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Rheological, Microstructural And Thermal Properties Of Magnetic Poly(Ethylene Oxide)/Iron Oxide Nanocomposite Hydrogels Synthesized Using One-Step Gamma-Irradiation Method

Magnetic polymer gels are a new promising class of nanocomposite gels with numerous potential application as effective absorbents of toxic ions in water, in soft actuators such as artificial muscles, in tissue engineering, drug delivery, hyperthermia applications etc. The aim of this work was to explore the ability of γ-irradiation technique for a one-step synthesis of magnetic hydrogels. Magnetic PEO/iron oxide nanocomposite hydrogels were successfully synthesized using one-step γ- irradiation method starting from poly(ethylene oxide) (PEO) and iron(III) suspensions followed by simultaneous crosslinking of PEO chains and reduction of Fe(III) precursor. γ-irradiation dose and concentrations of Fe3+, 2-propanol and PEO in the initial suspensions were varied and optimized. With 2-propanol and at high doses magnetic hydrogels with embedded magnetite nanoparticles were obtained, as confirmed by XRD, SEM and Mössbauer spectroscopy. The quantitative determination of γ-irradiation generated Fe2+ was performed using the 1, 10- phenanthroline method. DSC and rheological measurements confirmed the formation of well- structured network. The thermal and rheological properties of the gels depended on the dose, PEO concentration and amount of nanoparticles synthesized inside gels (initial Fe3+ content). Both enthalpies and temperatures of melting and crystallization of gels decrease with the dose and the amount of formed magnetic NPs. More amorphous and stronger gels were formed at higher dose and higher nanoparticle content. The properties of the synthesized gels were determined by the presence of magnetic iron oxide nanoparticles, which acted as reinforcing agents and additional crosslinkers of the PEO chains thus facilitating one-step gel formation.

magnetic hydrogel ; gamma-irradiation ; poly(ethylene oxide) ; magnetite ; rheological properties ; thermal properties ; Fe Mössbauer spectrometry ; XRD ; SEM ; Fe(II) determination

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