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چکیده
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Poly(vinyl alcohol) (PVA) containing Ag-modified X-zeolite (PVA/X-zeolite) nanocomposite was successfully fabricated using solution casting technique. Morphology, structural and thermal properties of the pure PVA and its nanocomposite were characterized by FEscanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX), X-ray diffraction, and differential scanning calorimetry (DSC), respectively. Results from DSC traces showed that the X-zeolite acts as efficient nucleating agent toward PVA crystallization. Photographs of FE-SEM demonstrate the nanosize and homogenous dispersion of the X-zeolite in PVA matrix. Moreover, EDX analysis confirmed the presence of constituent elements of the X-zeolite in the nanocomposite as well. Thermal degradation of PVA and PVA/X-zeolite nanocomposite was addressed in details by thermogravimetry analysis under non-isothermal conditions. Similar to pure PVA, the PVA/X-zeolite nanocomposite thermally degraded in two steps ranged from 400 to 690 K and 700 to 780 K, respectively. Values of the apparent activation energies were estimated using Friedman’s isoconversional method. A strong dependence of the Ea on conversion (a) was observed. To confirm the anticipated reaction models, differential master plot analysis was applied to the experimental data. Results showed that the degradation of PVA and its nanocomposite could be described by the reactionorder (A type) kinetic model.
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