A Dramatic Change in Rheological Behavior of a Clay Material Caused by a Minor Addition of Hydrophilic and Amphiphilic Polyelectrolytes

Wide usage of clay-based materials in industry requires investigations concerning efficient modification techniques to control their mechanical behavior in aqueous media. The challenging problem in this field involves minimization of the modifying agent content to provide marked changes in the operating characteristics of the material. In this work, the physicochemical, mechanical and structural aspects of the interaction of capillary water-saturated kaolinite with polyelectrolytes were studied. Modification of kaolinite with a negligible amount (0.1 wt.%) of hydrophilic and amphiphilic polyelectrolytes provides the control for rheological parameters of kaolinite suspensions such as storage and loss modulus in the range of three orders of magnitude. The results obtained reveal the wide possibilities for the production of a spectrum of clay materials using minor amounts of polymer modifying agents.

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SYNTHESIS AND VISCOELASTIC BEHAVIORS OF POLY(ANILINE-CO-O-ETHOXYANILINE) PARTICLES SUSPENDED ELECTRORHEOLOGICAL FLUID

International Journal of Modern Physics B ◽

10.1142/s0217979201005118 ◽

2001 ◽

Vol 15 (06n07) ◽

pp. 649-656 ◽

Cited By ~ 10

Author(s):

H. J. CHOI ◽

J. W. KIM ◽

M. S. SUH ◽

M. J. SHIN ◽

K. TO

Keyword(s):

Particle Size ◽

Silicone Oil ◽

Loss Modulus ◽

Chemical Oxidation ◽

Steady Shear ◽

Rheological Parameters ◽

Linear Viscoelastic Region ◽

Linear Viscoelastic ◽

Er Fluids ◽

Poly Aniline

Copolyanilines are synthesized by a chemical oxidation of aniline and o-ethoxyaniline with various molar ratios in an acidic media, and then characteristics of these polymers such as chemical structure, particle size and the particle size distribution were examined by using FT-IR, SEM and particle size analyzer, respectively. Suspensions of copolyaniline containing ethoxy group, namely poly(aniline-co-o-ethoxyaniline), in silicone oil have been investigated as one of many potential candidates for dry-base electrorheological (ER) fluid systems. Rotational rheometer (Physica) equipped with a high voltage generator was used to characterize the rheological properties of ER fluids from both steady shear and dynamic tests. From the steady shear experiment, we obtained flow properties and found that ER fluids exhibited the yield phenomenon. On the other hand, viscoelastic property was also obtained from the dynamic experiment. Since viscoelastic properties for ER fluids are mainly dominated by the particle chain structure, the state at different time scale was analyzed from the rheological parameters such as storage modulus (G'), loss modulus (G'') and tan δ. We conducted a strain amplitude sweep at 1 Hz under an applied electric field to determine a linear viscoelastic region first. The G' and G'' were then measured by a frequency sweep from 0.1 to 100 Hz in the linear viscoelastic region.

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Investigation into the hygrothermal behavior of fired clay materials during the freezing of supercooled water using experiments and numerical simulations

Journal of Building Physics ◽

10.1177/17442591211041144 ◽

2021 ◽

pp. 174425912110411

Author(s):

Kazuma Fukui ◽

Chiemi Iba ◽

Madoka Taniguchi ◽

Kouichi Takahashi ◽

Daisuke Ogura

Keyword(s):

