A systematic approach for thermal stability predictions of chemicals and their risk assessment: Pattern recognition and compounds classification based on thermal decomposition curves

2017 ◽  
Vol 110 ◽  
pp. 43-52 ◽  
Author(s):  
L. Mage ◽  
N. Baati ◽  
A. Nanchen ◽  
F. Stoessel ◽  
Th. Meyer
Keyword(s):  
Risk Assessment ◽  
Thermal Stability ◽  
Thermal Decomposition ◽  
Pattern Recognition ◽  
Systematic Approach

Non-Isothermal Decomposition Kinetic of Polypropylene/Hydrotalcite Composite

2019 ◽  
Vol 19 (11) ◽  
pp. 7493-7501 ◽  
Author(s):  
Sheng Xu ◽  
Min Zhang ◽  
Siyu Li ◽  
Moyu Yi ◽  
Shigen Shen ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Nitrogen Atmosphere ◽  
Heating Rates ◽  
Decomposition Reactions ◽  
Kinetic And Thermodynamic Parameters ◽  
Málek Method ◽  
Boundary Reaction ◽  
Phase Boundary Reaction ◽  
Thermal Stability Of

P3O5-10 pillared Mg/Al hydrotalcite (HTs) as a functional fire-retarding filler was successfully prepared by impregnation-reconstruction, where the HTs was used to prepare polypropylene (PP) and HTs composite (PP/HTs). Thermal decomposition was crucial for correctly identifying the thermal behavior for the PP/HTs, and studied using thermogravimetry (TG) at different heating rates. Based on single TG curves and Málek method, as well as 41 mechanism functions, the thermal decompositions of the PP/HTs composite and PP in nitrogen atmosphere were studied under non-isothermal conditions. The mechanism functions of the thermal decomposition reactions for the PP/HTs composite and PP were separately “chemical reaction F3” and “phase boundary reaction R2,” which were also in good agreement with corresponding experimental data. It was found that the addition of the HTs increased the apparent activation energy Ea of the PP/HTs comparing to the PP, which improved the thermal stability of the polypropylene. A difference in the set of kinetic and thermodynamic parameters was also observed between the PP/HTs and PP, particularly with respect to lower ΔS≠ value assigned to higher thermal stability of the PP/HTs composite.

scholarly journals The influence of the nature and textural properties of different supports on the thermal behavior of Keggin type heteropolyacids

2006 ◽  
Vol 71 (3) ◽  
pp. 235-249 ◽  
Author(s):  
Alexandru Popa ◽  
Viorel Sasca ◽  
Mircea Stefanescu ◽  
Erne Kis ◽  
Radmila Marinkovic-Neducin
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Thermal Behavior ◽  
Solid Phase ◽  
Textural Properties ◽  
Nitrogen Adsorption ◽  
Active Phase ◽  
Support Surface ◽  
Sem Images ◽  
The Stability

In order to obtain highly dispersed heteropolyacids (HPAs) species, H3PMo12O40 and H4PVMo11O40 were supported on various supports: silica (Aerosil - Degussa and Romsil types) and TiO2. The structure and thermal decomposition of supported and unsupported HPAs were followed by different techniques (TGA-DTA, FTIR, XRD, low temperature nitrogen adsorption, scanning electron microscopy). All the supported HPAs were prepared by impregnation using the incipient wetness technique with a 1:1 mixture of water-ethanol. Samples were prepared with different concentrations to examine the effect of loading on the thermal behavior of the supported acid catalysts. The thermal stability was evaluated with reference to the bulk solid acids and mechanical mixtures. After deposition on silica types supports, an important decrease in thermal stability was observed on the Romsil types and a small decrease on the Aerosil type. The stability of the heteropolyacids supported on titania increased due to an anion-support interaction, as the thermal decomposition proceeded in two steps. The structure of the HPAs was not totally destroyed at 450 ?C as some IR bands were still preserved. A relatively uniform distribution of HPAs on the support surface was observed for all compositions of the active phase. No separate crystallites of solid phase HPAs were found in the SEM images.

scholarly journals STUDY OF THERMAL DECOMPOSITION PRODUCTS OF NITROGEN-PHOSPHORUS-POTASSIUM FERTILIZERS BASED ON AMMONIUM NITRATE BY X-RAY DIFFRACTUON

2017 ◽  
Vol 61 (1) ◽  
pp. 72
Author(s):  
Konstantin G. Gorbovskiy ◽  
Alena S. Ryzhova ◽  
Andrey M. Norov ◽  
Denis A. Pagaleshkin ◽  
Valentina N. Kalinina ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Decomposition ◽  
Phosphoric Acid ◽  
Ammonium Nitrate ◽  
Confined Space ◽  
Decomposition Products ◽  
X Ray ◽  
Thermal Decomposition Products ◽  
Nitrogen Phosphorus ◽  
Thermal Stability Of

Complex mineral ammonium nitrate-based fertilizers are complex multicomponent salt systems possessing low thermal stability and prone to self-sustaining decomposition. This leads to the need to increase the requirements for fire and explosion safety in their manufacture, storage and transportation, caused by the fact that ammonium nitrate is a solid oxidant able to support a combustion, and its heating in confined space can lead to detonation. Components that make up such fertilizers can both reduce (phosphates and ammonium sulfate) and accelerate (chlorine compounds) decomposition of ammonium nitrate. Thus, the thermal stability of fertilizers based on ammonium nitrate largely depends on the ratio of the components that make up its composition or formed as a result of the chemical reaction. The simplest way to reduce the content of ammonium nitrate and increase the thermal stability of fertilizer without changing the content of essential nutrients is to increase the degree of phosphoric acid ammoniation. In this paper, the phase composition change of grade 22:11:11 nitrogen-phosphorus-potassium fertilizer obtained with different ammoniation degree in the process of thermal decomposition was studied by X-ray phase analysis. To obtain this fertilizer, wet-process phosphoric acid obtained sulfuric acid attack of the Khibin apatite concentrate by a hemihydrate method is used. It is shown that an increase in the ammoniation degree has a significant effect on the exothermic decomposition of ammonium nitrate and the amount of material that is released into the gas phase. The phases formed at each stage of the decomposition are determined.Forcitation:Gorbovskiy K.G., Ryzhova A.S., Norov A.M., Pagaleshkin D.A., Kalinina V.N., Mikhaylichenko A.I. Study of thermal decomposition products of nitrogen-phosphorus-potassium fertilizers based on ammonium nitrate by X-ray diffractuon. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 1. P. 72-77

