Some variants of the Freeman-Carroll method

Segal, E.; Fãtu, D.

doi:10.1007/bf01909266

Cited by 19 publications

(3 citation statements)

References 6 publications

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“…Furthermore, the decomposition activation energies of the above polymers have been calculated by the Freeman-Carroll differential method [44], which can be expressed by the following equation lg…”

Section: Discussionmentioning

confidence: 99%

Thermo-stability of acrylate based holographic polymer dispersed liquid crystal gratings

Zheng¹,

Yao²,

Zhang³

et al. 2009

J. Phys. D: Appl. Phys.

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The thermo-stability of acrylate based holographic polymer dispersed liquid crystal gratings has been evaluated with regard to their morphology, diffraction efficiency, Bragg angle and electro-optical tunable performance. Our studies indicate that the thermo-stability is closely related to the chemical structure of the monomers in the grating. Usually, a more rigid molecular structure forms a more stable morphology. Another important aspect, the reaction efficiency of the system, shows that a highly efficient photoreaction leads to a dense polymer network and high ene-conversion, thus promoting the phase separation of the liquid crystal and enhancing the thermo-stability. We also find that a higher average functionality of the monomers can improve grating thermo-stability due to denser crosslinked polymers and more complete phase separation.

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Section: Discussionmentioning

confidence: 99%

Thermo-stability of acrylate based holographic polymer dispersed liquid crystal gratings

Zheng¹,

Yao²,

Zhang³

et al. 2009

J. Phys. D: Appl. Phys.

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“…Segal and Fatu proposed a model to predict kinematic parameters from TGA/DTG data for non-isothermal reactions . To use this method, isokinetic conditions must exist during the experiment.…”

Section: Modelingmentioning

confidence: 99%

“…Segal and Fatu proposed a model to predict kinematic parameters from TGA/DTG data for non-isothermal reactions. 16 To use this method, isokinetic conditions must exist during the experiment. According to the DTG curve displayed in Figure 1a, both 320 and 360 °C have the same rate of reaction.…”

Section: Modelingmentioning

confidence: 99%

Detailed Study of Low-Temperature Oxidation of an Alaska Heavy Oil

2012

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In this work, low-temperature oxidation (LTO) of a heavy oil sample from Alaska has been investigated. Six isothermal and one non-isothermal experimental runs were conducted between 100 and 350 °C, where LTO dominates. The combustion data obtained from a thermogravimetric analyzer (TGA) was analyzed, and a comparison has been made between the kinetic parameters (reaction order, rate constant, and activation energy) from a first-order, general reaction rate and Segal and Fatu's approach. The temperature scan of the oxidation process revealed that there were four temperature intervals during which different modes dominated the LTO process. The first temperature interval, ranging from 100 to 150 °C, and the third interval, ranging from 200 to 250 °C, both had overall reactions that were endothermic. However, in the second zone from 150 and 200 °C and the fourth subzone from 250 to 350 °C, exothermic reactions were dominant. The peak LTO rate occurred during the fourth interval, from 250 to 350 °C, and exhibits a decreasing rate versus temperature: the greater the temperature, the lower the reaction rate. The results obtained from the isothermal runs reveal that the reaction rate constant, activation energy, and pre-exponential factor for each temperature (determined from the first-order rate model) are all higher than those measures obtained in the general reaction rate model. The results from the non-isothermal runs showed that the values of the reaction rate constant, activation energy, and pre-exponential factor obtained from the approach by Segal and Fatu are similar to those calculated from the general reaction rate model. This was particularly true for the LTO peak temperature. The analysis of the results yields the mean activation energy for the LTO peak equal to 1130.2 cal/mol for isothermal experiments.

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Analysis of dynamic kinetic data from solid-state reactions

Tang

Chaudhri

1980

Journal of Thermal Analysis

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Some variants of the Freeman-Carroll method

Cited by 19 publications

References 6 publications

Thermo-stability of acrylate based holographic polymer dispersed liquid crystal gratings

Thermo-stability of acrylate based holographic polymer dispersed liquid crystal gratings

Detailed Study of Low-Temperature Oxidation of an Alaska Heavy Oil

Analysis of dynamic kinetic data from solid-state reactions

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