RESUMEN
Raw vegetable oil from Crambe abyssinica was subjected to oxidative treatment to enhance its viscosity. The oxidation processes were carried out in the presence of N-hydroxyphthalimide with or without supercritical CO2 as a solvent. Four spectroscopic techniques (Raman, UV-VIS, FT-IR, NMR) were applied to assess the chemical changes taking place during the oxidation. Raman and NMR spectroscopy proved best in the assessment of the chemical transformations leading to increased viscosity of the modified vegetable oil.
Asunto(s)
Crambe (Planta)/química , Aceites de Plantas/química , Verduras/química , Ácidos Grasos/análisis , Oxidación-Reducción , Espectroscopía de Protones por Resonancia Magnética , Espectroscopía Infrarroja por Transformada de Fourier , Espectrometría Raman , Triglicéridos/químicaRESUMEN
Lubricants that are based on renewable raw materials have drawn increased attention in various applications, especially those related to the food industry. Due to the high requirements of environmental protection, there is a need to develop biodegradable base oils that are environmentally friendly and do not contain harmful components. The objective of the research was to obtain a base oil with a certain viscosity and certain desired lubricating properties. Base oils were obtained from Crambe abyssinica oil by means of blending with synthetic oil and oxidation. The oxidation processes were carried out in the presence of N-hydroxyphthalimide with or without CO2 as a solvent. As a final result of this study, oil bases meeting the viscosity requirements and showing suitable lubricating properties were obtained. The Raman spectra of the obtained oils were evaluated.
Asunto(s)
Lubricantes/química , Aceites de Plantas/química , Verduras/química , Dióxido de Carbono/química , Catálisis , Lubricantes/análisis , Estructura Molecular , Oxidación-Reducción , Oxígeno/química , Aceites de Plantas/análisis , Reología , Espectrometría Raman , Temperatura , ViscosidadRESUMEN
In this study the attempts to improve mechanical properties of highly-porous titanium dioxide scaffolds produced by polymer sponge replication method were investigated. Particularly the effect of two-step sintering at different temperatures on microstructure and mechanical properties (compression test) of the scaffolds were analysed. To this end microcomputed tomography and scanning electron microscopy were used as analytical methods. Our experiments showed that the most appropriate conditions of manufacturing were when the scaffolds were heat-treated at 1500 °C for 1 h followed by sintering at 1200 °C for 20 h. Such scaffolds exhibited the highest compressive strength which was correlated with the highest linear density and the lowest size of grains. Moreover, grain size distribution was narrower with predominating fraction of fine grains 10-20 µm in size. Smaller grains and higher linear density sug- gested that in this case densification process prevailed over undesirable process of grain coarsening, which finally resulted in im- proved mechanical properties of the scaffolds.
