Thermal degradation of organic additives used in colloidal shaping of ceramics investigated by the coupled DTA/TG/MS analysis
01 Feb 2016-Journal of Thermal Analysis and Calorimetry (Springer Netherlands)-Vol. 123, Iss: 2, pp 1419-1430
TL;DR: In this paper, the analysis of thermal decomposition of selected organic additives, which are commonly used in shaping of ceramic materials by colloidal methods, was performed on an apparatus coupled with a mass spectrometer.
Abstract: The paper presents the analysis of thermal decomposition of selected organic additives, which are commonly used in shaping of ceramic materials by colloidal methods. Shaping of ceramics requires using different additives which then are burned out during sintering process. For this reason, the knowledge about thermal degradation of organics used, as well as decomposition products, seems to be very important from the application point of view. The analyzed substances were as follows: diammonium hydrocitrate, citric acid, ammonium salt of acrylic polymer, l-ascorbic acid, N,N,N′,N′-tetramethylethylenediamine, and ammonium persulfate. The thermal analysis has been done on the apparatus coupled with mass spectrometer what allowed to observe what types of gasses are released to the atmosphere during heating. The obtained results showed important differences in thermal degradation of organic additives. It was possible to determine at what temperature regions harmful gases like N2O, NO2, or SO2 are released from the organics and which additives can be treated as environmentally friendly.
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TL;DR: In this paper, the authors focused on the characterization of the composites containing nickel aluminate spinel from Al2O3/NiO and Al 2O3-Ni systems.
Abstract: This paper focused on the characterization of the composites containing nickel aluminate spinel from Al2O3/NiO and Al2O3/Ni systems. The composites were prepared by die pressing of powders and subsequent sintering of green bodies in air atmosphere. Composites were characterized by XRD, SEM, EDS and DTA/TG/MS analyses. The physical properties of the composites were measured by Archimedes method. Quantitative description of the composites microstructure was made on the basis of SEM images using computer image analysis. The XRD studies and SEM observations of composites confirmed the presence of two phases Al2O3 and NiAl2O4 in the whole volume of samples from both systems. Spinel phase was evenly distributed throughout the volume of the material. Morphology of NiAl2O4 obtained from both systems was characterized by the presence of voids. The DTA/TG/MS measurements showed the characteristics of organic binder decomposition and type of gases released to the atmosphere during thermal treatment. Moreover, the DTA/TG analysis showed the temperature of spinel-phase formation for both systems. It was found that the spinel-phase NiAl2O4 formation retards the process of densification. Therefore, it can be concluded that densification of samples with spinel phase depends mainly on the volume of spinel phase in composite material and does not depend on the substrates used to prepare spinel phase. The values of the selected properties of Al2O3–Ni- and Al2O3–NiO-based materials confirmed that the physical properties depend on the type of substrates used in the fabrication of composites. The type of powder influences the open porosity of samples. For composites produced using NiO powder, open porosity is lower than for samples formed with nickel powder.
39 citations
Cites background from "Thermal degradation of organic addi..."
...The broader description concerning mass-to-charge ratio m/z for selected substances was described in previous papers [26, 27]....
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Abstract: This study compared the kinetics of biodiesel produced over mesoporous ZSM-5 zeolites (0.3mesoZBio and 0.4mesoZBio) and conventional ZSM-5 zeolites (ZBio). The pyrolysis of each biodiesel was carried out in the presence of nitrogen at different heating rates of 10, 15 and 20 °C min−1. The reaction order, activation energy (EA) and frequency factor (A) were computed using four different models. The models are Arrhenius, Coats–Redfern, Ingraham–Marrier and Differential model. According to the computed average activation energy based on first order, the activation energies of the produced biodiesel are very close. ZBio exhibits the highest EA (86.53 kJ mol−1) compared to 0.3mesoZBio and 0.4mesoZBio (84.92 and 83.26 kJ mol−1, respectively). Therefore, it is tenable to adduce ZBio as the most stable because higher activation energy engenders higher stability.
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References
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TL;DR: In this paper, the thermal decomposition of citric acid, trans-and cis-aconitic acid has been studied using the TG-MS, TG-FTIR and DSC techniques.
Abstract: Thermal decomposition of citric acid, trans- and cis-aconitic acid has been studied using the TG-MS, TG-FTIR and DSC techniques. The measurements were carried out in an argon atmosphere over a temperature range of 293–673 K. The influence of the acid structures and configurational geometry on stability of the transition products and pathways of thermal transformations of the studied compounds studied is discussed.
181 citations
"Thermal degradation of organic addi..." refers background in this paper
...[23] to propose the thermal transformation pattern of the citric acid showing the intermediate products, such as trans-aconitic acid and citraconic anhydride....
