Amphiphilic polystyrene-graft-poly(N,N-dimethylamino-2-ethyl methacrylate) hydrogels synthesized via room temperature ATRP: Studies on swelling behaviour and dye sorption

2008 ◽  
Vol 68 (5) ◽  
pp. 967-973 ◽  
Author(s):  
A.V. Vivek ◽  
R. Dhamodharan
Keyword(s):  
Room Temperature ◽  
Swelling Behaviour ◽  
Ethyl Methacrylate ◽  
Dye Sorption

Swelling pressure and microstructure of an activated swelling clay with temperature

Clay Minerals ◽  
1998 ◽  
Vol 33 (2) ◽  
pp. 255-267 ◽  
Author(s):  
D. Tessier ◽  
M. Dardaine ◽  
A. Beaumont ◽  
A. M. Jaunet
Keyword(s):  
Room Temperature ◽  
Swelling Pressure ◽  
Radioactive Waste Disposal ◽  
Basic Medium ◽  
Hydraulic Pressure ◽  
Swelling Behaviour ◽  
Transmission Electron ◽  
Ca Ions ◽  
Na Ions ◽  
Marked Drop

AbstractClay from Fourges has been selected by the Commissariat à l'Energie Atomique as a support in radioactive waste disposal studies. This material was activated by adding Na2CO3, then compacted at 60 MPa. Subsequently, its swelling behaviour was monitored at 90°C and 145°C for 330 days and at the end of this period the samples were examined by transmission electron microscopy (TEM). For this, they were embedded in a resin then sectioned with an ultramicrotome for mineralogical and chemical analyses. The initial material is essentially composed of kaolinite and smectite. Addition of Na2CO3 at room temperature induces a replacement of Ca ions by Na ions and the precipitation of finely divided carbonates on the surface of the constituents. At the end of 330 days at 90°C under a hydraulic pressure of 1 MPa, the initial particles combine and the material exerts a swelling pressure of 20 MPa. A complete reorganisation of the clay crystallites is observed without significant dissolution of the solid phases. After the same time at 145°C under a hydraulic pressure of 10 MPa, in a basic medium, the combined conditions are such that a high proportion of the clay is dissolved with formation of amorphous aluminosilicates correlated with a marked drop in the swelling pressure to 5 MPa. This work establishes the advantages of following the macroscopic properties in parallel with the microstructure variations for understanding the changes in the properties of clays.

scholarly journals Synthesis and Characterization of Chemically Cross-Linked CMC/Acrylamide Hydrogels

2020 ◽  
Vol 32 (5) ◽  
pp. 1109-1115
Author(s):  
Shivakumara Lachakkal Rudrappa ◽  
Sudhir Ramaswamy Iliger ◽  
Demappa Thippaiah
Keyword(s):  
Room Temperature ◽  
Aluminum Sulfate ◽  
Ammonium Persulfate ◽  
Sem Analysis ◽  
Cross Linking ◽  
Swelling Behaviour ◽  
Buffer Solutions ◽  
Aluminium Sulfate ◽  
Chemical Cross Linking

Carboxymethyl cellulose/poly(acrylamide) (CMC/Amm) hydrogels were synthesized by the chemical cross-linking method. Ammonium persulfate used as an initiator, while aluminium sulfate used as a cross-linking agent. The structure and morphology of the hydrogels were characterized by FTIR and scanning electron microscopy (SEM) analysis. The swelling behaviour of the hydrogels can be studied by using acids (CH3COOH, HCl and HClO4) and also in the pH of the buffer solutions at different temperature (room temperature, 30 and 37 ºC) was studied. Swelling of hydrogels increased with an increase in the concentration of aluminum sulfate up to 20 %, above 20 % it has found to be decreased. The effect of four series of cationic different concentrated salt solutions on the swelling had found to be the following order K+ > Na+ > Ca2+ > Mg2+.

