Effect of Sodium Periodate Selective Oxidation on Crystallinity of Cotton Cellulose

2011 ◽  
Vol 197-198 ◽  
pp. 1201-1204 ◽  
Author(s):  
Yun Hui Xu ◽  
Chen Huang
Keyword(s):  
Sodium Periodate ◽  
Periodate Oxidation ◽  
Oxidation Time ◽  
Cotton Cellulose ◽  
Differential Scanning Calorimetric ◽  
Oxidized Cellulose ◽  
Cotton Thread ◽  
Structure Changes ◽  
Higher Temperature ◽  
Lower Temperature

The cotton fiber was oxidized to dialdehyde cellulose by sodium periodate oxidation reaction. The oxidized cotton samples having different oxidation level were obtained with adjusting the periodate concentration and oxidation time. The wide angle X-ray diffraction analysis indicated the crystallinity of the cotton cellulose by the slight oxidation increased, whereas the crystallinity decreased significantly with increase in the degree of oxidation of the cotton cellulose. Differential scanning calorimetric curves of the oxidized samples showed that the slightly oxidized cotton cellulose decomposed at a somewhat higher temperature than the original cotton cellulose in the endothermic decomposition stages up to 350 . However, as the periodate concentration and oxidation time were enhanced further, the endothermic decomposition peak of the oxidized cotton cellulose shifted fast to lower temperature. Furthermore, the changes in the structure and crystallinity were also reflected in the mechanical property studies of these oxidized cellulose samples. The mechanical strength of the cotton thread, which was oxidized by periodate at the concentration of 0.0–1.0 mg/ml and oxidation time for 0–3 h, was found to be almost the same as the original cotton thread, but it decreased remarkably when the oxidation conditions became stronger. These results obtained suggest information in understanding the crystalline structure changes of cellulose in periodate oxidation and planning applications of the oxidized cellulose products.

Crosslinking Properties on Oxidized Cotton Cellulose and Chitosan with Low Molecular Weight

2011 ◽  
Vol 332-334 ◽  
pp. 100-103
Author(s):  
Yun Hui Xu ◽  
Yong Jin Deng
Keyword(s):  
Molecular Weight ◽  
Cotton Fiber ◽  
Sodium Periodate ◽  
Periodate Oxidation ◽  
Covalent Bond ◽  
Cotton Cellulose ◽  
Cotton Fibers ◽  
Low Molecular Weight ◽  
Aqueous Acetic Acid ◽  
Xps Spectra

For exploiting green ecological cotton fiber products with the multifunction, a new cotton fiber crosslinked with chitosan of low molecular weight (CCCF) was prepared through the sodium periodate oxidation method. The reaction between amino groups of chitosan and aldehyde groups in the oxidized cotton cellulose occurred to obtain the CCCF in aqueous acetic acid solutions. The aldehyde group content in oxidized cotton cellulose increased markedly with the sodium periodate concentration, and the maximum weight gain of chitosan introduced on cotton fiber was 11.63% of the weight of cotton fibers. Furthermore, the crosslinking properties were respectively investigated by measurements of FT-IR and XPS spectra, the analysis indicated that the chitosan molecule was crosslinked on the surface of cotton fiber by the C=N covalent bond. This resulting CCCF is a novel ecological fiber and has more abilities of potential modification, which suggested useful information in planning applications for these modified cotton fibers.

Degradation control of cellulose scaffold by Malaprade oxidation

2014 ◽  
Vol 1621 ◽  
pp. 191-196
Author(s):  
Wichchulada Konkumnerd ◽  
Suong-Hyu Hyon ◽  
Kazuaki Matsumura
Keyword(s):  
Amino Acid ◽  
Acid Solution ◽  
Room Temperature ◽  
Sodium Periodate ◽  
Periodate Oxidation ◽  
Oxidized Cellulose ◽  
Amino Groups ◽  
Amino Acid Solution ◽  
Before And After ◽  
Aldehyde Groups

