تحضري ودراسة خصائص مركبات المواد ذات أساس بنتونيت/بوليمر اكريليك
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Date
2024-03-07
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Abstract
The thesis addresses the topic of “Elaboration and study of the properties of
bentonite/acrylic polymer based material composites” based on tripropylene glycol
diacrylate (TPGDA) and bentonite.
In this research, we conducted three studies. The interest was initially in studying the
kinetics and mechanisms of phase transformations of local raw bentonite from Maghnia
(Algeria), after the calcination process at different temperatures, and as a result, the
physicochemical properties were studied using (XRD) and (FTIR) devices. (SEM) of the
calcined samples, then the material was examined by differential thermal analysis (DTA)
at different heating rates (10- 50°C/min). Through the examination, we experimentally
calculated the activation energy for the dehydroxylation reaction stage. With the help of
the theoretical aspect, when it was treated in two different ways, the first by holding the
temperature constant, and the second by changing it at different heating speeds, and after
the calcination process at 200 and 700 °C for the bentonite, the X-ray diffraction data
showed a decrease in the value of the separation distance (d001), which expresses the
montmorillonite phase, from 12.72. Å at room temperature to about 11.98 Å and 9.93 Å
and then disappearing after calcination at 800°C. The values of the average activation
energies determined by the Kissinger method are 221.046 kJ/mol and the Ligero method
are 233.076 kJ/mol.
As for the second study, the cross-linked nanocomposite was prepared from tripropylene
glycol diacrylate (TPGDA) and montmorillonite (pure local bentonite), where cation
exchange of montmorillonite was performed using potassium chloride (KCl), sodium
chloride (NaCl), and lithium chloride (LiCl). As a source of K+, Na+, and Li+ cations,
respectively, the physicochemical properties of the prepared samples were then studied
using (XRD), (FTIR), (SEM), and (TGA) devices, which demonstrated the success of
intercalation of TPGDA monomers and their crosslinking within the montmorillonite layers
to obtain On the Cross-linked(TPGDA)/MMtMag-M+ nanocomposite, based on the DTG
curve, we calculated the activation energy and kinetic parameters in the TPGDA
decomposition stage for each sample using the Coats–Redfern model.
As for the third study, we studied the electrical insulation properties of the
nanocomposite Cross-linked (TPGDA)/MMtWy-Cs+ over a frequency range from 12 to 200
MHz and in a temperature range from 293 to 373 K, where we relied on Wyming
montmorillonite as a reinforcement material for this compound. The results showed that
adding TPGDA to MMtWy-Cs+ resulted in improved AC conductivity, dielectric constant,
and angular loss (tanδ) compared to pure MMtWy.
Description
Keywords
bentonite, Differential thermal analysis, Kinetic parameters, Activation energy, Dehydroxylation. nanocomposites, dielectric properties.