Magnetism being one of the oldest scientific disciplines has been continuously studied since 6 th century BC, which still offers scientific innovations today in realm of nanomagnetism. Iron oxide nanomaterials have been growing excessive importance because of their magnetic characteristics and wide applications. Iron oxides magnetic nanoparticles with appropriate surface chemistry are prepared either by wet chemical method such as colloid chemical or sol-gel methods or by dry processes such as vapour deposition techniques. This review summarizes comparative and brief study of the methods for the preparation of iron oxide magnetic nanoparticles with a control over the size, morphology and the magnetic properties. Applications of microwave irradiation for magnetic particle synthesis are also addressed.

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In this study, castor oil-based polyurethanes-organoclay (COPUsCloisite 30B) nanocomposites are synthesized by mixing polypropylene glycol polyol and dehydrated castor oil (15 %), enforced with C30B nanofillers, at different weight percentages. The physico-chemical behaviors were evaluated by Fourier transform infrared spectroscopy, Fourier scanning electron microscopy, scanning electron microscopy and X-ray diffraction. Thermal stability was found improved up to *30°C in the sample with 5 wt% of C30B. Tensile properties depicted an improvement of *240 % in tensile strength and decrease of *30 % in elongation with 5 wt% organoclay, respectively. Improved physico-chemical properties of COPUs-C30B signify the usage of COPUs-C30B in the industrial and commercial applications, i.e. coatings, adhesives and automotive applications.

Polyurethanes (PUs) are high performance materials, with vast industrial and engineering applications. In this research, effects of Multiwalled Carbon Nanotubes (MWCNTs) on physicochemical properties of Castor Oil based Polyurethanes (COPUs) were studied. MWCNTs were added in different weight percentages (0% to 1% wt) in a castor oil based polyurethane (COPUs-MWCNTs) nanocomposites. The composition, structure, and morphology of polyurethanes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), and element detection by energy dispersive spectroscopy (EDX) analysis, respectively. Thermal stability was studied by thermogravimetric analysis (TGA). Barrier properties and surface area studies were investigated by nitrogen permeability machine and BET technique. Mechanical properties were calculated by tensile universal testing machine. Results showed well dispersed MWCNTs in polyurethane matrix at different weight percentages. The best results were obtained with 0.3 wt% of MWCNTs in the composite. Surface area studies revealed presence of very few pores which is in a good agreement with barrier permeability, reduced up to ~68% in 1 wt% and ~70% in 0.5 wt% of MWCNTs in polymer matrix, with respect to pure COPUs samples.

The physicochemical properties of an innovative and environmentally friendly composite material based on sugar palm fiber (SPF) and thermoplastic polyurethane (TPU) were examined. The base material with short fibers was extruded and hot pressed to produce the TPU-SPF composites with different synthetic parameters. Operating parameters including temperature for extrusion (170 to 190 °C), rotational velocity (30 to 50 rpm), and fiber particle sizes (160, 250, and 425 µm) were investigated. The aims were to optimize rotational velocity, temperature, and fiber size of the TPU-SPF composites. Firstly, the influence of rotation of velocity and temperature on the tensile properties was investigated. Secondly, effects of different fiber sizes on tensile, flexural properties, and impact strength as per ASTM standards were tested. The morphological, thermal, and physicochemical properties of the synthesized TPU-SPF composites were ascertained with Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The optimal results were observed with a temperature of 190°C and a rotational velocity of 40 rpm. Meanwhile, the strength and modulus for tensile and flexural were best for fiber size 250 µm. Moreover, the impact strength reached a peaking trend at 250 µm fiber size.

In this study, the physico-chemical properties of high performance polyurethane synthesized from poly propylene glycol (PPG) in comparison with a combination of PPG and castor oil, is studied using the in-situ polymerization technique. The variations in properties of both types of polyurethanes are evaluated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and the thermogravimetric analysis (TGA) technique. Tensile strength properties were investigated by film tensile testing equipment. The results indicated the presence of large -CH stretching in the castor oil mixed polyurethane with a larger oxidative thermal stability over pure PPG polyurethanes. The tensile properties were found to be almost comparable in pure and mixed polymers, signifying the usage of mixed polymers in the future to overcome the environmental and economic crisis in polyurethane synthesis.

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