scholarly journals Two-Stage Plasma-Thermal Nitridation Processes for the Production of Aluminum Nitride Powders from Aluminum Powders

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 359 ◽  
Author(s):  
Mei-Chen Sung ◽  
Ya-Fen Wang ◽  
Shang-Che Chen ◽  
Cheng-Hsien Tsai
Keyword(s):  
Reaction Time ◽  
Aluminum Nitride ◽  
Reaction Temperature ◽  
Mass Production ◽  
Microwave Plasma ◽  
Synthesis Process ◽  
Sem Images ◽  
Nitridation Process ◽  
Low Efficiency ◽  
Thermal Nitridation

The synthesis of aluminum nitride (AlN) powders is traditionally done via the thermal nitridation process, in which the reaction temperature reaches as high as 960 °C, with more than several hours of reaction time. Moreover, the occurrence of agglomeration in melting Al particles results in poor AlN quality and a low efficiency of nitridation. In this study, an atmosphere-pressure microwave-plasma preceded the pre-synthesis process. This process operates at 550 °C for 2–10 min with the addition of NH4Cl (Al: NH4Cl = 1:1) for generating a hard AlN shell to avoid the flow and aggregation of the melting Al metals. Then, the mass production of AlN powders by the thermal nitridation process can be carried out by rapidly elevating the reaction temperature (heating rate of 15 °C/min) until 1050 °C is reached. X-Ray Diffractometer (XRD) crystal analysis shows that without the peak, Al metals can be observed by synthesizing AlN via plasma nitridation (at 550 °C for 2 min, Al: NH4Cl = 1:1), followed by thermal nitridation (at 950 °C for 1 h). Moreover, SEM images show that well-dispersed AlN powders without agglomeration were produced. Additionally, the particle size of the produced AlN powder (usually < 1 μm) tends to be reduced from 2–5 μm (Al powders), resulting in a more efficient synthesizing process (lower reaction temperature, shorter reaction time) for mass production.

Rapid Synthesis of Aluminum Nitride Nanopowders from Gaseous Aluminum Chloride

2020 ◽  
Vol 862 ◽  
pp. 88-93
Author(s):  
Fu Lin Chu ◽  
Lai Wang Wang ◽  
Meng Yung Sun ◽  
Cheng Hsien Tsai
Keyword(s):  
Aluminum Nitride ◽  
Aluminum Chloride ◽  
Microwave Plasma ◽  
Resonant Cavity ◽  
Gas Content ◽  
Synthesis Process ◽  
Plasma Chemical ◽  
Aluminum Powders ◽  
Low Efficiency ◽  
Thermal Nitridation

The synthesis of aluminum nitride (AlN) powders is traditionally completed through a thermal nitridation process, in which the reacting aluminum powders are combined with nitrogen at high temperatures with a long reaction time (usually several hours). Moreover, the occurrence of agglomeration within the melting Al particles results in a poor dispersibility of AlN powders, with a low efficiency of nitridation. In this study, an atmosphere-pressure microwave plasma preceded the rapid gas-gas synthesis process. In the reactor, the gaseous aluminum chloride (AlCl3) reactant was fed at different positions (R1, R2, R3) to react with nitrogen at various reaction temperatures (690~1150°C) to rapidly produce AlN nano powders (in several seconds). The process was operated at a total flow rate of 13 slm with NH3 gas content of 0 or 0.77% and an applied power of 1200/1400 W. Results showed that the high purity and dispersibility of AlN powders were found at a AlCl3 feeding position closer to the resonant cavity of the reactor (R3, 1150°C). The AlN particle size was in the range of 25-50 nm. The experiments indicated that the gas-gas reaction for rapidly synthesizing AlN nanopowders can be successfully carried out via an AlCl3-N2 plasma-chemical approach.

