The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Yong-hua Zang - One of the best experts on this subject based on the ideXlab platform.
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Effects of Starch on Latex Migration and on Paper Coating Properties
Industrial & Engineering Chemistry Research, 2011Co-Authors: Yong-hua ZangAbstract:With increasing awareness of environmental protection and the surging cost of petroleum chemicals, eco-friendly polymer starches are being increasingly used as cobinders to partly replace synthetic polymer latex in the production of high quality coated papers. In this work, the influences of starch on latex migration and on properties of model clay coatings were investigated, in order to better understand interactions between starch and latex and their effects on coating structure development. The results showed that Surface Carbon Content determined from XPS measurements decreased significantly with increasing starch Content. This unexpected finding of lower Surface Carbon Content for coatings of higher binder Content was explained by assuming that water-soluble starch migrated to the Surface would move back into the coating pores as an integral part of the aqueous phase, as the air–water interfaces recede from the coating Surface into the capillaries during drying. It has also been found that gloss and ...
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The migration of styrene butadiene latex during the drying of coating suspensions: when and how does migration of colloidal particles occur?
Langmuir, 2010Co-Authors: Yong-hua Zang, Juan Du, Yanfen Du, Zhenjuan Wu, Shaoling ChengAbstract:Surface elemental compositions of model latex clay coatings on an impervious substrate consolidated under various conditions were measured using the XPS technique, in order to clarify when and how colloidal latex particles migrate to the Surface during drying. Under similar drying conditions, Surface Carbon Content decreased with the addition of a water-soluble polymer to the coating colors, while remaining virtually unchanged for coatings of different coat weights made with a given color, indicating that Surface Carbon Content variation is mainly caused by migration of latex rather than of water-soluble polymer. The results also showed that for coatings made with a given suspension, Surface Carbon Content decreased with increasing delay time between coating and heating. For coatings frozen during consolidation and dried by sublimation, Surface Carbon Content increased with increasing drying time before freezing. These results suggest that for the model coatings studied, latex migration mainly occurs afte...
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The migration of styrene butadiene latex during the drying of coating suspensions: when and how does migration of colloidal particles occur?
Langmuir : the ACS journal of surfaces and colloids, 2010Co-Authors: Yong-hua Zang, Shaoling Cheng, Yuping LiuAbstract:Surface elemental compositions of model latex clay coatings on an impervious substrate consolidated under various conditions were measured using the XPS technique, in order to clarify when and how colloidal latex particles migrate to the Surface during drying. Under similar drying conditions, Surface Carbon Content decreased with the addition of a water-soluble polymer to the coating colors, while remaining virtually unchanged for coatings of different coat weights made with a given color, indicating that Surface Carbon Content variation is mainly caused by migration of latex rather than of water-soluble polymer. The results also showed that for coatings made with a given suspension, Surface Carbon Content decreased with increasing delay time between coating and heating. For coatings frozen during consolidation and dried by sublimation, Surface Carbon Content increased with increasing drying time before freezing. These results suggest that for the model coatings studied, latex migration mainly occurs after coating application before capillary formation during the initial drying stage when coatings are in the liquid phase, contradicting both the conventional capillary transport and boundary wall migration mechanisms. An alternative mechanism which attributes latex migration to Surface trapping effect and to higher Brownian mobility of the smaller latex particles compared with pigment appears to provide a systematically consistent explanation to those phenomena. The new particle migration mechanism implies that segregation of colloidal particles is a ubiquitous phenomenon that would occur not only during the drying of paper coatings but also during consolidation of colloidal films containing particles of different sizes. This is of great importance in the control of Surface compositions of nanocomposite coatings.
Shaoling Cheng - One of the best experts on this subject based on the ideXlab platform.
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The migration of styrene butadiene latex during the drying of coating suspensions: when and how does migration of colloidal particles occur?
