Dispersion of Barium Ferrite Particles for Slip Casting in Magnetic Field

2006 ◽  
Vol 317-318 ◽  
pp. 143-146 ◽  
Author(s):  
Jing Long Li ◽  
Saburo Sano ◽  
Akihiro Tsuzuki ◽  
Akihiro Gotou ◽  
Yasuo Shibasaki ◽  
...  

Water-based slurries containing barium ferrite particles have been prepared and slip cast in magnetic field. This paper presents the characteristics of the suspensions in terms of Iso-Electric Points (IEP) and zeta potential that were evaluated through pH titration and polymer adsorption. Both enlarging the specific surface area of particles by planetary milling and adjusting the pH to low value apparently increase the zeta potentials. Stable slurry was obtained by adding polyethylene glycol (PEG) into the suspension at pH = 2 ~ 3.5. The steric repulsion plays key role in dispersion and PEG films served as insulative layers and mechanically kept particles from contact each other. The barium ferrite particles formed many stacks of plates during slip casting, which either aligned randomly without magnetic field applied or regularly aligned to form textured structure when magnetic field was applied.

2012 ◽  
Vol 502 ◽  
pp. 208-211 ◽  
Author(s):  
Qiang Cao ◽  
Sheng Hua Lv ◽  
Di Li

A novel amphoteric polycarboxylate superplasticizer (APCs) was prepared by solution copolymerization from acrylic acid (AA), allyl polyethylene glycol (APEG), diallyldimethyl ammonium chloride (DMDAAC). Effects of DMDAAC dosage and monomers ratio on performance of APCs were investigated by tested of zeta potential of cement particles and adsorption on cement. Results indicated that introducing of cationic monomer can increase the saturation adsorption amount and dispersibility of APCS. When the molar ratio of AA and APEG and DMDAAC is 5:1:0.5, the dispersibility of APcs has the best adsorptivity and disersibility. The synergistic effects of Zeta potential and steric repulsion of the cement particles surface is the main mechanism for dispersion.


2011 ◽  
Vol 306-307 ◽  
pp. 1688-1692 ◽  
Author(s):  
Na Sun ◽  
Jian Jian Qin ◽  
Wen Juan Guo ◽  
Jin Zhang ◽  
Mei Shan Pei ◽  
...  

A novel amphoteric polycarboxylic acid-based superplasticizer (APC) was prepared by solution copolymerization from maleic anhydride (MA), allyl polyethylene glycol (APEG) and dimethyl diallyl ammonium chloride(DADMAC). The cationic monomer DADMAC was introduced for improving the performances of sulphoaluminate cement (SAC) with APC. The condition on preparation of APC was determined by the orthogonal experiment. The flow of paste and mortar were alao assessed. Results indicated that APC could improve the fluidity of paste and motar with APC. Zeta potential measurements indicate steric repulsion between the cement particles carrying adsorbed polymer molecules is the main mechanism for dispersion.


Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1185
Author(s):  
Rosario Mare ◽  
Huining Da ◽  
Massimo Fresta ◽  
Donato Cosco ◽  
Vibhudutta Awasthi

Polyethylene glycol (PEG)-phospholipids in long-circulating liposomes cause non-specific immune reactions; mainly attributable to negatively-charged phosphoryl s at the interface of PEG and phospholipid. We investigated a novel lipopolymer, by which a superhydrophilic polymer (SHP) is conjugated to a non-phospholipid N1-(2-aminoethyl)-N4-hexadecyl-2-tetradecylsuccinamide (HDAS). The modification of preformed liposomes HDAS-SHP, HDAS-PEG2000, and DSPE-PEG2000 were performed by post-insertion techniques. The efficiency of post-insertion and desorption rates, from the liposome surface, were determined. HDAS-SHP micelles showed highly positive zeta potential (+28.4 mV); zeta potentials of DSPE-PEG2000 and HDAS-PEG2000 micelles were −34.4 mV, and −3.7 mV, respectively. Critical micelle concentration predicted amphiphilicity of HDAS-SHP (CMC 2.58 µM) as close to that of DSPE-PEG2000 (CMC 2.44 µM). Both HDAS-SHP and HDAS-PEG2000 post-inserted with comparable efficiency (79%, and 73%, respectively), but noticeably lower than DSPE-PEG2000 (90%). The desorption rate of HDAS-SHP was close to that of DSPE-PEG2000 (0.53%/h, and 0.45%/h, respectively); the desorption rate for HDAS-PEG2000 was slightly more at 0.67%/h. Compared to plain liposomes, both HDAS-SHP- and DSPE-PEG2000-liposomes showed significant leakage of encapsulated Na-fluorescein isothiocyanate (FITC) upon incubation with serum. At the same time, both modified liposomes were found to suppress serum levels of the complement proteins, Bb and C4d. We infer that HDAS-SHP is a viable alternative to commonly-used PEG-phospholipid derivatives for stealth purposes.