Surface Area ◽

Water Saturation ◽

Supercooled Water ◽

Clay Material ◽

Experimental Conditions ◽

Cooling Rates ◽

Freezing Points ◽

Hygrothermal Behavior ◽

Short Period ◽

Clay Materials

In this study, supercooling effects on the hygrothermal behavior of fired clay materials under various experimental conditions, such as water content, cooling rates, and size of specimens were investigated using experimental methods and hygrothermal simulations. We report results of the differential scanning calorimetry (DSC) and temperature distribution changes during a freeze–thaw (FT) experiment using unsaturated specimens. Also, we developed a numerical model of the freezing and thawing processes including the supercooling processes. The DSC results show the freezing of the supercooled water in a fired clay material is considerably faster than that in cement-based materials. It was also found that the dependency of the supercooling effects on the cooling rates seemed to be small. When the water saturation of a material decreases, the rate of the ice saturation increase during the freezing of the supercooled water is decreased while the freezing points of the supercooled water was not changed considerably. The comparison of the results of the FT experiment and hygrothermal simulations show that the combination of the existed hygrothermal model and a modified kinetic equation can reproduce the rapid temperature rise during the freezing of the supercooling water in the FT experiment. Finally, the size effects of specimens on the supercooling phenomenon was discussed based on the experimental and calculation results. The freezing points got higher when a specimen was larger. Due to differences in the ratio of the surface area to the volume, hygrothermal behavior in small specimens and relatively large specimens like that of the DSC and the FT experiment, respectively were markedly different. Water in a relatively large specimen with a small ratio of surface area to volume can achieve the thermodynamic equilibrium in a short period after the freezing starts.

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Rheological properties of cholesteric liquid crystals as lubricant additives

International Journal of Modern Physics B ◽

10.1142/s0217979219500140 ◽

2019 ◽

Vol 33 (05) ◽

pp. 1950014 ◽

Cited By ~ 1

Author(s):

A. Bindu Madhavi ◽

S. Sreehari Sastry

Keyword(s):

Shear Rate ◽

Rheological Properties ◽

Loss Modulus ◽

Flow Behavior ◽

Lubricant Additives ◽

Rheological Parameters ◽

Practical Applications ◽

Phase Transition Temperatures ◽

Frequency Independent ◽

Temperature Shear

Rheological properties of Cholesteryl n-valerate, Cholesteryl decanoate and Cholesteryl myristate which are esters of cholesterol have been studied. Phase transition temperatures and rheological parameters such as viscosity, elastic modulus G[Formula: see text], loss modulus G[Formula: see text] as functions of temperature, shear rate and time are investigated. In frequency sweep test, a higher transition crossover region has occurred for Cholesteryl myristate, whereas for Cholesteryl n-valerate a frequency-independent plateau prevailed for both the moduli. The occurrence of blue phase in Cholesteryl decanoate during temperature sweep measurements is an indication for the rheological support. The results for steady state have informed that cholesteric esters are having non-Newtonian flow behavior in their respective cholesteric phases. The power-law model has explained well the shear rate dependence of shear stress. A few practical applications of these esters as lubricant additives are discussed, too.

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Processing properties of polypropylene with a minor addition of silicone oil

Polymer Engineering & Science ◽

10.1002/pen.21665 ◽

2010 ◽

Vol 50 (7) ◽

pp. 1340-1349 ◽

Cited By ~ 7

Author(s):

Wei Zhang ◽

Sarang Deodhar ◽

Donggang Yao

Keyword(s):

Silicone Oil ◽

Minor Addition ◽

A Minor ◽

Processing Properties

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The Refinement of the Nanoporous Copper by Adding Third Elements

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.1986 ◽

2014 ◽

Vol 783-786 ◽

pp. 1986-1989

Author(s):

Zhen Hua Dan ◽

Feng Xiang Qin ◽

Nobuyoshi Hara

Keyword(s):

Lower Surface ◽

Pore Sizes ◽

Surface Diffusivity ◽

Minor Addition ◽

Cu Alloys ◽

Nanoporous Copper ◽

Order Of Magnitude ◽

A Minor ◽

Trace Formation ◽

Nanoporous Structures

Fine nanoporous copper was fabricated from the amorphous Ti-Cu alloys with a minor addition of silver in 10 mM HF solutions. The pore sizes decreased from 100 nm to 12 nm with the increase of the Ag contents in comparison of Ti60Cu40 ribbons free of Ag. With increasing of the dealloying time, the sizes of the nanopores and ligaments increased for the nanostrucutres on Ti60Cu38Ag2 ribbons since the segregation of the Ag phase which triggered the galvanic dissolution of the adjacent Cu matrix in form of micro-couplings to further coarsen the nanoporous Cu. On the contrary, the trace formation of the Ag phase on the Ti60Cu39Ag1 ribbons had a weak ability to motivate the galvanic dissolution, indicating by the constant pore sizes and slight decrease in the ligament sizes with the increase in the dealloying time. The refinement of the nanoporous structures was ascribed to the drastic decrease in the surface diffusivity. The decrease in the surface diffusivity due to the involvement of Ag with a lower surface diffusivity in comparison of Cu was more than one order of magnitude. The involvement of Ag adatoms restricted the diffusion of Cu adatoms in the interface regions in the inward and outward directions.

