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Porous magnetite (Fe3O4) and hematite (α-Fe2O3) nanoparticles were prepared via the sol-gel auto-combustion method. The gels were prepared by reacting ferric nitrates (as oxidants) with starch (as fuel) at an elevated temperature of 200 °C. Different ratios (Φ) of ferric nitrates to starch were used for the synthesis (Φ = fuel/oxidant). The synthesized iron oxides were characterized by Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, X-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmet-Teller (BET) and vibrating sample magnetometer (VSM) analysis techniques. The crystal structure, morphology, and specific surface area of the iron oxide nanoparticles (Fe3O4 and α-Fe2O3) were found to be dependent on the starch content. The FT-IR, XRD and VSM analysis of the iron oxides for Φ = 0.3 and 0.7 confirmed the formation of the α-Fe2O3 core, whereas at Φ = 1, 1.7, and 2 showed that Fe3O4 cores were formed with the highest saturation magnetization of 60.36 emu/g at Φ = 1. The morphology of the Fe3O4 nanoparticles exhibited a quasi-spherical shape, while α-Fe2O3 nanoparticles appeared polygonal and formed clusters. The highest specific surface area was found to be 48 m² g-1 for Φ = 1.7 owing to the rapid thermal decomposition process. Type II and type III isotherms indicated mesoporous structures. [ABSTRACT FROM AUTHOR]

Zinc oxide/sodium cellulose composite with different ZnO loadings was prepared for the first time. The crystal structures of cellulose, sodium cellulose, and ZnO/sodium cellulose composite were characterized by FT-IR, XRD, XPS, SEM, and EDX. ZnO/sodium cellulose showed a similar XRD pattern to that of cellulose II. The XPS spectrum emphasized the presence of Zn2+ and Na+ ions in the prepared composite. Additionally, the SEM analysis showed the growth of ZnO crystals on the sodium cellulose surface. UV-Vis spectrometry of the ZnO/sodium cellulose spectrum showed a distinguished absorption band at 360 nm that was attributed to the presence of ZnO particles on the cellulosic fibers. As a result, the composite fibers swelled, and their diameter increased from 15 μm to 30 μm. Furthermore, ZnO/sodium cellulose exhibited lower air and water vapor permeability than cellulose and sodium cellulose and can be perfectly utilized as food packing film to increase the shelf life of preserved foods. [ABSTRACT FROM AUTHOR]

In order to investigate the interaction of graphene oxide (GO) with different cellulose polymorphs (I and II), we synthesized cellulose (I and II)/GO composites using the sonication method. Interestingly, no new peaks were observed in the FT-IR pattern of the cellulose (I and II)/GO composites, indicating that no chemical reactions took place between GO and cellulose. The X-ray diffraction patterns of cellulose I and II/GO composites were slightly different than those observed for cellulose I and II, indicating that some physical interactions occurred between the GO and cellulose. Unexpectedly the d-spacing values and the diffraction plane at the high-angle side were most likely expanded in cellulose I rather than in cellulose II by adding GO, confirming the highest reactivity of GO toward cellulose I rather than cellulose II. Furthermore, SEM images showed that the conformal coating of GO on cellulose I was larger than that on cellulose II due to the strong adhesion between the GO and cellulose I. Cellulose/GO showed antimicrobial properties, and GO was found to be promising for textile antimicrobial finishing. [ABSTRACT FROM AUTHOR]