The calculation of the vapor pressures of antioxidants over a range of temperatures using thermogravimetry

Phang, Pauline; Dollimore, D.

doi:10.1016/s0040-6031(00)00651-1

Cited by 22 publications

(8 citation statements)

References 4 publications

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“…The approach described above was adopted by Dollimore et al resulting in a series of publications on the technique by re-defining or modifying the calibration protocol [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47]. However, our original intent was not to measure vapour pressures but to determine the enthalpy of vaporisation (DH vap ) of dyes and UV absorbers in order to screen them for a solid-state dye diffusion process [2,48] since the solubilities in target substrates are governed by the cohesive energy density (d) [49]:…”

Section: Further Developmentsmentioning

confidence: 99%

A fit of the vapours

Price

2015

Thermochimica Acta

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Section: Further Developmentsmentioning

confidence: 99%

A fit of the vapours

Price

2015

Thermochimica Acta

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“…Nowadays, thermogravimetry (TG) has been well established as a common and rapid technique to study the thermal property for volatile chemicals [1], especially their vapour pressure curves and vaporization enthalpies (Δ H vap ). Using such a method, some studies have been carried out for the volatile chemicals: pharmaceuticals [2], UV absorbers [3], antioxidants [4], organometallic compounds [5] and biological agents [6]. In earlier years, TG was used in an isothermal condition, but more recently, an increasing temperature heating programme, which leads to faster data collection and reduces the number of samples required [7,8], has been used in TG.…”

Section: Introductionmentioning

confidence: 99%

Determination of the vapour pressure curves and vaporization enthalpies of hafnium alkoxides using thermogravimetric analysis

2019

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In order to identify a volatile metallo-organic precursor for the deposition of hafnium oxide (HfO2) films for atomic layer deposition (ALD) applications, the evaporative properties of hafnium alkoxides (hafnium isopropoxide, hafnium n-propoxide and hafnium n-butoxide) were investigated using thermogravimetric analysis. These hafnium alkoxide samples were synthesized by the electrochemical method and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance and inductively coupled plasma analysis techniques. The characterization results indicated that the products were 99.997% high-purity hafnium alkoxides and could meet the requirement of purity considering the usage of making HfO2 gate oxide by ALD. Synthesized samples were subjected to a simultaneous thermogravimetric–differential thermal analysis unit at 10 K min−1 in a dry nitrogen atmosphere flowing at 100 ml min−1. Benzoic acid was used to calculate a calibration constant, which could then be inserted into a modified Langmuir equation to calculate vapour pressure curves for hafnium isopropoxide and hafnium n-propoxide. Detailed vapour pressure data for the HfO2 precursor hafnium alkoxides were determined. The vapour pressure curve of hafnium isopropoxide was constructed within the first stage, and calculated to be lnp = 31.157 (±0.200)−13130.57 (±56.50)/T. Hafnium n-propoxide and hafnium n-butoxide were simultaneously undergoing evaporation and decomposition, thus making calculations invalid.

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“…The analysis methods based on thermogravimetry, Langmuir and the Clausius-Clapeyron expression have demonstrated to be accurate for many materials over a narrow temperature range, and they have been used extensively in the determination of many thermodynamic properties of materials with ideal behavior; in the pharmaceutical industry [5][6][7][8][9]; the applications also include the examination of antioxidants [10], dyes [11] and explosives [12] among others ideal thermal, in which none decomposition process occur.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear models of the experimental thermal profile

Espinosa-Fuentes

Pájaro-Payares

Colpas-Castillo

et al. 2015

J Therm Anal Calorim

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This manuscript deals with a mathematical analysis of the functions that should be used in the Clausius-Clapeyron thermodynamic modeling, which is usually modeled as a linear fit; this research emphasizes that the thermal models are nonlinear even taking into account the heat capacity functions as a constant. Specifically, the mathematical analysis of the thermal models proposes what equations should be used depending on the type of enthalpy function. Consequently, the enthalpy functions depend on the model of the heat capacity proposed by Albert Einstein. The magnitude of the errors that would be committed by using linear regressions was also estimated, as is the case for the vast majority of publications in this area. This study also shows how the models behave in a wide temperature range and how they are becoming apparently linear as the temperature range decreases.

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The calculation of the vapor pressures of antioxidants over a range of temperatures using thermogravimetry

Cited by 22 publications

References 4 publications

A fit of the vapours

A fit of the vapours

Determination of the vapour pressure curves and vaporization enthalpies of hafnium alkoxides using thermogravimetric analysis

Nonlinear models of the experimental thermal profile

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