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Cobalt(II) phosphonate coordination polymers: Synthesis, characterization and application as oxygen evolution electrocatalysts in aqueous media and water-saturated hydrophobic 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid

Electrochimica Acta ◽

10.1016/j.electacta.2012.09.093 ◽

2013 ◽

Vol 101 ◽

pp. 201-208 ◽

Cited By ~ 17

Author(s):

Yuping Liu ◽

Si-Xuan Guo ◽

Alan M. Bond ◽

Jie Zhang ◽

Shaowu Du

Keyword(s):

Ionic Liquid ◽

Oxygen Evolution ◽

Coordination Polymers ◽

Aqueous Media ◽

Water Saturated

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Pleistocene soils of the Azov Lowland, Ukraine

Journal of Geology Geography and Geoecology ◽

10.15421/111931 ◽

2019 ◽

Vol 28 (2) ◽

pp. 313-326

Author(s):

S. P. Karmazinenko

Keyword(s):

Soil Formation ◽

Soil Conditions ◽

Clay Material ◽

Color Structure ◽

Low Profile ◽

Modern Soil ◽

Heavy Loam ◽

Dark Colour ◽

Warm Temperate ◽

Clay Materials

With the aim to reconstruct the Pleistocene soils in Azov Lowland (geological sections near the villages of Bezimenne and Melekinе Donetsk region), we carried out palaeopedological research. The Paleopedological method was used, which consisted with a detailed analysis of the morphological (color, structure, granulometric composition, humidity, composition, neoplasms, inclusion, transition between horizons, border) and micromorphological (skeleton, plasma, color, aggregation, porosity, organic and clay parts, mineral skeleton, tumors, microstructure) features. Paleopedological studies of Pleistocene soils have allowed to determine the types of these deposits and to follow the dynamics of changes in soil conditions: - warm-temperate with signs and close to subtropical, when formed reddish cinnamon (krb1), reddish brown (krb2), cinnamonish-brown (shb1), reddish cinnamon (shb2), dark-colour (meadow reddish cinnamon) merged (mrb2 + mrb1), reddish cinnamon, brownish, fused saline soils (mr3) Kryzhanivka, Shyrokyno and Martonosha soils, which are distinguished by reddish shades of coloring of the profiles, are the most ferruginous, clay, with a large number of nodules witch concentration of organo-iron-clay material; - moderately-warm transition to subtropical – red-brown saline (lbb2), dark-colour (brownish-cinnamonic) fused (lbb2 + lbb1) heavy loam Lubny soils, with are less clayed, ferruginous and formed in meadow-steppe and steppe conditions (brownish-gray with cinnamonish shades of coloring profiles,the presence of moleholes, complex microaggregation); - moderately variable – humid close to subtropical – cinnamon and cinnamonsaline (zvb1), reddish-cinnamon saline (zvb2), heavy loam Zavadivka soils, which are a transitional variant to temperate climates, although some of the features of the lower Pleistocene soil formation are retained (ferrugination, presence of segregated clusters organo-clay and clay materials, microortshteins); - moderately-warm equally humid – cinnamon-brown (kdb1), ordinary chernozems (kdb2), cinnamonish-gray saline (plb1), chernozem saline (plb2), brown steppe (plc), heavy and medium loam Kaydaky and Pryluky soils, characterized by the grayish shades of coloring of profiles, the presence of moleholes, carbonates, complex microaggregates, pores and are closest to modern soils; - moderately-warm subarid – cinnamonish-brown (vtb2) heavy loam Vytachiv soils formed under the influence of turf (the presence of crust, carbonate, complex microaggregates) and brown-liked (cinnamonish-brown color of the profile,spatial structure of clays) of soil formation processes and have no analogues in modern soil cover; - moderately-continental and more arid (dry) – chernozems saline (dfb2), brown saline (dfc), desert-steppe fulvous (dfc), medium loam Dofinivka soils, with clear features of xeromorphism (low profile power, its carbonate, lack of signs of organo-mineral materials) replacing.