ABSTRACTStudy on oxidizing cellulose scaffold to dialdehyde cellulose by sodium periodate (NaIO4) was carried out. Concentration of sodium periodate and the reaction time were effected for aldehyde introduction to cellulose scaffolds. Cellulose powder was dissolved in 1-butyl-3-methylimidazolium chloride, an ionic liquid, at 100°C and maintained at room temperature for 7 days, providing flexible cellulose scaffold. The cellulose scaffold was oxidized using periodate oxidation (Malaprade oxidation), which oxidizes carbohydrate by glycol cleavage to provide dialdehyde. Aldehyde groups introduced into cellulose were quantified by simple iodometry. Oxidized cellulose scaffold was degraded in the amino acid solution triggered by the reaction between aldehyde groups and amino groups. During immersion of the cellulose scaffolds in the amino acid solution, the mass loss of the scaffolds was evaluated by measuring of weight of oxidized cellulose scaffold before and after degradation.

scholarly journals Sprouting of Sorghum (Sorghum bicolor [L.] Moench): Effect of Drying Treatment on Protein and Starch Features

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 407 ◽  
Author(s):  
Mia Marchini ◽  
Alessandra Marti ◽  
Claudia Folli ◽  
Barbara Prandi ◽  
Tommaso Ganino ◽  
...  
Keyword(s):  
Food Production ◽  
Cost Effective ◽  
High Exposure ◽  
Effective Technology ◽  
Drying Treatment ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The One ◽  
Drying Conditions ◽  
Sorghum Bicolor L

The nutritional and physicochemical properties of sorghum proteins and starch make the use of this cereal for food production challenging. Sprouting is a cost-effective technology to improve the nutritional and functional profile of grains. Two drying treatments were used after sorghum sprouting to investigate whether the drying phase could improve the protein and starch functionalities. Results showed that the drying treatment at lower temperature/longer time (40 °C for 12 h) extended the enzymatic activity that started during sprouting compared to the one performed at higher temperature/shorter time (50 °C for 6 h). An increased protein hydrolysis and water- and oil-holding capacity were found in the flour obtained by the former treatment. Higher protein matrix hydrolysis caused high exposure of starch to enzymes, thus increasing its digestibility, while worsening the technological functionality. Overall, modulating drying conditions could represent a further way, in addition to sprouting, to improve sorghum flour’s nutritional profile.

MICROSTRUCTURAL EVOLUTION OF Al-Cu-Mg-Ag ALLOY WITH TRACE Zr ADDITION DURING TWO-STEP HOMOGENIZATION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 855-862 ◽  
Author(s):  
FEIYUE MA ◽  
ZHIYI LIU
Keyword(s):  
Melting Point ◽  
Grain Boundaries ◽  
Microstructural Evolution ◽  
Cast Alloy ◽  
Scanning Calorimetry ◽  
Zr Addition ◽  
Homogenization Time ◽  
The Matrix ◽  
Higher Temperature ◽  
Lower Temperature

The microstructural evolution in an Al - Cu - Mg - Ag alloy with trace Zr addition during homogenization treatment was characterized by Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS). It was shown that the low-melting-point phase segregating toward grain boundaries is Al 2 Cu , with a melting point of 523.52°C. A two-step homogenization process was employed to optimize the microstructure of the as-cast alloy, during which the alloy was first homogenized at a lower temperature, then at a higher temperature. After homogenized at 420°C for 6 h, Al 3 Zr particles were finely formed in the matrix. After that, when the alloy was homogenized at an elevated temperature for a longer time, i.e., 515°C for 24 h, most of the precipates at the grain boundaries were removed. Furthermore, the dispersive Al 3 Zr precipitates were retained, without coarsening greatly in the final homogenization step. A kinetics model is employed to predict the optimal homogenization time at a given temperature theoretically, and it confirms the result in present study, which is 420°C/6h+515°C/24h.

scholarly journals Research on the Static Recrystallization and Precipitation Behaviors of a V-N Microalloyed Steel

