scholarly journals Using scanning electron microscopy, x-ray diffraction and IR spectroscopy to study the ageing of intumescent fire-proof coatings

2020 ◽  
Vol 29 (5) ◽  
pp. 60-70
Author(s):  
M. Yu. Umrikhina ◽  
T. O. Shorokhova ◽  
L. A. Pyankova ◽  
A. A. Kudryavtsev ◽  
S. V. Utkin
Keyword(s):  
Ir Spectroscopy ◽  
Service Life ◽  
Fire Resistance ◽  
Residual Life ◽  
Ammonium Polyphosphate ◽  
Swelling Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Microscopies ◽  
Scanning Electron

Introduction. The fire protection of metal structures is a relevant present-day problem; its solution implies better fire resistance performance of structures attainable through the application of intumescent fire-proof coatings whose service life expectancy is limited.Goals and objectives. Comprehensive studies of domestically made coating samples were performed to analyze the changes in the chemical composition of intumescent coatings containing ammonium polyphosphate, melamine, and pentaerythritol. The samples were exposed to artificial climatic ageing (3, 6, and 9 years). Methods. Optical and scanning electron microscopies were used to study the appearance of samples, the morphology of inclusions and the surface microstructure. X-ray diffraction and IR spectroscopy were employed to study the phase and structural states of samples, and the swelling ratio of fire-proof coatings was also examined.Results and discussion. It’s been found out that the swelling ratio of samples goes down to a significant extent as the time progresses, and when the residual life of a coating reaches 30 %, the fire resistance limit of the structure goes down. Sample ageing is the reason for gradual phase composition changes due to the melamine content reduction by 40 %, ammonium polyphosphate content reduction by 15 % and redistribution of other components that change the microstructure of coatings, as well as their fire retarding properties.Conclusions. The changes, influencing the ability of a coating to maintain its fire retarding efficiency as declared by the manufacturer, take place in the course of operation of a coating exposed to external factors. The regularities, identified by virtue of this research, can be used to study the samples taken at fire-proofed facilities to identify deviations from the initial condition of a coating and to forecast its actual service life.

Preparation and Characterization of A Composite Obtained through Ti (IV) and Phosphoric Acid

2014 ◽  
Vol 775-776 ◽  
pp. 97-101
Author(s):  
Loanda Raquel Cumba ◽  
U.O. Bicalho ◽  
D.R. Carmo
Keyword(s):  
Phosphoric Acid ◽  
Titanium Isopropoxide ◽  
Deionized Water ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Microscopies ◽  
Prepared Material ◽  
Scanning Electron

This paper describes the preparation and complementary characterization of a composite formed from the activation of titanium isopropoxide by phosphoric acid and deionized water (TiP).Techniques such as, X-ray diffraction (XRD), Raman , electronic (UV-vis) and Scanning electron microscopies (SEM) were used for characterization of this new composite formed. In the X-ray diffractogram of TIP was observed four intense peaks. A strong absorption was observed in the region 362-445 nm. The scanning electron microscopy of TiP, shows that the prepared material consists mostly of a cluster of spherical particles with diameters ranging from 2.35 to 2.60 μm.

scholarly journals STUDY ON CATALYTIC ACTIVITY OF TIO2/SIO2, IN THE OXIDATION OF STYRENE

2009 ◽  
Vol 12 (3) ◽  
pp. 77-84
Author(s):  
Thao Tien Nguyen ◽  
Ngoan Thi Nguyen ◽  
Long Van Dang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Catalytic Activity ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Scanning Electron

All TiO2/SiO2 samples were prepared by the impregnation of Ti(i-PrO)4 in isopropanol at room temperature followed drying and calcination. The solids were characterized by several techniques including X- ray diffraction (XRD), IR spectroscopy, Scanning Electron Microscopy (SEM). No reflection lines of TiO2 are detected at a low content of TiO2 (< 7%), but are more visible at a higher concentration. The catalysts are tested in the liquid oxidation of styrene under mild conditions, producing mainly benzaldehyde. The effects of variables on the catalytic activity are also investigated.

scholarly journals Fabrication, Structure and Functional Characterizations of pH-Responsive Hydrogels Derived from Phytoglycogen

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2653
Author(s):  
Xiuting Hu ◽  
Yao Liu ◽  
Yimei Chen ◽  
Tao Zhang ◽  
Ming Miao
Keyword(s):  
Electrostatic Repulsion ◽  
Swelling Ratio ◽  
Ph Responsive ◽  
X Ray Diffraction ◽  
Carrier System ◽  
Bioactive Substances ◽  
X Ray ◽  
Gelation Rate ◽  
Responsive Hydrogels ◽  
Scanning Electron