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Self-cured polymers from non-drying oil

Chemistry & Chemical Technology ◽

10.23939/chcht02.04.285 ◽

2008 ◽

Vol 2 (4) ◽

pp. 285-293

Author(s):

Fahmina Zafar ◽

◽

Syed Marghoob Ashraf ◽

Sharif Ahmad ◽

◽

...

Keyword(s):

Corrosion Resistance ◽

Phthalic Anhydride ◽

Chemical Corrosion ◽

Spectral Techniques ◽

Drying Oil ◽

Minor Addition ◽

Pongamia Glabra ◽

Physico Chemical ◽

Ft Ir ◽

A Minor

Pongamia glabra seed oil (PGSO) – a non-edible, non-drying oil; a sustainable resource has found application as alkyds, epoxies and polyesteramides in paints and coatings. Generally, PGSO based polymeric coatings are obtained by curing at elevated temperature. Efforts have been made to cure PGSO at room temperature by simple route modification. Self-cured Pongamia glabra oil based on polyesteramide (APGPEA) resin was synthesized by the reaction between Pongamia glabra oil modified fatty amide diol (HEPGA) with polystyrene co-maleic anhydride (SMA). After complete synthesis of APGPEA, phthalic anhydride modified polyesteramide (APGPEAPh) was synthesized in situ by a minor addition of phthalic anhydride (PA) to APGPEA in order to improve the performance of the latter. The effect of the SMA and PA introduction on properties of PGPEAPh film was also investigated. The physico-chemical characteristics of both resins were obtained by standard laboratory methods. The structural elucidation of these resins was carried out by FT-IR, 1H-NMR and 13C-NMR spectral techniques. The thermal behavior was studied by TGA. Curing was studied by DSC and FT-IR techniques. It was observed that APGPEA and APGPEAPh resins significantly improve the drying property in contrast to the previously reported polyesteramides cured at high temperature. Physico-mechanical and chemical/corrosion resistance tests of APGPEAPh coatings showed that the presence of phthalic anhydride in APGPEA enhanced the physico-mechanical and corrosion resistance considerably. The APGPEAPh resin appears to be sustainable aspirant biomaterials for anticorrosive surface coatings which may substitute polymers obtained from petroleum, potentially scarce resource.

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α-Fe2O3 Nanoparticles/Vermiculite Clay Material: Structural, Optical and Photocatalytic Properties

Materials ◽

10.3390/ma12111880 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1880 ◽

Cited By ~ 10

Author(s):

Marta Valášková ◽

Jonáš Tokarský ◽

Jiří Pavlovský ◽

Tomáš Prostějovský ◽

Kamila Kočí

Keyword(s):

Photocatalytic Activity ◽

Environmental Remediation ◽

Photocatalytic Properties ◽

Structural Defects ◽

Clay Material ◽

Fe2o3 Nanoparticles ◽

X Ray ◽

Vis Spectroscopy ◽

Clay Materials ◽

Vermiculite Clay

Photocatalysis is increasingly becoming a center of interest due to its wide use in environmental remediation. Hematite (α-Fe2O3) is one promising candidate for photocatalytic applications. Clay materials as vermiculite (Ver) can be used as a carrier to accommodate and stabilize photocatalysts. Two different temperatures (500 °C and 700 °C) were used for preparation of α-Fe2O3 nanoparticles/vermiculite clay materials. The experimental methods used for determination of structural, optical and photocatalytic properties were X-ray fluorescence (ED-XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray spectrometry (EDS), N2 adsorption method (BET), diffuse reflectance UV-Vis spectroscopy (DRS), photoluminescence spectroscopy (PL) and photocatalytic reduction of CO2, respectively. The data from XRD were confronted with molecular modeling of the material arrangement in the interlayer space of vermiculite structure and the possibility of anchoring the α-Fe2O3 nanoparticles to the surface and edge of vermiculite. Correlations between structural, textural, optical and electrical properties and photocatalytic activity have been studied in detail. The α-Fe2O3 and α-Fe2O3/Ver materials with higher specific surface areas, a smaller crystallite size and structural defects (oxygen vacancies) that a play crucial role in photocatalytic activity, were prepared at a lower calcination temperature of 500 °C.

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