scholarly journals The Synthesis Process and Thermal Stability of V2C MXene

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2112 ◽  
Author(s):  
Meng Wu ◽  
Bingxin Wang ◽  
Qianku Hu ◽  
Libo Wang ◽  
Aiguo Zhou
Keyword(s):  
Thermal Stability ◽  
Hydrochloric Acid ◽  
Vanadium Carbide ◽  
Potassium Fluoride ◽  
Synthesis Process ◽  
Three Solutions ◽  
Etching Solution ◽  
Air Atmosphere ◽  
Vanadium Trioxide ◽  
Thermal Stability Of

The effect of etching solution on the synthesis process of two-dimensional vanadium carbide (V2C MXene) was researched. Three etching solutions were used to etch ternary carbide V2AlC at 90 °C. The three solutions were: lithium fluoride + hydrochloric acid (LiF + HCl), sodium fluoride + hydrochloric acid (LiF + HCl), and potassium fluoride + hydrochloric acid (KF + HCl). It was found that only NaF + HCl solution was effective for synthesizing highly pure V2C MXene. The existence of sodium (Na+) and chloridion (Cl−) in etching solution was essential for the synthesis. The thermal stability of the as-prepared V2C MXene in argon or air was studied. From thermogravimetry and differential thermal analysis, V2C MXene was found to be stable in argon atmosphere at a temperature of up to 375 °C. As the temperature increased, V2C MXene was gradually oxidized to form nanoparticles composed of vanadium trioxide (V2O3) and a part of V2C MXene was broken and transformed to vanadium carbide (V8C7) at 1000 °C. In air atmosphere, V2C MXene was stable at 150 °C. At 1000 °C, V2C MXene was oxidized to form vanadium pentoxide (V2O5).

scholarly journals Phosphated Avocado Seed: A Renewable Biomaterial for Preparing a Flame Retardant Biofiller

2021 ◽  
Author(s):  
DAVID Zuluaga-Parra ◽  
L.F Ramos-deValle ◽  
Saul Sanchez ◽  
J.R. Torres-Lubián ◽  
J.A. Rodríguez-Gonzalez ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Chemical Modification ◽  
Flame Retardant ◽  
Photoelectron Spectroscopy ◽  
Morphological Changes ◽  
Ethylene Vinyl Acetate ◽  
Chemically Modified ◽  
Air Atmosphere ◽  
Thermal Stability Of ◽  
Avocado Seed

Abstract The cellulose and starch present in the avocado seed can be chemically modified to obtain biofillers with fire retarding characteristics. The resulting composites could be used as substitute of the corresponding halogenated composites. For this, the avocado seed was first washed, dehydrated and pulverized, and thereafter, chemically modified with phosphoric acid in the presence of urea. This was studied using infrared spectroscopy, nuclear magnetic resonance and X-Ray photoelectron spectroscopy, in order to determine the resulting chemical structure and confirm the presence of the proposed functional groups. In addition, scanning electron microscopy and elemental analysis were used, respectively, to establish the resulting morphological changes, as well as the elements present on the surface of the modified material. Thermogravimetric analysis was also carried out in order to establish the thermal stability of the material and predict the effect on the flame retardancy due to the mentioned chemical modification. Further tests established that the obtained modified structure and morphology of the avocado seed was highly dependent on the method used to dehydrate the pulverized avocado seed. It was also determined that chemical modification greatly increased the thermal stability of the avocado seed in air atmosphere. The flame-retardant effect of the modified avocado seed was assessed in polyethylene/ethylene-vinyl-acetate (PE/EVA) composites via cone calorimeter tests. These results showed that the modified avocado seed decreased the peak of the heat release rate (pHRR) by 50% and the total heat released (THR) by 15%. This phosphated avocado seed could be a good option as a renewable biofiller for polymer composites with enhanced flame-retardant properties.

scholarly journals Nitridated Ca2NaMg2V3O12: Eu3+ Vanadate Garnet Phosphor-in-Glass

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2996
Author(s):  
Damian Pasinski ◽  
Jerzy Sokolnicki
Keyword(s):  
Thermal Stability ◽  
Single Phase ◽  
Low Energy ◽  
Color Temperature ◽  
Garnet Structure ◽  
Air Atmosphere ◽  
Ammonia Atmosphere ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Emission Quantum Yield

