urea

The paper deals with the results of the study on the purification process of used mineral and semi-synthetic motor oils in the presence of crystalline urea. The effect of the process main factors (the amount of the main reagent, time, and temperature) on the performance indicators of purified motor oils was studied. Used mineral and semi-synthetic motor oils for gasoline and diesel engines were purified under the established optimal conditions.

The possibility and effectiveness of using a natural sorbent – peat from the Vereshchytsia-Yanivske deposit for treating agricultural wastewater with a high urea content – has been studied. The humidity and moisture content of the upland and lowland types of peat from this peatland were determined. Comparing these indicators made it possible to establish that the lowland peat has a significantly higher humidity and moisture content. The adsorption capacities of wet and dried types of peat for urea were studied and compared.

Melamine formaldehyde oligomers with peroxy groups (MFOP) have been synthesized based on melamine or urea and melamine in the presence of tert-butyl peroxymethanol or tert-butyl hydroperoxide. Zinc oxide was used as a catalyst. The effect of peroxide nature, ratio of the starting components and process time on the characteristics and yield of MFOP has been studied. The structure of the synthesized MFOP was confirmed by IR- and PMR-spectroscopy. The chemistry of the cross-linked structures formation was studied.

The possibility of synthesis in the presence of tert-butyl peroxymethanol (TBPM) or tert-butyl hydroperoxide (TBHP) of urea-formaldehyde oligomers with peroxide groups (UFOP) has been considered. Zinc oxide was used as the reaction catalyst. The effect of the initial components ratio, the reaction temperature and the process time on the characteristics and yield of the obtained oligomers was studied. Methods for obtaining UFOP using a mixture of TBPM and TBHP as a component are proposed. The structure of the synthesized UFOP was confirmed by IR- and NMR-spectroscopic studies.

Hessian cloth (jute fabrics) samples were soaked in the alcoholic shellac solution and dried at 333 K for 4 hours. Six layers of shellac treated hessian cloth were heat pressed (373 K for 10 min at 5 MT pressure) to fabricate biocomposite and then its mechanical properties were evaluated. To improve the mechanical properties of the biocomposite, a series of formulations was prepared using varying percentages of urea (0.25 to 30 %) with shellac in methanol; then the composite was fabricated using same parameters.