scholarly journals COLLOID-CHEMICAL PROPERTIES OF SILICONE SURFACTANTS USED IN THE SYNTHESIS OF POLYSTYRENE LATEXES

2016 ◽  
Vol 11 (4) ◽  
pp. 56-62 ◽  
Author(s):  
I. A. Gritskova ◽  
A. A. Amelichev ◽  
O. A. Satskevich ◽  
A. V. Shkolnikov ◽  
A. A. Ezhova ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Modern Science ◽  
Chemical Properties ◽  
Polymerization Process ◽  
Narrow Particle Size Distribution ◽  
Aggregative Stability ◽  
Polymeric Microspheres ◽  
Silicone Surfactants

The synthesis of polymeric suspensions with a narrow particle size distribution is an urgent problem in modern science. The resulting polymeric microspheres are applicable in various fields of chemistry, pharmaceuticals, biology and medicine. In particular, they can be used as carriers of bioligands to create diagnostic test systems. This article presents the results of a study on the colloid-chemical characteristics of water-insoluble fluorinated silicone surfactants and kinetics of the polymerization process in their presence. The results were compared with data from studies on the properties of surfactants of similar structure not containing fluorine atoms in their structure. Studying these substances’ rheology enabled to determine the most suitable surfactants for adsorption forming a strong interfacial layer during the formation of polymermonomer particles during the polymerisation. The ability of fluorinated silicone surfactants to form a stable polymeric slurry was proved during heterophase polymerization of vinyl monomers. The resulting polymeric suspensions were characterized by a narrow particle size distribution and high aggregative stability during the synthesis and in storage.

Green synthesis of submicron copper powder with narrow particle size distribution via a simple methanol thermal reduction

2021 ◽  
Author(s):  
Xiaoping Chen ◽  
Jiaqi Fu ◽  
Jiangang Li ◽  
Bohong Chen ◽  
Lei Yang ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Green Synthesis ◽  
Size Distribution ◽  
Copper Powder ◽  
Reduction Method ◽  
Particle Distribution ◽  
Thermal Reduction ◽  
Narrow Particle Size Distribution

In this work, submicron copper powder with narrow particle distribution was synthesized via a simple methanol thermal reduction method without using any surfactants. Smaller copper powder with narrower particle size...

Organosilicon Comb-Shaped Surfactants for the Synthesis of Polymer Suspensions with a Narrow Particle Size Distribution

2021 ◽  
Vol 63 (3) ◽  
pp. 209-217
Author(s):  
A. A. Ezhova ◽  
I. A. Gritskova ◽  
S. A. Gusev ◽  
S. A. Milenin ◽  
V. V. Gorodov ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Narrow Particle Size Distribution

scholarly journals Investigation of Microbial Contamination and Physicochemical Properties of Compounded Medications in Pharmacies

2020 ◽  
Vol 26 (1) ◽  
pp. 82-93
Author(s):  
Reihaneh Radmanesh ◽  
◽  
Mohsen Nabi Meybodi ◽  
Vahid Ramezani ◽  
Maryam Akrami ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Microbial Contamination ◽  
Raw Materials ◽  
Chemical Properties ◽  
Pharmaceutical Product ◽  
Physical And Chemical ◽  
Made In ◽  
And Chemical Properties

Aims: Any pharmaceutical product made in pharmacy, hospital or factory may be contaminated with microbes. This contamination can originate from raw materials or during production. Hence, it is important to study the physical and chemical properties and stability of compounded drugs. Methods & Materials: In this study, first a specific sample of prescribed medication was ordered from 63 pharmacies in Yazd, Iran. After collecting the samples, the amount of microbial contamination, viscosity and particle size distribution and their stability were investigated and their results were compared to the standard levels. Findings: Based on the results, 31.7% of the samples had discoloration and 23.8% showed creaming phenomenon. In terms of particle size distribution, 57.1% of the samples had a 20-40 μm particle size and 49.2% had a viscosity equal to 2500-3000 centipoise. Regarding stability, 12.6% of the samples underwnet phase change at 30-40°C. About of the amount of hydroquinone in samples, 35% had acceptable amount. In 23.8% of the samples, fungal infection was observed. Conclusion: Contrary to a popular belief that the compounded medicines produced in pharmacies have microbial contamination, the results of this study showed that the microbial contamination of these compounded medications is low.