PREPARATION OF SOYPROTEIN BASED NANOPARTICLE

2016 ◽  
Vol 2 (1) ◽  
pp. 45-49
Author(s):  
A Malar Retna ◽  
A Sophia
Keyword(s):  
Graft Copolymer ◽  
Soy Protein ◽  
Room Temperature ◽  
Hydrolytic Stability ◽  
Glass Plate ◽  
Ethyl Methacrylate ◽  
Product Mixture ◽  
Emulsion Polymerisation ◽  
Xrd Studies ◽  
Chemical Resistivity

Soy protein based Nanoparticles were prepared via direct graft copolymerisation of soyprotein isolate (SPI)  with ethyl methacrylate at a temperature of 120◦c using benzoyl peroxide as a catalyst. The technique used here was emulsion polymerisation technique. The products obtained ie., the graft copolymer and the homopolymer Poly(ethyl methacrylate)(PEMA) were separated from the product mixture by dissolving the mixture using  chloroform in a separating funnel.The separated graft copolymer in the emulsion form was then spreaded over a glass plate to make a nano plastic sheet and the sheet was allowed to dry for 24 hrs at room temperature to remove chloroform from it. FTIR study confirmed the grafting of SPI and PEMA. XRD studies confirmed the presence of nanoparticles. TG-DTA, Hydrolytic stability, chemical resistivity and water absorption of the sample were studied. Grafting efficiency and grafting percentage of the sample were calculated.

Template-free and room temperature synthesis of hierarchical porous zeolitic imidazolate framework nanoparticles and their dye and CO2sorption

2018 ◽  
Vol 20 (5) ◽  
pp. 1074-1084 ◽  
Author(s):  
Hani Nasser Abdelhamid ◽  
Xiaodong Zou
Keyword(s):  
Room Temperature ◽  
Sorption Properties ◽  
Temperature Synthesis ◽  
Zeolitic Imidazolate Framework ◽  
Room Temperature Synthesis ◽  
Green Route ◽  
Hierarchical Porous ◽  
Dye Sorption ◽  
Template Free

A green route for synthesis of hierarchical porous zeolitic imidazolate framework nanoparticles has been proposed. The materials exhibit high CO2uptake and selective dye sorption properties.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

Domain Formation in Synthetic Quartz

1971 ◽  
Vol 29 ◽  
pp. 156-157
Author(s):  
Joseph J. Comer
Keyword(s):  
Electron Beam ◽  
Room Temperature ◽  
Domain Formation ◽  
Synthetic Quartz ◽  
Transmission Electron ◽  
Black Spots ◽  
Diffraction Mode ◽  
Domain Boundaries ◽  
Kikuchi Lines ◽  
Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

A Liquid Nitrogen Cooled Stage for STEM

1974 ◽  
Vol 32 ◽  
pp. 444-445
Author(s):  
Louis T. Germinario
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Liquid Nitrogen ◽  
Room Temperature ◽  
Objective Lens ◽  
Thermal Drift ◽  
Specimen Holder ◽  
Resolution Capability ◽  
Focal Position

A liquid nitrogen stage has been developed for the JEOL JEM-100B electron microscope equipped with a scanning attachment. The design is a modification of the standard JEM-100B SEM specimen holder with specimen cooling to any temperatures In the range ~ 55°K to room temperature. Since the specimen plane is maintained at the ‘high resolution’ focal position of the objective lens and ‘bumping’ and thermal drift la minimized by supercooling the liquid nitrogen, the high resolution capability of the microscope is maintained (Fig.4).

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

Benzylamine Tartrate as an Organic Glass Substrate for Carbon Films by Evaporation

1970 ◽  
Vol 28 ◽  
pp. 484-485
Author(s):  
A. C. Faberge
Keyword(s):  
Vapor Pressure ◽  
Viscous Liquid ◽  
Glass Substrate ◽  
Room Temperature ◽  
Carbon Film ◽  
Carbon Films ◽  
Organic Glass ◽  
Spectroscopic Examination ◽  
Polymeric Substrates

Benzylamine tartrate (m.p. 63°C) seems to be a better and more convenient substrate for making carbon films than any of those previously proposed. Using it in the manner described, it is easy consistently to make batches of specimen grids as open as 200 mesh with no broken squares, and without individual handling of the grids. Benzylamine tartrate (hereafter called B.T.) is a viscous liquid when molten, which sets to a glass. Unlike polymeric substrates it does not swell before dissolving; such swelling of the substrate seems to be a principal cause of breakage of carbon film. Mass spectroscopic examination indicates a vapor pressure less than 10−9 Torr at room temperature.

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