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TL;DR: In this article, the authors present examples of applications of differential scanning calorimetry (DSC), modulated temperature differential scanning calculus, dynamic mechanical thermal analysis (DMA), thermal mechanical analysis (TMA), thermogravimeric analysis (TG) and thermoanalytical methods.
Abstract: Thermal analysis is a useful tool for investigating the properties of polymer/clay nanocomposites and mechanisms of improvement of thermal properties. This review work presents examples of applications of differential scanning calorimetry (DSC), modulated temperature differential scanning calorimetry (MT-DSC), dynamic mechanical thermal analysis (DMA), thermal mechanical analysis (TMA), thermogravimeric analysis (TG) and thermoanalytical methods i.e. TG coupled with Fourier transformation infrared spectroscopy (TG-FTIR) and mass spectroscopy (TG-MS) in characterization of nanocomposite materials. Complex behavior of different polymeric matrices upon modification with montmorillonite is briefly discussed.
120 citations
TL;DR: In this article, the authors used agarose as a gelling agent for the gel-casting of highly porous HAp-(α-TCP) (CaP) foams, which exhibited a broad pore size distribution with cells and windows ranging from 250 to 900μm, and from 25 to 250μm.
74 citations
"Thermal degradation of organic addi..." refers background in this paper
...The organic substances can play the role of dispersing agents which stabilize suspensions [7–9], binders which hold particles together [10], plasticizers which give elasticity [11], foaming agents which allow to obtain porous materials [12], monomers [13] together with activators [14] and initiators of polymerization [15] which allow to create polymeric network around non-plastic particles, etc....
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TL;DR: In this article, the authors investigated the thermal stabilities of some antioxidants, in order to evaluate their resistance to thermal oxidation in oils, by heating canola vegetable oil, and to suggest that antioxidants would be more appropriate to increase the resistance of vegetable oils in the thermal degradation process in frying.
Abstract: In this work, through the use of thermal analysis techniques, the thermal stabilities of some antioxidants were investigated, in order to evaluate their resistance to thermal oxidation in oils, by heating canola vegetable oil, and to suggest that antioxidants would be more appropriate to increase the resistance of vegetable oils in the thermal degradation process in frying. The techniques used were: Thermal Gravimetric (TG) and Differential Scanning Calorimetry (DSC) analyses, as well as an allusion to a possible protective action of the vegetable oils, based on the thermal oxidation of canola vegetable oil in the laboratory under constant heating at 180 oC/8 hours for 10 days. The studied antioxidants were: ascorbic acid, sorbic acid, citric acid, sodium erythorbate, BHT (3,5-di-tert-butyl-4-hydroxytoluene), BHA (2, 3-tert-butyl-4-methoxyphenol), TBHQ (tertiary butyl hydroquinone), PG (propyl gallate) - described as antioxidants by ANVISA and the FDA; and also the phytic acid antioxidant and the SAIB (sucrose acetate isobutyrate) additive, which is used in the food industry, in order to test its behavior as an antioxidant in vegetable oil. The following antioxidants: citric acid, sodium erythorbate, BHA, BHT, TBHQ and sorbic acid decompose at temperatures below 180 oC, and therefore, have little protective action in vegetable oils undergoing frying processes. The antioxidants below: phytic acid, ascorbic acid and PG, are the most resistant and begin their decomposition processes at temperatures between 180 and 200 oC. The thermal analytical techniques have also shown that the SAIB antioxidant is the most resistant to oxidative action, and it can be a useful choice in the thermal decomposition prevention of edible oils, improving stability regarding oxidative processes.
64 citations
TL;DR: In this paper, the authors present an overview of the recent trends in near-net-shaping routes, having a deeper look into gelcasting and freeze casting, since both processes are used in the preparation of tailored and custom dense and porous ceramics.
Abstract: Shaping ceramic materials is a research area which has continuing innovation and excellence. Dry processing routes gave way to colloidal techniques enabling the preparation of more complex shapes for a wide and growing field of applications. Both dense and porous ceramics with improved properties can be produced. The development of colloidal processing led to the creation of the near-net-shaping concept, performed through slip casting, gelcasting and freeze casting. Even though these concepts have been used for the last few decades, different trends and combinations of these techniques are refreshing the processing strategies in recent years. New chemistries and concepts continue to emerge. This paper creates an overview of the recent trends in near-net-shaping routes, having a deeper look into gelcasting and freeze casting, since both processes are used in the preparation of tailored and custom dense and porous ceramics.
62 citations
"Thermal degradation of organic addi..." refers methods in this paper
...The appropriate selection of additives is especially important in case of colloidal processing [1], in methods like: slip casting [2], gelcasting [3, 4], tape casting [5], and mechanical foaming [6]....
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