| Summary: | Ferrites are important nanomagnetic materials in chemical industry due to their high applicability in pharmaceutical and electronic devices fabrication. Amongst, manganese and zinc modified ferrite (Mn/Zn ferrite) nanocomposites have attracted intensive interest of researchers because of the relatively high magnetic properties. However, the magnetic properties of the Mn/Zn ferrite materials reduce significantly due to agglomeration especially in aqueous solution. In this research, an attempt was carried out to synthesize polymer coated Mn/Zn ferrite via chemical coprecipitation in order to prevent agglomeration among the nanoparticles. A series of Mn1-xZnxFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) were prepared at 75 oC and calcined at different temperatures (500, 600, 700 °C). X-ray diffraction (XRD) result indicated all the prepared Mn1-xZnxFe2O4 crystallized in spinel cubic structure with crystallite size ranging 4.58 - 11.01 nm. Besides, the increase of Zn amount in the ferrite structure resulted in reduction of both degree of crystallinity and crystallite size. Among the synthesized materials, Mn0.8Zn0.2Fe2O4 had the highest magnetic properties. Two types of polymers: polyethylene glycol (PEG) and polyvinyl alcohol (PVA) were used to coat Mn1-xZnxFe2O4. The spinel structure remained intact after the polymer coating. The presence of polymer on the surface of Mn1-xZnxFe2O4 ferrite was confirmed by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Reduction in the agglomeration was observed in the polymer coated Mn/Zn ferrites as evidenced by the field emission scanning electron microscopy (FESEM) analysis. Different precipitation temperatures (25 - 100 oC) were applied to prepare 10 wt% PEG coated Mn0.8Zn0.2Fe2O4. The XRD and FESEM results showed that both the degree of crystallinity and particle size of the materials increased with increasing of the precipitation temperature. The synthesis temperature of 75oC appeared to be the optimum temperature to produce PEG coated Mn0.8 Zn0.2Fe2O4 with the highest magnetic properties. The thermal stability of Mn0.8 Zn0.2Fe2O4 increased remarkably after coating onto 10 wt% PEG and 10 wt% PVA. Besides, it was observed that the magnetic properties of the materials increased with increasing of polymer concentration. It has been demonstrated that the magnetic properties of Mn0.8Zn0.2Fe2O4 (1.92 emu/g) increased more than 10 time after the polymer coating, where 10 wt% PVA coated Mn0.8Zn0.2Fe2O4 and 10 wt% PEG coated Mn0.8Zn0.2Fe2O4 recorded 28.99 and 20.67 emu/g, respectively. This research has shown that the magnetic property of Mn/Zn ferrite could be enhanced remarkably via polymer coating using PEG and PVA, leading to its increased magnetic susceptibility, in the medical and pharmaceutical applications.
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