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Baochun Zhao ◽  
Tan Zhao ◽  
Guiyan Li ◽  
Qiang Lu
Keyword(s):  
Static Recrystallization ◽  
Microalloyed Steel ◽  
Time Interval ◽  
Main Role ◽  
Recrystallization Process ◽  
Compression Tests ◽  
Double Compression ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Temperature Strain

Double compression tests were performed on a Gleeble-3800 thermomechanical simulator to study the softening behaviors of deformed austenite in a V-N microalloyed steel. The static recrystallization volume fractions were calculated by stress offset method, and the kinetic model of static recrystallization was constructed. The effects of temperature, strain, and time interval on the softening behaviors were analyzed, and the interactions between precipitation and recrystallization were discussed. The results show that the softening behaviors of the deformed austenite at lower temperature or higher temperature are markedly different. At the temperature of 850°C or 800°C, pinning effects of the precipitates play the main role, and the recrystallization process is inhibited, which leads to the formation of plateaus in the softening curves. An increase in strain promotes the precipitation and recrystallization processes while reduces the inhibition effect of precipitation on recrystallization as well.

Imine Bond Characterization and Properties for Controlled Release Drugs of Collagen Protein Cross-Linked Cotton Fiber

2011 ◽  
Vol 175-176 ◽  
pp. 214-219 ◽  
Author(s):  
Yun Hui Xu ◽  
Zhao Fang Du ◽  
Yu Yue Chen
Keyword(s):  
Controlled Release ◽  
Cotton Fiber ◽  
Sodium Periodate ◽  
Covalent Bond ◽  
Subsequent Treatment ◽  
Aqueous Acetic Acid ◽  
Cotton Thread ◽  
Collagen Protein ◽  
Ft Ir ◽  
Imine Bond

For exploiting the novel multifunctional ecological cotton fibers, a new cotton fiber with the collagen protein cross-linking (CPCCF) was prepared by the limited selective oxidation of a cotton thread with sodium periodate solution and subsequent treatment with a solution of collagen protein at 40°C in aqueous acetic acid. FT-IR spectra of the CPCCF suggested that the imine covalent bond between the collagen protein and the oxidized cotton fiber was formed through a series of reaction. X-ray diffractograms analysis showed that the crystallinity of oxidized cotton fiber after collagen protein treatment increased slightly. Meanwhile, Scanning electron microscopy photographs illuminated that the modification with collagen protein occurred on the surface of cotton fiber. Kjeldahl nitrogen analysis of the CPCCF showed that the maximum percentage of collagen protein introduced into cotton fiber was 1.68% (w/w). However, the breaking strength of the cotton thread oxidized partially by sodium periodate at the concentration of less than 2.0 mg ml-1 did not decrease much. Furthermore, a model experiment for the controlled release drugs was performed using aloe anthraquinone, components of a Chinese medicine, suggested potential usefulness of the CPCCF as a carrier for the controlled release drugs.

Effects of Sr Addition on Mechanical Properties and Microstructure of Mg-6Al Magnesium Alloy

2011 ◽  
Vol 686 ◽  
pp. 120-124
Author(s):  
Jin Ping Fan ◽  
She Bin Wang ◽  
Bing She Xu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Strengthening Mechanism ◽  
Microstructure And Mechanical Properties ◽  
Higher Temperature ◽  
Lower Temperature

The effects of Sr addition on the mechanical properties and microstructure of Mg-6Al mag- nesium alloy both at 25 °C and at 175 °C were investigated by means of OM, SEM and EDS and XRD. Upon the Sr addition of 2%, the tensile strength was increased by 7.2% to 184.4MPa at 25 °C, while it was increased by 30% to 155.4MPa at 175 °C. The strengthening mechanism of Mg-6Al-xSr at lower temperature (25 °C) was different from that at higher temperature (175°C). The results show that the addition of strontium effectively improved the microstructure and mechanical properties of magnesium alloy.