Langmuir, 2010Co-Authors: Yong-hua Zang, Juan Du, Yanfen Du, Zhenjuan Wu, Shaoling ChengAbstract:Surface elemental compositions of model latex clay coatings on an impervious substrate consolidated under various conditions were measured using the XPS technique, in order to clarify when and how colloidal latex particles migrate to the Surface during drying. Under similar drying conditions, Surface Carbon Content decreased with the addition of a water-soluble polymer to the coating colors, while remaining virtually unchanged for coatings of different coat weights made with a given color, indicating that Surface Carbon Content variation is mainly caused by migration of latex rather than of water-soluble polymer. The results also showed that for coatings made with a given suspension, Surface Carbon Content decreased with increasing delay time between coating and heating. For coatings frozen during consolidation and dried by sublimation, Surface Carbon Content increased with increasing drying time before freezing. These results suggest that for the model coatings studied, latex migration mainly occurs afte...
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The migration of styrene butadiene latex during the drying of coating suspensions: when and how does migration of colloidal particles occur?
Langmuir : the ACS journal of surfaces and colloids, 2010Co-Authors: Yong-hua Zang, Shaoling Cheng, Yuping LiuAbstract:Surface elemental compositions of model latex clay coatings on an impervious substrate consolidated under various conditions were measured using the XPS technique, in order to clarify when and how colloidal latex particles migrate to the Surface during drying. Under similar drying conditions, Surface Carbon Content decreased with the addition of a water-soluble polymer to the coating colors, while remaining virtually unchanged for coatings of different coat weights made with a given color, indicating that Surface Carbon Content variation is mainly caused by migration of latex rather than of water-soluble polymer. The results also showed that for coatings made with a given suspension, Surface Carbon Content decreased with increasing delay time between coating and heating. For coatings frozen during consolidation and dried by sublimation, Surface Carbon Content increased with increasing drying time before freezing. These results suggest that for the model coatings studied, latex migration mainly occurs after coating application before capillary formation during the initial drying stage when coatings are in the liquid phase, contradicting both the conventional capillary transport and boundary wall migration mechanisms. An alternative mechanism which attributes latex migration to Surface trapping effect and to higher Brownian mobility of the smaller latex particles compared with pigment appears to provide a systematically consistent explanation to those phenomena. The new particle migration mechanism implies that segregation of colloidal particles is a ubiquitous phenomenon that would occur not only during the drying of paper coatings but also during consolidation of colloidal films containing particles of different sizes. This is of great importance in the control of Surface compositions of nanocomposite coatings.
Mehrdad Kashefi - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Variables Affecting Impedance Plane in Eddy Current Testing of Carburized Steels
Journal of Materials Engineering and Performance, 2010Co-Authors: Meisam Sheikh Amiri, Mehrdad KashefiAbstract:Impedance plane is one of the most important ways for presenting results in Eddy current testing, which includes major data for evaluation of results. In this study, the impedance plane was drawn for carburized steel with different Surface Carbon Content. The influences of temperature, fill factor, and edge effect on impedance plane were investigated. The ability of Eddy current testing for determination of Surface Carbon Content using normalized impedance was also shown. Results demonstrate a strong relationship between normalized impedance and Surface Carbon Content (R 2 = 0.82). Besides the effects of temperature, fill factor, and edge effect on determination of Surface Carbon Content were investigated. The fill factor and temperature have the largest and the least effect on correlation coefficient between Surface Carbon Content and impedance plane, respectively.
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Application of eddy current nondestructive method for determination of Surface Carbon Content in carburized steels
NDT & E International, 2009Co-Authors: Meisam Sheikh Amiri, Mehrdad KashefiAbstract:Abstract Apart from traditional application of nondestructive eddy current technique for detection of discontinuities, the method has been recently used to determine physical and metallurgical properties of steel parts. In the present research the application of eddy current method for determination of Surface Carbon of steel parts in gas carburizing process has been studied. The relation between the Surface Carbon Content and various parameters such as impedance, phase angle and voltage has been established. Besides the effect of Carbon Content of the impedance plain has been investigated. The study shows that the best relation (R2=0.91) can be achieved using phase angle.