Optimization of Synthesis Process for Sodium Ascorbate

2012 ◽  
Vol 550-553 ◽  
pp. 10-15 ◽  
Author(s):  
Jing Chen Wang ◽  
Feng Xia Cui ◽  
Tao Li
Keyword(s):  
Reaction Time ◽  
Sodium Carbonate ◽  
Reaction Temperature ◽  
Conversion Rate ◽  
Sodium Ascorbate ◽  
Synthesis Process ◽  
Esterification Reaction ◽  
Reaction Yield ◽  
Process Conditions ◽  
Reactant Ratio

With 2-keto-L-gulonic acid(2KLG) and methanol as raw materials, 98% concentrated sulfuric acid as catalyst, the methyl esterification reaction is occurred. Then with sodium carbonate as a transforming agent, a conversion reaction sodium carbonate is obtained. In this experiment, the effects of reaction time, reaction temperature and reactant ratio on conversion rate of sodium ascorbate were studied. The results showed that sodium carbonate as the reactant of lactonization reaction can effectively shorten the reaction time and improve reaction yield. By experiment under the optimum process conditions: the reaction temperature is 65 °C, reaction time is 150 minutes and the molar ratio of 2-keto-L-gu methyl to sodium carbonate is 1:0.6, the conversion rate reaches 98 % and the effect is better than with sodium bicarbonate as transforming agent.

scholarly journals Investigation on the Synthesis Process of Bromoisobutyryl Esterified Starch and Its Sizing Properties: Viscosity Stability, Adhesion and Film Properties

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1936
Author(s):  
Wei Li ◽  
Jie Wu ◽  
Zhengqiao Zhang ◽  
Lanjuan Wu ◽  
Yuhao Lu
Keyword(s):  
Reaction Time ◽  
Polylactic Acid ◽  
Process Parameters ◽  
Reaction Temperature ◽  
Graft Copolymers ◽  
Degree Of Crystallinity ◽  
Synthesis Process ◽  
Film Properties ◽  
Breaking Elongation ◽  
Viscosity Stability

To confirm the suitable synthesis process parameters of preparing bromoisobutyryl esterified starch (BBES), the influences of the synthesis process parameters—amount of 2-bromoisobutyryl bromide (BIBB), amount of catalyst (DMAP), reaction temperature and reaction time—upon the degree of substitution (DS) were investigated. Then, to produce a positive effect on the properties of graft copolymers of BBES prepared in the near future, a series of BBES samples were successfully prepared, and their sizing properties, such as apparent viscosity and viscosity stability, adhesion, and film properties, were examined. The BBES granules were characterized by Fourier transform infra-red spectroscopy and scanning electron microscopy. The adhesion was examined by determining the bonding forces of the sized polylactic acid (PLA) and polyester roving. The film properties were investigated in terms of tensile strength, breaking elongation, degree of crystallinity, and cross-section analysis. The results showed that a suitable synthesis process of BBES was: reaction time of 24 h, reaction temperature of 40 °C, and 0.23 in the molar ratio of 4-dimethylaminopyridine to 2-bromoisobutyryl bromide. The bromoisobutyryl esterification played the important roles in the properties of the starch, such as paste stabilities of above 85% for satisfying the requirement in the stability for sizing, improvement of the adhesion to polylactic acid and polyester fibers, and reduction of film brittleness. With rising DS, bonding forces of BBES to the fibers increased and then decreased. BBES (DS = 0.016) had the highest force and breaking elongation of the film. Considering the experimental results, BBES (DS = 0.016) showed potential in the PLA and polyester sizing, and will not lead to a negative influence on the properties of graft copolymers of BBES.

Fabrication and Analysis of β-Sialon Whiskers from Fly Ash by Carbon Thermal Reduction-Nitridation

2015 ◽  
Vol 723 ◽  
pp. 610-614
Author(s):  
Jing Zhang ◽  
Jiang Long Yu ◽  
Huan Zhao ◽  
Jun Shuai Liu
Keyword(s):  
Fly Ash ◽  
Reaction Time ◽  
Carbon Content ◽  
Reaction Temperature ◽  
Carbothermal Reduction ◽  
Thermal Reduction ◽  
Optimal Temperature ◽  
Nitridation Process ◽  
Best Parameter ◽  
Sialon Powder

β-Sialonwhiskers which the molecular structuralformula of β-Sialonis Si3Al3O3N5(z = 3) were synthesized from fly ash and graphite under appropriate technological conditions by carbothermal reduction–nitridation process. The effects of carbon content, reaction temperature and reaction time on synthesis ofβ-Sialonwere analysed by XRD, SEM techniques. The results proved that, the condition of the carbon content over 80% is the best parameter to promote theβ-Sialon powder production. Compared to other kinds of temperature, 1430 °C is the optimal temperature to promoteβ-Sialon powder generation. Compared to 3h, holding time of 6h is promoting theβ-Sialon powder generation.The main morphology of β-Sialon was rod-like whisker.