The Effect of Uniaxial Cyclic Deformation on the Evolution of Phase Transformation Fronts in Pseudoelastic NiTi Wire

2001 ◽  
Author(s):  
Mark A. Iadicola ◽  
John A. Shaw
Keyword(s):  
Mechanical Response ◽  
Infrared Imaging ◽  
Partial Transformation ◽  
Niti Wire ◽  
Full Field ◽  
Temperature Experiment ◽  
Background Temperature ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Niti Wires

Abstract Experiments are presented of the response of pseudoelastic NiTi wires subjected to displacement controlled cycles. A custom built thermo-mechanical testing apparatus is used to control the background temperature field of the wire specimen while allowing the evolution of transformation fronts to be tracked by full field infrared imaging. Two experiments under similar end-displacement histories, but at temperatures ≈8°C apart, are shown to give remarkably different cyclic responses. The mechanical response for the lower temperature experiment continued to soften but retained its shape through 43 partial transformation cycles, and the pattern of transformation fronts seemed to reach a steady state. The response for the higher temperature experiment showed a change in shape of the mechanical response and distinct changes in transformation front patterns over 31 partial transformation cycles.

A Numerical Analysis of Gas Turbine Disks Incorporating Rotating Heat Pipes

2000 ◽  
Author(s):  
Y. Cao ◽  
J. Ling ◽  
R. Rivir ◽  
C. MacArthur
Keyword(s):  
Heat Pipe ◽  
Gas Turbine ◽  
Heat Pipes ◽  
High Heat ◽  
Thermal Dissipation ◽  
High Heat Flux ◽  
Heating And Cooling ◽  
Turbine Disks ◽  
Higher Temperature ◽  
Lower Temperature

Abstract Radially rotating heat pipes have been proposed for cooling gas turbine disks working at high temperatures. A disk incorporating the heat pipe would have an enhanced thermal dissipation capacity and a much lower temperature at the disk rim and dovetail surface. In this paper, extensive numerical simulations have been made for heat-pipe-cooled disks. Thermal performances are compared for the disks with and without incorporating the heat pipe at different heating and cooling conditions. The numerical results presented in this paper indicate that radially rotating heat pipes can significantly reduce the maximum and average temperatures at the disk rim and dovetail surface under a high heat flux working condition. In general, the maximum and average temperatures at the disk rim and dovetail surface could be reduced by above 250 and 150 degrees, respectively, compared to those of the disk without the heat pipe. As a result, a disk incorporating radially rotating heat pipes could alleviate temperature-related problems and allow a gas turbine to work at a much higher temperature.

The Self-Decay Characteristics of Chlorine Dioxide in Water

2012 ◽  
Vol 610-613 ◽  
pp. 296-299
Author(s):  
Xin Jie Li ◽  
Dan Nan Jiang ◽  
Yue Jun Zhang
Keyword(s):  
Rate Constants ◽  
Tap Water ◽  
Pure Water ◽  
Decay Behaviour ◽  
Increase With Increase ◽  
Higher Temperature ◽  
Effects Of Temperature ◽  
Lower Temperature ◽  
Kinetics Of ◽  
Temperature Water

In order to learn the ClO2 decay behaviour in tap water, the kinetics of ClO2 decay in pure water was studied. Under the conditions of tap water treatment and keeping away from light, the effects of temperature and pH on ClO2 degradation were investigated. The results show that the ClO2 decay reaction in pure water is the first-order with respect to ClO2, the decay rate constants increase with increase in temperature or pH. At pH=6.87, the rate constants are 0.012h-1(15°C), 0.017h-1(25°C), 0.023h-1(35°C), and 0.029h-1(45°C), respectively. At 25°C, the rate constants are 0.0083h-1(pH=4.5), 0.0111h-1(pH=5.5), 0.0143h-1(pH=6.5), 0.0222h-1(pH=7.5), and 0.0351h-1(pH=8.5), respectively. The experimental data prove that ClO2 is more stable in acidic or lower temperature water than in neutral, alkalescent, or higher temperature water.

Sign in / Sign up

Export Citation Format

Share Document