The pH-responsive hydrogels were obtained through successive carboxymethylation and phosphorylase elongatation of phytoglycogen and their structure and functional characterizations were investigated. Phytoglycogen (PG) was first carboxymethylated to obtain carboxymethyl phytoglycogen (CM-PG) with degree of substitution (DS) at 0.15, 0.25, 0.30, and 0.40, respectively. Iodine staining and X-ray diffraction analysis suggested that the linear glucan chains were successfully phosphorylase-elongated from the non-reducing ends at the CM-PG surface and assembled into the double helical segments, leading to formation of the hydrogel. The DS of CM-PG significantly influenced elongation of glucan chains. Specifically, fewer glucan chains were elongated for CM-PG with higher DS and the final glucan chains were shorter, resulting in lower gelation rate of chain-elongated CM-PG and lower firmness of the corresponding hydrogels. Scanning electron microscope observed that the hydrogels exhibited a porous and interconnected morphology. The swelling ratio and volume of hydrogels was low at pH 3–5 and then became larger at pH 6–8 due to electrostatic repulsion resulting from deprotonated carboxymethyl groups. Particularly, the hydrogel prepared from chain-elongated CM-PG (DS = 0.25) showed the highest sensitivity to pH. These results suggested that phosphorylase-treated CM-PG formed the pH-responsive hydrogel and that the elongation degree and the properties of hydrogels depended on the carboxymethylation degree. Thus, it was inferred that these hydrogels was a potential carrier system of bioactive substances for their targeted releasing in small intestine.

scholarly journals BIORREMEDIATION OF EMERGING POLLUTANTS WITH THE USE OF STRUCTURED MATERIALS

2017 ◽  
Vol 14 (28) ◽  
pp. 87-104
Author(s):  
Mima Sales Loiola ROSA ◽  
Luís Antônio Oliveira NUNES ◽  
Ives Brian Campelo Leite SILVA ◽  
Francisco Cardaso FIGUEIREDO ◽  
José Ribeiro dos SANTOS JUNIOR
Keyword(s):  
Emerging Pollutants ◽  
Energy Dispersive ◽  
Chemical Adsorption ◽  
X Ray Diffraction ◽  
Structured Materials ◽  
X Ray ◽  
Electron Microscopies ◽  
Bioremediation Processes ◽  
Scanning Electron

Human activities in industry, transportation, agriculture and urbanization have been generating the release of emerging pollutants, in other words substances resistant especially in water bodies such as drugs, endocrine disruptors, heavy metals, textile dyes, chloride compounds, nitro phenols and pesticides. For the treatment of systems reached by these emerging pollutants, the bioremediation process has been used worldwide, and consists in using microorganisms that degrade pollutants. This process can be potentiated using structured materials that immobilize the microorganisms by physical or chemical adsorption and transports them to the pollutant. This review highlights the characterization of the structured immobilized or free materials by Scanning Electron Microscopies (SEM) and Transmission (TEM), Energy Dispersive Spectroscopy (EDS), Energy Dispersive X-ray Analysis (EDAX), Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD) and the influence of the pH on immobilization and bioremediation processes.

Extractive-Pyrolytic Method for Au/MeOx Nanocomposites Production

2014 ◽  
Vol 604 ◽  
pp. 118-121 ◽  
Author(s):  
Vera Serga ◽  
Lidiya Kulikova ◽  
Anton Cvetkov ◽  
George Chikvaidze ◽  
Maris Kodols
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ir Spectroscopy ◽  
X Ray Diffraction ◽  
Organic Extract ◽  
X Ray ◽  
Mean Size ◽  
The Mean ◽  
Scanning Electron

Au/MeOx(MeOx- SiO2, Al2O3and TiO2) nanocomposites have been produced by the extractive-pyrolytic method. An organic extract – a solution of n-trioctylammonium tetrachlorolaurate ([Oct3NH]AuCl4) in toluene – was used as a gold-containing precursor. The produced samples were analyzed by IR spectroscopy, X-ray diffraction and scanning electron microscopy. The performed studies have shown that the mean size of the metal crystallites vary within wide limits: on Al2O3from 60 nm to 35 nm; on SiO2from 33 nm to 23 nm; on TiO2from 50 nm to 13 nm.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Sem and X-Ray Analysis of Renal and Biliary Calculi

1976 ◽  
Vol 34 ◽  
pp. 306-307
Author(s):  
R. J. Narconis ◽  
G. L. Johnson
Keyword(s):  
Chemical Constituents ◽  
Natural State ◽  
X Ray Diffraction ◽  
Chemical Methods ◽  
X Ray ◽  
Additional Dimension ◽  
Biliary Calculi ◽  
Calculus Formation ◽  
Scanning Electron

Analysis of the constituents of renal and biliary calculi may be of help in the management of patients with calculous disease. Several methods of analysis are available for identifying these constituents. Most common are chemical methods, optical crystallography, x-ray diffraction, and infrared spectroscopy. The application of a SEM with x-ray analysis capabilities should be considered as an additional alternative.A scanning electron microscope equipped with an x-ray “mapping” attachment offers an additional dimension in its ability to locate elemental constituents geographically, and thus, provide a clue in determination of possible metabolic etiology in calculus formation. The ability of this method to give an undisturbed view of adjacent layers of elements in their natural state is of advantage in determining the sequence of formation of subsequent layers of chemical constituents.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Sign in / Sign up

Export Citation Format

Share Document