Research of Catalytic Oxidation Synthesis of Cyclopentene to Glutaraldehyde

2011 ◽  
Vol 391-392 ◽  
pp. 1149-1152
Author(s):  
Qi Dong Yan ◽  
Jun Xu ◽  
Feng Xu
Keyword(s):  
Reaction Time ◽  
Catalytic Oxidation ◽  
Reaction Temperature ◽  
Influence Factors ◽  
Synthesis Process ◽  
Mass Ratio ◽  
Tertiary Butanol ◽  
Catalyst Dosage ◽  
Main Influence ◽  
Oxidation Synthesis

The paper has studied the process of using H2O2 as oxidant and tungsten acid as catalyst, catalytic oxidation synthesis process of cyclopentene to glutaraldehyde and explored the main influence factors of the reaction, including the reaction time, reaction temperature, catalyst dosage and solvent. Furthermore, the quantitative analysis and qualitative analysis of the product was characterized by gas chromatography. The optimum synthetic condition was as follows: tertiary butanol as solvent, tungsten acid: boron anhydride(mass ratio)=1:1, 30%H2O2 as oxidant, the reaction temperature 35°C, the reaction time 4h, the yield of glutaraldehyde yield was 46%.

Research on the Synthetic of Silicone Emulsion

2013 ◽  
Vol 826 ◽  
pp. 233-236
Author(s):  
Rui Mu ◽  
Cui Hua Ji
Keyword(s):  
Molecular Weight ◽  
Reaction Time ◽  
Emulsion Polymerization ◽  
Influencing Factors ◽  
Reaction Temperature ◽  
Conversion Rate ◽  
Synthesis Process ◽  
Weight Increment ◽  
Silicone Emulsion

This study synthesized silicon emulsions by emulsion polymerization, mainly focused on how influencing factors including catalyst, emulsifier, reaction temperature and synthesis process could affect product conversion rate, appearance and molecular weight. The result showed that the conversion rate of the first 2 hours increased rapidly and became stable afterwards. Molecular weight increment was proportional to the extension of the reaction time. The silicon emulsions could achieve high convention rate and stability while applying 5% catalyst DBSA and 3% emulsifier (OP-10: SDS = 1:2) of Octmethyl cyclotetrasiloxane(D4) under an reaction temperature of 80 °C.

scholarly journals Polyvinyl Butyral Synthesis Process Based on Deep Eutectic Solvent as a Catalyst

2021 ◽  
pp. 31-39
Author(s):  
Po Li ◽  
Weilan Xue ◽  
Zuoxiang Zeng ◽  
Li Sun ◽  
Yu Bai
Keyword(s):  
Reaction Time ◽  
Low Temperature ◽  
Reaction Temperature ◽  
Raw Materials ◽  
Condensation Reaction ◽  
Deep Eutectic Solvent ◽  
Polyvinyl Butyral ◽  
Synthesis Process ◽  
Temperature Reaction ◽  
Mass Ratio

Polyvinyl butyral (PVB) was prepared by the condensation reaction of polyvinyl alcohol (PVA) with n-butyraldehyde using a catalyst which is a kind of deep eutectic solvent (DES) made of dodecyltrimethylammonium chloride and p-toluenesulfonic acid. The raw materials and products were characterized by Fourier transform infrared spectroscopy (FT-IR). The effects of the following reaction conditions on the degree of PVB acetal, yield and agglomeration of the products were investigated: the mass ratio of n-butyraldehyde to PVA (mBA/mPVA) of 0.48-0.96, the mass ratio of catalyst to PVA (mcat/mPVA) of 0.16-0.64, the low temperature reaction temperature (5-20℃), and the low temperature reaction time (1-3h). The results showed that at mBA/mPVA =0.8, mcat/mPVA =0.32, low temperature reaction temperature of 15°C and low temperature reaction time of 2 hours, the obtained PVB was a homogeneous powder with the highest acetal degree of 73.85%.