In this study, Ca2NaMg2V3O12 coordination compound undoped and doped with Eu3+ obtained in the air and ammonia atmosphere by solid-state reaction was investigated. Ca2NaMg2V3O12: Eu3+ obtained in the ammonia atmosphere was then investigated as a phosphor-in-glass (PiG). Annealed Ca2NaMg2V3O12: Eu3+ phosphor forms a single phase with the cubic garnet structure and Ia3d space group. Nitridation in ammonia causes a widening of a VO43− group emission band on the low energy side and it red-shifts by 20 nm. The emission of Eu3+ is extended as compared to the non-nitridated phosphor. Ca2NaMg2V3O12: Eu3+ after nitridation shows higher emission quantum yield (QY): 49 vs. 45 and lower correlated color temperature (CCT) and 4179 vs. 4998 as compared to phosphor without nitridation. The QY for PiG is 55. The thermal stability of nitridated phosphors is superior to phosphor obtained in the air atmosphere and is further enhanced for PiG.

Thermal Stability, Structure and Mechanical Properties of TiSiN Coatings Prepared by Reactive DC Magnetron Co-Sputtering

2006 ◽  
Vol 509 ◽  
pp. 93-98 ◽  
Author(s):  
L. García-González ◽  
J. Morales-Hernández ◽  
F.J. Espinoza-Beltrán ◽  
J. Muñoz-Saldaña ◽  
T. Scholz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Crystallite Size ◽  
Flow Rate ◽  
Air Atmosphere ◽  
Corning Glass ◽  
Stability Structure ◽  
Nitrogen Ratio ◽  
Steel Substrates ◽  
Thermal Stability Of

TiSiN coatings have been prepared by reactive DC magnetron co-sputtering on Corning glass and carbon steel substrates, using Ti-Si targets, with a constant Si:Ti area ratio of 0.2. The flow rate of nitrogen has been varied from 1.6 to 7.0 sccm, for a fixed argon flow rate of 25.0 sccm. We present a study of structure (texture, crystallite size and microstrain), chemical composition, and mechanical properties of the coatings and their dependence on the argon/nitrogen ratio. Moreover, a study of the thermal stability of the coatings has been performed by means of thermal annealing under oxidizing conditions (air atmosphere) at 500 and 600 °C. Coatings with the smallest crystallite size (∼2 nm) present the highest hardness (26 GPa) and the best thermal stability.

Thermal Behavior Prediction of MDPE Nanocomposite/Cloisite Na+ Using Artificial Neural Network and Neuro-Fuzzy Tools

2010 ◽  
Vol 1 (4) ◽  
Author(s):  
J. Sargolzaei ◽  
B. Ahangari
Keyword(s):  
Neural Network ◽  
Thermal Stability ◽  
Artificial Neural Network ◽  
Thermal Behavior ◽  
Fuzzy Inference ◽  
Air Atmosphere ◽  
Artificial Neural ◽  
Artificial Neural Network Ann ◽  
Inference Systems ◽  
Thermal Stability Of

Recently, we successfully prepared medium density polyethylene (MDPE) nanocomposite with 3 wt %, 6 wt %, and 9 wt % cloisite Na+ and the thermal stability of nanocomposite was investigated using the thermogravimetric analysis (TGA). The TGA in air atmosphere showed significantly improved thermal stability of 3 wt %, 6 wt %, and 9 wt % cloisite Na+ nanocomposite in comparison to pure MDPE. In this paper, the results of TGA of MDPE/cloisite Na+ nanocomposites were predicted by the artificial neural network (ANN). The ANN and adaptive neural fuzzy inference systems (ANFIS) models were developed to predict the degradation of MDPE/cloisite Na+ nanocomposite with temperature. The results revealed that there was a good agreement between predicted thermal behavior and actual values. The findings of this study also showed that the artificial neural networks and ANFIS techniques can be applied as a powerful tool.

scholarly journals Thermal Stability and Flame Retardancy of Polypropylene Composites Containing Siloxane-Silsesquioxane Resins