Kuniaki Tatsumi - One of the best experts on this subject based on the ideXlab platform.
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Effect of Surface Carbon Content in LiFePO4/C Composite Electrodes Prepared by Spark-Plasma-Sintering Process
2006Co-Authors: Tomonari Takeuchi, Mitsuharu Tabuchi, Kazuaki Ado, Kuniaki TatsumiAbstract:INTRODUCTION For the electrode materials in practical lithium-ion batteries, a high rate capability, in addition to a high energy density, is one of the most important characteristics (1). However, lithium-ion cells cycled at a relatively high current density exhibit a significant power loss associated with a rise in the positive electrode impedance; some active particles become electrically disconnected with the remaining part of the positive electrode (1). For improving the connection, the introduction of conductive additives, such as Carbon coating on the Surface of LiFePO4, has been attempted, and it was effective for successfully improving the cell specific capacity (2). However, Carbon coating usually decreased the cathode density due to their bulky volume, which could lower volumetric energy of the cell. Spark-plasma-sintering (SPS) is a process that makes use of electrical discharge between particles, and it generates strong binding between particles to form dense solids. Recently, we applied this technique to the mixture of LiFePO4 and acetylene black powders and obtained dense LiFePO4/C composite electrodes (3). In the present work, for further improving the homogeneity of Carbon distribution and their binding, we added the liquid-state organic materials on the Surface of LiFePO4 particles. The Surface Carbon Content was examined to optimize the preparation route for dense composite electrodes.
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effect of Surface Carbon Content in lifepo4 c composite electrodes prepared by spark plasma sintering process
Meeting Abstracts, 2006Co-Authors: Tomonari Takeuchi, Mitsuharu Tabuchi, Kazuaki Ado, Kuniaki TatsumiAbstract:INTRODUCTION For the electrode materials in practical lithium-ion batteries, a high rate capability, in addition to a high energy density, is one of the most important characteristics (1). However, lithium-ion cells cycled at a relatively high current density exhibit a significant power loss associated with a rise in the positive electrode impedance; some active particles become electrically disconnected with the remaining part of the positive electrode (1). For improving the connection, the introduction of conductive additives, such as Carbon coating on the Surface of LiFePO4, has been attempted, and it was effective for successfully improving the cell specific capacity (2). However, Carbon coating usually decreased the cathode density due to their bulky volume, which could lower volumetric energy of the cell. Spark-plasma-sintering (SPS) is a process that makes use of electrical discharge between particles, and it generates strong binding between particles to form dense solids. Recently, we applied this technique to the mixture of LiFePO4 and acetylene black powders and obtained dense LiFePO4/C composite electrodes (3). In the present work, for further improving the homogeneity of Carbon distribution and their binding, we added the liquid-state organic materials on the Surface of LiFePO4 particles. The Surface Carbon Content was examined to optimize the preparation route for dense composite electrodes.
Hada Y. Gonzalez - One of the best experts on this subject based on the ideXlab platform.
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Wettability of silane-treated glass slides as determined from X-ray photoelectron spectroscopy
Journal of Colloid and Interface Science, 1995Co-Authors: Y.carolina Araujo, Pedro G. Toledo, Vladimir Leon, Hada Y. GonzalezAbstract:Abstract The wettability and stability of silane-treated substrates are central in many processes of industrial and environmental interest. Here, we bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of treated glass. For a suite of silane-treated slides we investigate the relationship between wettability and Surface composition as determined from XPS. The adhesion behavior and contact angle of mineral oil on brine-covered Surfaces are used here as Surface wettability indicators. The XPS spectra of silanes and silane-treated glass slides indicate that silicon species of the kind Si–CH exhibit a well-defined binding energy which differs from that of the Si–O species of the glass. The presence of the Si–CH species reveals glass Surfaces that have been rendered hydrophobic by chemisorption of organic matter. The Surface Carbon Content as determined from XPS correlates strongly with the equilibrium contact angle, contact angle hysteresis, adhesion behavior, and wettability state. This correlation can be used to rapidly determine the wettability of treated glass.