Study on Industry Process of the Rubber Anti-Oxidant RD

2011 ◽  
Vol 79 ◽  
pp. 99-104
Author(s):  
Yu Liu ◽  
Qin Yu Gao ◽  
Lian Xin Liu ◽  
Guang Xia Shi
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Concentration Ratio ◽  
Design Method ◽  
Orthogonal Design ◽  
Yield Stability ◽  
Synthesis Process ◽  
Reaction Condition ◽  
Orthogonal Design Method ◽  
Anti Oxidant

This paper studied on the industry synthesis process of anti-oxidant RD ((2,2,4- trimethyl-1,2-dihydro- quinoline polymer (C12H15N)n.n=2-4)) .The content of dimer, trimer and tetramer of RD were taken as the inspection targets, used the orthogonal design method, and take the ratios of keto-amine, the reaction time, the reaction temperatures and the ratios of catalyst acid-amine as inspect factors to optimized reaction condition. The result indicated that the best ratio of keto-amine is 6.5:1, the reaction time is 6 hours, the range of the reaction temperature is 115-120°C, the beat ratio of acid-amine is 0.2: 1 (the proportion is the concentration ratio for mole). Under the optimization conditions, the yield stability of RD.

scholarly journals Synthesis of lignin-based phenol-formaldehyde adhesive - A sustainable alternative to petrochemical

2021 ◽  
Vol 13 (3) ◽  
pp. 48-57
Author(s):  
Thi Nhu Y Nguyen ◽  
Thi Yen Nhi Nguyen ◽  
Thi Minh Thu Tran ◽  
Thi Ven Nguyen ◽  
Nguyen Phuong Lan Tran ◽  
...  
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Bending Strength ◽  
Phenol Formaldehyde ◽  
Tensile Modulus ◽  
Mekong Delta ◽  
Solid Content ◽  
Synthesis Process ◽  
Scanning Calorimetry ◽  
Synthetic Process

This study is to investigate the capability of producing lignin-based phenol-formaldehyde adhesive (LBPFA) with lignin derived from coir pith collected in the Mekong Delta, Viet Nam. The LBPFA synthetic process underwent non chemical modifications to minimize petrochemicals and energy. Effective factors as reaction time, reaction temperature and various lignin contents of phenol substitution were examined. Physical, chemical and thermal properties containing formaldehyde content, viscosity, solid content, Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), tensile strength, tensile modulus and tensile strain were conducted. LBPFA was successfully synthesized at various levels of lignin contents substituting for phenol. The LBPFA’s parameters were in accordance with GB/T14372-2006 standard. The optimum reaction time, reaction temperature and lignin replacement content for LBPFA synthesis process were identified at 180 minutes, 900C and 40% wt/wt, respectively. The LBPFA showed the highest dry and wet tensile strengths of 14.42 MPa and 7.66 MPa on wooden boards compared to corresponding figures of commercial resin with 2.98 MPa and 0 MPa, respectively. For plywood, bending strength shown in LBPFA and commercial adhesive were 15.97 MPa and 20.16 MPa, respectively.

scholarly journals Optimization and modeling of reactive conditions for free radical solution polymerization of SA-co-BA copolymer based on the yield using response surface methodology

2021 ◽  
Vol 17 (1) ◽  
pp. 50-55
Author(s):  
Basem Elarbe ◽  
Ibrahim Elganidi ◽  
Norhayati Abdullah ◽  
Kamal Yusoh ◽  
Norida Ridzuan
Keyword(s):  
Response Surface Methodology ◽  
Free Radical ◽  
Reaction Time ◽  
Regression Model ◽  
Response Surface ◽  
Reaction Temperature ◽  
Maximum Yield ◽  
Synthesis Process ◽  
Yield Response ◽  
Solution Polymerization

In the recent years, response surface methodology (RSM) is one of the most common optimization methods employed in the chemical process. The satisfactory model for predicting the maximum yield in solution polymerization has been a challenge due to various conditions during the synthesis process. In this study, interactive impacts of three parameters which are reaction time, concentration of initiator, and reaction temperature on the yield in free radical polymerization of SABA copolymer using toluene as solvent was investigated using experimental design central composite design (CCD) model under response surface methodology (RSM). The result showed the optimization conditions were reaction time of 7 h, initiator concentration of 1 wt %, and reaction temperature of 90 oC with the corresponding yield of 97.31%. The analysis of the regression model (ANOVA) detected an R2 value of 0.9844, that the model is able to clarify 98.44% of the data variation, and just 1.23% of the whole differences is not clarified by the model. Three experimental validation runs were carried out using the optimal replicate conditions and the highest average yield value obtained is 97.15%. There is an error of about 0.97% as compared to the expected value.Therefore, the results indicate that this model is reliable and is able to predict the yield response accurately. it established that the regression model is extremely significant, indicating a strong agreement between the expected and the experimental values of SABA yield.

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