Mateusz Fijalkowski

Antioxidant Effect of Hydroxylated Diamond Nanoparticles Measured in Soybean Oil

We investigated the antioxidant properties of detonation nanodiamond modified by Fentons reagent. Diamond nanoparticles functionalized with hydroxyl groups were examined in soybean oil; the aim of this study was to determine their antioxidant properties by examining the effect on the lipid peroxidation process. In order to form the hydroxyl groups on the surface of the detonation diamond nanoparticles, we utilized the Fenton reaction. This reaction consisted of the oxidation of the surfaces of the nanodiamonds by the reaction of Fe2+ with hydrogen peroxide (H2O2), which is a precursor of the hydroxyl radical. The oxidation reaction of nanodiamonds via Fentons reagent is twofold, in addition to surface oxidation it is also purified from different carbon varieties. We traced the impact of the modified nanodiamonds on the oxidation process of soybean oil. In order to hasten the process of lipid peroxidation, the soybean oil was exposure to ultraviolet (UV) light with a wavelength of 250 nm. Analysis was performed before and after 3, 6, 9, 24, 48, and 72 hours of exposure to UV light. Comparing the results of pure oil and oil with the addition of functionalized powder, we noted a significant impact of the modified nanodiamond compared to nonmodified nanodiamond on the process of counteracting the rancidity of the oil. This observation was confirmed by the peroxide value, anisidine value, Totox index, and Kreis test.

Rice Husks - Structure, Composition and Possibility of Use them at Surface Treatment

Rice husks (RH) are characterized by a high content of silicon dioxide up to 23 wt. %. Silica in the form of nanoparticles creates surface layers formed in various plant parts which ensure protective properties and mechanical stability. These nanoparticles with a dimension in the range of tens of nanometers, are formed during biochemical processes and photosynthesis. Individual nanoparticles are interconnected between themselves and between layers with organic phase via cellulose fibres. Accompanying ions mainly potassium, calcium, sodium, magnesium and aluminium extremely important for plant growth have also been identified in rice husks. In this research paper we investigated mechanical properties of composite epoxy resin material, which was composed of ChS Epoxy 520 filled with silica obtained from rice husks. Nanoparticles of silicon dioxide with the size in dozen of nanometers were prepared by calcination of raw plant parts. We found that the 0.1 phr of filling (0.01 g of filler + 10 g of epoxy) demonstrated a significant increase of wear resistance and decrease of coefficient of friction. An excellent adhesion between epoxy resin and silica nanoparticles was also observed. The silicon dioxide in epoxy resin plays the role of the hard phase, which transfers part of the load and protects the surface of polymer against wear. The presence of this filler does not change the mechanical properties of the original resin.