Magnetically Stimulable Graphene Oxide/Polypropylene Nanocomposites

Core-shell magnetic air-stable nanoparticles haveattractedincreasing interest in recent years. Attaining a satisfactory distributionof magnetic nanoparticles (MNPs) in polymeric matrices is difficultdue to magnetically induced aggregation, and supporting the MNPs ona nonmagnetic core-shell is a well-established strategy. Inorder to obtain magnetically active polypropylene (PP) nanocompositesby melt mixing, the thermal reduction of graphene oxides (TrGO) attwo different temperatures (600 and 1000 degrees C) was carried out,and, subsequently, metallic nanoparticles (Co or Ni) were dispersedon them. The XRD patterns of the nanoparticles show the characteristicpeaks of the graphene, Co, and Ni nanoparticles, where the estimatedsizes of Ni and Co were 3.59 and 4.25 nm, respectively. The Ramanspectroscopy presents typical D and G bands of graphene materialsas well as the corresponding peaks of Ni and Co nanoparticles. Elementaland surface area studies show that the carbon content and surfacearea increase with thermal reduction, as expected, following a reductionin the surface area by the support of MNPs. Atomic absorption spectroscopydemonstrates about 9-12 wt % metallic nanoparticles supportedon the TrGO surface, showing that the reduction of GO at two differenttemperatures has no significant effect on the support of metallicnanoparticles. Fourier transform infrared (FT-IR) spectroscopy showsthat the addition of a filler does not alter the chemical structureof the polymer. Scanning electron microscopy of the fracture interfaceof the samples demonstrates consistent dispersion of the filler inthe polymer. The TGA analysis shows that, with the incorporation ofthe filler, the initial (T (onset)) and maximum(T (max)) degradation temperatures of thePP nanocomposites increase up to 34 and 19 degrees C, respectively.The DSC results present an improvement in the crystallization temperatureand percent crystallinity. The filler addition slightly enhances theelastic modulus of the nanocomposites. The results of the water contactangle confirm that the prepared nanocomposites are hydrophilic. Importantly,the diamagnetic matrix is transformed into a ferromagnetic one withthe addition of the magnetic filler.