Gao ◽  
Jiang Liu
Keyword(s):  
Corrosion Resistance ◽  
Bone Growth ◽  
Corrosion Current ◽  
Pure Magnesium ◽  
Infrared Spectrometry ◽  
Nano Sio2 ◽  
Micro Arc Oxidation ◽  
Sio2 Particles ◽  
Si Content ◽  
Sealing Coating

A double sealing coating was prepared on ultrasonic micro-arc oxidized pure magnesium substrate by adding nano-SiO2 particles as additive in the plating solution and coating SiO2 sol as sealing agent. The bonding characters of SiO2 sol was analyzed by Fourier transformed infrared spectrometry (FTIR). The compositions and morphology of seal coating were characterized by energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM), respectively. The corrosion resistance of the micro-arc oxidized and the sealed pure magnesium substrate were studied. The results showed that the Si content increased gradually with the addition of nano-SiO2 particles and the SiO2 sol sealing. It was benefit to create bioactive MgSiO3, which promoted the bone growth. The double sealed pure magnesium had a self-corrosion potential shifted positively by 60mV as well as a self-corrosion current density decreased by a half in a 3.5wt% NaCl solution, showing good corrosion resistance.

Performance of Cement Systems with Nano-SiO2 Particles Produced by Using the Sol–Gel Method

2010 ◽  
Vol 2141 (1) ◽  
pp. 10-14 ◽  
Author(s):  
I. Flores ◽  
K. Sobolev ◽  
L. M. Torres-Martinez ◽  
E. L. Cuellar ◽  
P. L. Valdez ◽  
...  
Keyword(s):  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Nano Sio2 ◽  
Sio2 Particles

Teratogenic responses of zebrafish embryos to decabromodiphenyl ether (BDE-209) in the presence of nano-SiO2 particles

Chemosphere ◽  
2017 ◽  
Vol 178 ◽  
pp. 449-457 ◽  
Author(s):  
Shu-Ju Chao ◽  
Chin Pao Huang ◽  
Pei-Chung Chen ◽  
Chihpin Huang
Keyword(s):  
Zebrafish Embryos ◽  
Decabromodiphenyl Ether ◽  
Nano Sio2 ◽  
Sio2 Particles ◽  
Bde 209

Effects of Neutron Flux, Frequency and Temperature on the Dielectric Loss of Nano SiO2 Particles

Silicon ◽  
2016 ◽  
Vol 10 (2) ◽  
pp. 191-196 ◽  
Author(s):  
Elchin Huseynov ◽  
Adil Garibov ◽  
Ravan Mehdiyeva ◽  
Efsane Huseynova
Keyword(s):  
Dielectric Loss ◽  
Neutron Flux ◽  
Nano Sio2 ◽  
Sio2 Particles
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