scholarly journals Encapsulation of Menthol in Beeswax by a Supercritical Fluid Technique

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
Linjing Zhu ◽  
Hongqiao Lan ◽  
Bingjing He ◽  
Wei Hong ◽  
Jun Li
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Flow Rate ◽  
Saturated Solution ◽  
Narrow Particle Size Distribution ◽  
Solution Flow Rate ◽  
Process Conditions ◽  
Solution Flow ◽  
Expansion Temperature

Encapsulation of menthol in beeswax was prepared by a modified particles from gas-saturated solutions (PGSS) process with controlling the gas-saturated solution flow rate. Menthol/beeswax particles with size in the range of 2–50 μm were produced. The effects of the process conditions, namely, the pre-expansion pressure, pre-expansion temperature, gas-saturated solution flow rate, and menthol composition, on the particle size, particle size distribution, and menthol encapsulation rate were investigated. Results indicated that in the range of studied conditions, increase of the pressure, decrease of the gas-saturated solution flow rate, and decrease of the menthol mass fraction can decrease the particle size and narrow particle size distribution of the produced menthol/beeswax microparticles. An N2-blowing method was proposed to measure the menthol release from the menthol/beeswax microparticles. Results showed that the microparticles have obvious protection of menthol from its volatilization loss.

Hydrodynamic Properties of Fe 3 O 4 Kerosene-Based Ferrofluids with Narrow Particle Size Distribution

2005 ◽  
Vol 22 (11) ◽  
pp. 2944-2946 ◽  
Author(s):  
Zhang Jian-Hui ◽  
Xu Xue-Fei ◽  
Si Ming-Su ◽  
Zhou You-He ◽  
Xue De-Sheng
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Narrow Particle Size Distribution ◽  
Hydrodynamic Properties

scholarly journals Integrated plug flow synthesis and crystallisation of pyrazinamide

2018 ◽  
Vol 3 (5) ◽  
pp. 631-634 ◽  
Author(s):  
C. Daniel Scott ◽  
Ricardo Labes ◽  
Martin Depardieu ◽  
Claudio Battilocchio ◽  
Matthew G. Davidson ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Plug Flow ◽  
Polymorphic Form ◽  
High Yield ◽  
Narrow Particle Size Distribution ◽  
Coupled Flow ◽  
Flow Synthesis

Pure pyrazinamide has been produced in a coupled flow synthesis and crystallisation in high yield, pure polymorphic form (γ) and narrow particle size distribution.

Scalable Production of Carbon Encapsulated Ni Nanoparticles by Water Arc Discharge: Structural and Magnetic Properties

2005 ◽  
Vol 23 ◽  
pp. 87-90 ◽  
Author(s):  
K.H. Ang ◽  
I. Alexandrou ◽  
N.D. Mathur ◽  
R. Lacerda ◽  
I.Y.Y. Bu ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Arc Discharge ◽  
Narrow Particle Size Distribution ◽  
Ni Nanoparticles ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Water Container

An electric arc discharge in de-ionised water between a solid graphite cathode and an anode made by compressing Ni and C containing powders in a mass ratio of Ni:C = 7:3 was used here to prepare carbon encapsulated Ni nanoparticles in the form of powder suspended in water. The morphology of the produced material was analysed using high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The magnetic properties of the samples were determined using a Princeton vibrating sample magnetometer (VSM). Collection of the powder produced from different depths in the water container has proved to be an effective method for obtaining samples with narrow particle size distribution. Further material purification by dry NH4 plasma etching was used to remove the amorphous carbon content of the samples. XRD and HRTEM analysis showed that the material synthesized is fcc Ni particles with mean particle size ranging from 14 to 30 nm encapsulated in 2 to 5 graphitic cages. The data suggests that the process reported has the ability to mass-produce carbon encapsulated ferromagnetic nanoparticles with desired particle size distribution, and hence with controlled size-dependent magnetic properties.

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