scholarly journals Obtaining and Characterization of a Polyurethane Carrier Used for Eugenol as a Possible Remedy in Oral Therapies

2018 ◽  
Vol 55 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Zoran Popa ◽  
Laura Cristina Rusu ◽  
Razvan Susan ◽  
Iulia Pinzaru ◽  
Elena Ardelean ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Thermal Stability ◽  
Thermal Decomposition ◽  
Drug Delivery System ◽  
Transmembrane Transport ◽  
Vein Wall ◽  
Good Thermal Stability ◽  
Toxicity Effect ◽  
Low Solubility

The cloves are antiseptic, antiparasitic, antibacterial, antifungal, antiviral, anesthetic, analgesic, anti-inflammatory, tonic, carminative, anti-ulcer, antithrombotic, antioxidant and anti-cancerous. They contain eugenol, tannins and flavonoids that also help to strengthen the vein wall. This paper presents the obtaining and the characterization of a polyurethane drug delivery system which can be used for the transmembrane transport of eugenol in oral therapies. The products were analyzed by pH and solubility measurements, thermal decomposition and zetasizer tests and they were applied on mice skin to evaluate their harmfulness. The results suggest that were obtained neutral pH structures with low solubility and a good thermal stability, with sizes between 241 and 289 nm and no toxicity effect was found in the case of studied samples.

scholarly journals Thermal stability and thermal decomposition of sucralose

2018 ◽  
Vol 39 (4) ◽  
pp. 21
Author(s):  
Gilbert Bannach ◽  
Rafael R. Almeida ◽  
Luis G. Lacerda ◽  
Egon Schnitzler ◽  
Massao Ionashiro
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Differential Thermal Analysis ◽  
Infrared Spectroscopy ◽  
Scanning Calorimetry ◽  
Thermoanalytical Techniques ◽  
Thermal Stability Of

Several papers have been described on the thermal stability of the sweetener, C12H19Cl3O8 (Sucralose). Nevertheless no study using thermoanalytical techniques was found in the literature. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC) and infrared spectroscopy, have been used to study the thermal stability and thermal decomposition of sweetener.

scholarly journals Study on Thermal Decomposition Behaviors of Terpolymers of Carbon Dioxide, Propylene Oxide, and Cyclohexene Oxide

2018 ◽  
Vol 19 (12) ◽  
pp. 3723 ◽  
Author(s):  
Shaoyun Chen ◽  
Min Xiao ◽  
Luyi Sun ◽  
Yuezhong Meng
Keyword(s):  
Carbon Dioxide ◽  
Thermal Stability ◽  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Propylene Carbonate ◽  
Cyclohexene Oxide ◽  
Block Polymers ◽  
Rate Method ◽  
Poly Propylene ◽  
Thermal Stability Of

The terpolymerization of carbon dioxide (CO2), propylene oxide (PO), and cyclohexene oxide (CHO) were performed by both random polymerization and block polymerization to synthesize the random poly (propylene cyclohexene carbonate) (PPCHC), di-block polymers of poly (propylene carbonate–cyclohexyl carbonate) (PPC-PCHC), and tri-block polymers of poly (cyclohexyl carbonate–propylene carbonate–cyclohexyl carbonate) (PCHC-PPC-PCHC). The kinetics of the thermal degradation of the terpolymers was investigated by the multiple heating rate method (Kissinger-Akahira-Sunose (KAS) method), the single heating rate method (Coats-Redfern method), and the Isoconversional kinetic analysis method proposed by Vyazovkin with the data from thermogravimetric analysis under dynamic conditions. The values of ln k vs. T−1 for the thermal decomposition of four polymers demonstrate the thermal stability of PPC and PPC-PCHC are poorer than PPCHC and PCHC-PPC-PCHC. In addition, for PPCHC and PCHC-PPC-PCHC, there is an intersection between the two rate constant lines, which means that, for thermal stability of PPCHC, it is more stable than PCHC-PPC-PCHC at the temperature less than 309 °C and less stable when the decomposed temperature is more than 309 °C. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric analysis/infrared spectrometry (TG/FTIR) techniques were applied to investigate the thermal degradation behavior of the polymers. The results showed that unzipping was the main degradation mechanism of all polymers so the final pyrolysates were cyclic propylene carbonate and cyclic cyclohexene carbonate. For the block copolymers, the main chain scission reaction first occurs at PC-PC linkages initiating an unzipping reaction of PPC chain and then, at CHC–CHC linkages, initiating an unzipping reaction of the PCHC chain. That is why the T−5% of di-block and tri-block polymers were not much higher than that of PPC while two maximum decomposition temperatures were observed for both the block copolymer and the second one were much higher than that of PPC. For PPCHC, the random arranged bulky cyclohexane groups in the polymer chain can effectively suppress the backbiting process and retard the unzipping reaction. Thus, it exhibited much higher T−5% than that of PPC and block copolymers.

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