2011 ◽  
Vol 484 ◽  
pp. 70-74
Author(s):  
Jun Bin Wu ◽  
Xiang Xin Xue ◽  
Tao Jiang ◽  
Qing Zhang

With boron-rich slag, silica fume, bauxite chalmette and carbon black as starting materials, α-sialon/AlN/BN powder was prepared by carbothermal reduction-nitridation. The powder was attrition milled to submicron size and suspended in water. The effects of yttrium oxide as a sintering aid, pH, and addition of deflocculant on the suspensions were studied. Optimum slip casting properties, i.e. lowest viscosity values, the highest absolute zeta potential values, the smallest floc size and sediment volume were found at pH=10 for the powder. The suspensions were used to slip cast discs which were sintered in a high purity nitrogen atmosphere at 1700 °C for 2 h. The strength was about 230 MPa, the toughness 3.6 MPa•m1/2 and the hardness about 13.8 GPa.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Hou ◽  
Ming Han ◽  
Jinxun Wang

AbstractThis work investigates the effect of the surface charges of oil droplets and carbonate rocks in brine and in surfactant solutions on oil production. The influences of the cations in brine and the surfactant types on the zeta-potentials of both oil droplets and carbonate rock particles are studied. It is found that the addition of anionic and cationic surfactants in brine result in both negative or positive zeta-potentials of rock particles and oil droplets respectively, while the zwitterionic surfactant induces a positive charge on rock particles and a negative charge on oil droplets. Micromodels with a CaCO3 nanocrystal layer coated on the flow channels were used in the oil displacement tests. The results show that when the oil-water interfacial tension (IFT) was at 10−1 mN/m, the injection of an anionic surfactant (SDS-R1) solution achieved 21.0% incremental oil recovery, higher than the 12.6% increment by the injection of a zwitterionic surfactant (SB-A2) solution. When the IFT was lowered to 10−3 mM/m, the injection of anionic/non-ionic surfactant SMAN-l1 solution with higher absolute zeta potential value (ζoil + ζrock) of 34 mV has achieved higher incremental oil recovery (39.4%) than the application of an anionic/cationic surfactant SMAC-l1 solution with a lower absolute zeta-potential value of 22 mV (30.6%). This indicates that the same charge of rocks and oil droplets improves the transportation of charged oil/water emulsion in the porous media. This work reveals that the surface charge in surfactant flooding plays an important role in addition to the oil/water interfacial tension reduction and the rock wettability alteration.


2000 ◽  
Vol 47 (9) ◽  
pp. 1010-1014 ◽  
Author(s):  
Tohru S. Suzuki ◽  
Hideyuki Ohtsuka ◽  
Yoshio Sakka ◽  
Keijiro Hiraga ◽  
Koichi Kitazawa

2005 ◽  
Vol 284-286 ◽  
pp. 489-492 ◽  
Author(s):  
Hirotaka Maeda ◽  
Toshihiro Kasuga ◽  
Masayuki Nogami

Hydroxycarbonate apatite (HCA), which formed on a poly(lactic acid) (PLA) composite membrane containing vaterite or calcium chloride after soaking in simulated body fluid, was examined to clarify the importance of the ceramic phases in the composites. FT-IR spectra showed that the ratio of CO3/PO4 in the infrared adsorption bands of HCA formed on the PLA composite containing vaterite was much larger than that of HCA formed on the PLA composite containing calcium chloride. Substitution of carbonate ion in hydroxyapatite is believed to be strongly influenced by ceramic phases in the composites. The zeta potentials of HCA formed on the PLA composite containing vaterite or calcium chloride was -6 mV or -17 mV, respectively. The zeta potential may be influenced by the amount of carbonate ion in hydroxyapatite.


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