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1019 ◽  
Author(s):  
Arkadiusz Niemczyk ◽  
Katarzyna Dziubek ◽  
Beata Sacher-Majewska ◽  
Krystyna Czaja ◽  
Justyna Czech-Polak ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Flame Retardancy ◽  
Cone Calorimeter ◽  
Flame Retardants ◽  
Infrared Spectrometry ◽  
Material Surface ◽  
Polypropylene Composites ◽  
Air Atmosphere ◽  
First Time ◽  
Thermal Stability Of

A novel group of silsesquioxane derivatives, which are siloxane-silsesquioxane resins (S4SQ), was for the first time examined as possible flame retardants in polypropylene (PP) materials. Thermal stability of the PP/S4SQ composites compared to the S4SQ resins and neat PP was estimated using thermogravimetric (TG) analysis under nitrogen and in air atmosphere. The effects of the non-functionalized and n-alkyl-functionalized siloxane-silsesquioxane resins on thermostability and flame retardancy of PP materials were also evaluated by thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) and by cone calorimeter tests. The results revealed that the functionalized S4SQ resins may form a continuous ceramic layer on the material surface during its combustion, which improves both thermal stability and flame retardancy of the PP materials. This beneficial effect was observed especially when small amounts of the S4SQ fillers were applied. The performed analyses allowed us to propose a possible mechanism for the degradation of the siloxane-silsesquioxane resins, as well as to explain their possible role during the combustion of the PP/S4SQ composites.

Investigation on the Continuous Microwave Synthesis of Nano Titanium Carbide Powder

2014 ◽  
Vol 1064 ◽  
pp. 66-70 ◽  
Author(s):  
Ling Ke Zeng ◽  
Yan Chun Liu ◽  
Wen Cheng Zhu ◽  
Ping An Liu ◽  
Hui Wang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Titanium Dioxide ◽  
Reaction Mechanism ◽  
Titanium Carbide ◽  
Microwave Synthesis ◽  
Inorganic Carbon ◽  
Synthesis Process ◽  
Carbide Powder ◽  
Thermal Stability Of ◽  
Thermodynamic Basis

In this paper, the reaction mechanism of inorganic carbon and titanium dioxide synthesis of titanium carbide thermodynamic were explored, and a thermodynamic basis date for the microwave heating was provided. Through analyzing the experimental results for the thermal stability of titanium carbide, we could obtain the theoretical parameters for the actual synthesis process.

Effect of CuO on the Thermal Stability of Polyaniline Nanofibers

2014 ◽  
Vol 12 (1) ◽  
pp. 215-221 ◽  
Author(s):  
Mohammad Mizanur Rahman Khan ◽  
Yee Keat Wee ◽  
Wan Ahmad Kamil Mahmood
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Composite Nanofibers ◽  
Direct Evidence ◽  
Synthesis Process ◽  
Polyaniline Nanofibers ◽  
Pani Nanofibers ◽  
Transmission Electron ◽  
Thermal Stability Of ◽  
Scanning Electron

Abstract Direct evidence of the control of thermal stability of polyaniline (PANI) nanofibers is reported by systematically varying the loadings of CuO in the synthesis process. The addition of Cu was maintained in the range from 0.005 g to 1.0 g. The freshly prepared PANI-CuO composite nanofibers were investigated by means of field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). TGA data showed that the thermal stability of PANI nanofibers was greatly improved when the CuO were added, except for the highest addition of CuO (1.00 g). We also found that 0.01 g loading of CuO is favorable to obtain comparatively more thermally stable PANI than the other amount. The degradation of PANI chains started at 360°C for the PANI-CuO composites obtained at 0.01 g CuO addition, which is the highest temperature compared to PANI and the samples synthesized at other amount of CuO loadings.

scholarly journals Investigating the Effect of Aluminum Diethylphosphinate on Thermal Stability, Flame Retardancy, and Mechanical Properties of Poly(butylene succinate)

2021 ◽  
Vol 8 ◽  
Author(s):  
Yiming Wang ◽  
Dayong Jiang ◽  
Xin Wen ◽  
Tao Tang ◽  
Karolina Szymańska ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Flame Retardancy ◽  
Oxygen Index ◽  
Butylene Succinate ◽  
Air Atmosphere ◽  
Cone Calorimeter Test ◽  
Filler Dispersion ◽  
Thermal Stability Of ◽  
Limited Oxygen

