Thermal Stability of Oxygen-Containing Functional Groups on Activated Carbon Surfaces in a Thermal Oxidative Environment

2014 ◽  
Vol 47 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Liqing Li ◽  
Xiaolong Yao ◽  
Hailong Li ◽  
Zheng Liu ◽  
Weiwu Ma ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Activated Carbon ◽  
Functional Groups ◽  
Carbon Surfaces ◽  
Thermal Stability Of

scholarly journals Preparation of Mesoporous Activated Carbon from Jackfruit PPI-1 Waste and Development of Different Surface Functional Groups

2015 ◽  
Vol 54 ◽  
pp. 189-200
Author(s):  
T.V. Nagalakshmi ◽  
K.A. Emmanuel ◽  
Ch. Suresh Babu ◽  
Ch. Chakrapani ◽  
P. Paul Divakar
Keyword(s):  
Activated Carbon ◽  
Functional Groups ◽  
Activated Carbons ◽  
Morphological Changes ◽  
Bet Surface Area ◽  
Surface Functional Groups ◽  
Phase Oxidation ◽  
Different Temperatures ◽  
Activating Agent ◽  
Thermal Stability Of

Jackfruit PPI-1 variety was selected as source of lignocellulose material. Its rind and pulp waste was used as precursor for preparation of activated carbon. K2CO3 was selected as activating agent to prepare activated carbon. Various carbons were prepared by changing the impregnation ratio (IR) at different temperatures. Activated carbon prepared at 600°C and at IR1 had good BET surface area (987m2 g-1) and yield (61.97%). In order to introduce different functional groups, this carbon was divided into two parts. One part was subjected to liquid phase oxidation with 0.1N HNO3 and the other part was soaked in 0.1N KOH for 3hours. SEM, FTIR, TPD, XRD and TGA analyses were done to identify surface morphological changes, nature of functional groups and thermal stability of activated carbons.

scholarly journals FUNCTIONALIZATION OF CELLULOSE AND CHITOSAN IN IONIC LIQUIDS

2020 ◽  
Vol 54 (9-10) ◽  
pp. 857-868
Author(s):  
CRISTINA STEFANESCU ◽  
WILLIAM H. DALY ◽  
IOAN I. NEGULESCU
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Functional Groups ◽  
Phthalic Anhydride ◽  
Reaction Products ◽  
Molar Ratios ◽  
Thermal Stability Of ◽  
Mechanisms Of Reactions

Chemistry of cellulose in ionic liquids has been briefly reviewed and, accordingly, the phthalation of chitosan in these ionic solvents has been investigated. Chitosan (K) has been reacted at 100 °C for 4 hours with phthalic anhydride (PA) in ionic liquids 1-butyl-3-methylimidazolium acetate (BMIMAc) and 1-butyl-3-methylimidazolium chloride (BMIMCl) in the presence of bases, pyridine and 1,4-diazobicyclo[2.2.2] octane (DABCO), or the phthalation has been catalyzed by N-bromosuccinimide (NBS). Depending on the nature of the reaction components, the samples were prepared with molar ratios of PA to anhydroglucose unit (PA:K) from 3:1 to 10:1, including molar ratios of bases or catalyst to chitosan, ranging also from 3:1 to 10:1. All the reaction products were soluble in dimethyl sulfoxide and dimethylformamide. Both functional groups of chitosan units, -OH and -NH2 , reacted, resulting in FTIR confirmed products containing esters, amide, and imide functional groups. Heating the isolated phthalated chitosan products to 200 °C led to cyclization with the formation of imide groups and elimination of water. When bases controlled the reactions, the highest degrees of substitution of DABCO product (DS = 0.80) was slightly higher than the highest DC of the reaction products obtained in the presence of pyridine (DS = 0.77). However, the presence of the Nbromosuccinimide catalyst in the system led to an increase of the degree of substitution of the functional groups of chitosan (DS = 1.75), compared with that listed above for the products resulted when the reactions were carried out in the presence of bases. The thermal stability of the chitosan derivatives obtained in the presence of a base depended primarily upon the nature of the counter ion of the ionic liquid. When the reaction was conducted in the acetate ionic liquid BMIMAc, the phthalated chitosan exhibited a lower thermal stability than that of chitosan, while when the chloride ionic liquid BMIMCl was used as solvent, the thermal stability of the phthalated chitosan increased, indicating an interference of the ionic solvents in the mechanisms of reactions. Nevertheless, the thermal behavior of the phthalated products obtained in reactions catalyzed by NBS may be correlated with the increasing degrees of substitution achieved with increased catalyst concentrations: a higher DS resulted in a higher weight loss at higher temperatures.

Thermal stability of perfluorinated molecular monolayers immobilized on pulsed laser deposited amorphous carbon surfaces

2010 ◽  
Vol 16 ◽  
pp. 012003 ◽  
Author(s):  
Christian Godet ◽  
Hussein Sabbah ◽  
Marie Hervé ◽  
Soraya Ababou-Girard ◽  
Stéphanie Députier ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Amorphous Carbon ◽  
Pulsed Laser ◽  
Molecular Monolayers ◽  
Carbon Surfaces ◽  
Thermal Stability Of

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Microstructure studies of tungsten silicide schottky contacts on Gaas

1987 ◽  
Vol 45 ◽  
pp. 328-329
Author(s):  
Yih-Cheng Shih ◽  
E. L. Wilkie
Keyword(s):  
Thermal Stability ◽  
Field Effect Transistors ◽  
Schottky Contact ◽  
Schottky Contacts ◽  
Excellent Thermal Stability ◽  
Barrier Heights ◽  
Gaas Substrates ◽  
Film Adhesion ◽  
Threshold Voltages ◽  
Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

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