Poly(butylene succinate) is one of the most promising biodegradable polymers, but its applications are limited by poor flame retardancy. In this work, poly(butylene succinate)/diethylphosphinate (PBS/AlPi) composites were fabricated to investigate the effect of AlPi on their thermal stability, flame retardancy, and mechanical properties. It was found that the high content of AlPi decreased the thermal stability of PBS, and the decrease became stronger under the air atmosphere. When the content of AlPi reached 25wt%, the flame retardancy was improved with limited oxygen index (LOI) of 29.5%, V0 rating in UL-94 vertical burning test, and 49.3% reduction on the peak of heat release rate (PHRR) in cone calorimeter test. Meanwhile, the addition of AlPi could improve the mechanical properties of PBS with high tensile strength and Young’s modulus, which was ascribed to the compatible effect of maleic anhydride-grafted poly(butylene succinate) (PBS-g-MA) with good filler dispersion and strong matrix-particles interaction. Thus, the AlPi was an effective flame retardant to PBS, so that PBS/AlPi composites displayed excellent flame retardancy without seriously sacrificing other comprehensive performances.

Comparison study on the effect of acid and nitrate salt on the properties of poly(vinyl alcohol) coating doped with dye consist of anthocyanin

2015 ◽  
Vol 44 (4) ◽  
pp. 250-256
Author(s):  
S.V. Lee ◽  
R. Usop ◽  
A.N. Hadi ◽  
N.A. Mazni ◽  
S.R. Majid ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Hydrochloric Acid ◽  
Calcium Nitrate ◽  
Natural Dye ◽  
Poly Vinyl Alcohol ◽  
Nitrate Salt ◽  
Comparison Study ◽  
Coating Films ◽  
Content Type ◽  
Thermal Stability Of

Purpose – The purpose of this paper is to observe the thermal and colour stabilities of coating films consisting of natural dye anthocyanin colourant with acid and nitrate salt as additives. Design/methodology/approach – The natural dye was extracted from Hibiscus sabdariffa L. (Roselle) by using distilled water as solvent. The extracted dye was mixed with 1 weight per cent hydrochloric acid and 5 weight per cent calcium nitrate to conduct the comparison study. The dye samples were than mixed with poly (vinyl alcohol) (PVA). The mixtures were applied on glass panels to form coating films. The coating films were left to dry for 24 hours. The thermal stability of coating films was investigated by using thermogravimetric analysis (TGA). The amorphousness coating films molecular structures were observed by using x-ray diffraction (XRD). CIE L*a*b* colour coordinate space technique was used to investigate the coating films colour stability against ultraviolet (UV). Findings – The results show that addition of hydrochloric acid (HCl acid) enhanced thermal stability of PVA-anthocyanin coating and shifted the degradation temperature to higher temperature at 300°C. HCl acid also improved UV stability of the coating system significantly with the reduced ΔE from 26.67 to 16.89. Addition of calcium nitrate (Ca(NO3)2) salt promotes good interaction with PVA-anthocyanin system that caused structural changes, improved thermal stability and increased Tg from 61.5 to 83.1°C. Research limitations/implications – The potential of using natural dye extracted from plant as renewable material. Practical implications – The coating films developed in this works are suitable for glass substrate application. Originality/value – Development of water-based coating from PVA binder with anthocyanin colourant is introduced in this study.

Influence of Ammonium Hydroxide Treatment on Structural Stability of Polyaniline/Multi–Walled Carbon Nanotube Nanocomposites

2012 ◽  
Vol 557-559 ◽  
pp. 291-294
Author(s):  
Yue Tang ◽  
Zong Yi Qin ◽  
Na Liu
Keyword(s):  
Thermal Stability ◽  
Aqueous Solution ◽  
Hydrochloric Acid ◽  
Structural Stability ◽  
Ammonium Hydroxide ◽  
Low Molecular Weight ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Thermal Stability Of

The composites consisting of multi–walled carbon nanotubes (MWCNTs) core and polyaniline (PANI) shell were prepared in aqueous solution of hydrochloric acid, and then a de–doping process was achieved through a simple ammonium hydroxide (NH4OH) treatment. The influences of NH4OH treatment on the morphology, microstructure and thermal stability of the as–prepared composites were studied. It is found that after the removal of hydrochloric acid (HCl) as a volatile dopant and the low molecular weight components, structural stability of the treated composite could be achieved, leading to a significant enhancement on thermal properties.

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