The objective of our investigations consists in the thermal characterization of SiO2-PbO-Na2O vitreous materials in order to establish their properties for applications mainly as sealants. In order to evaluate the vitreous material − metal adherence, the thermal expansion coefficients (α) from experimental and theoretic data were determined. The differential thermal analysis of studied materials give the information about temperatures characteristic to glass transition, crystallization and melting. Dilatometer measurements were performed in air atmosphere in order to establish thermal coefficients of the materials. Softening and flowing characteristic of the vitreous materials were established by heating microscope measurements. The difference between thermal expansion coefficient (α) of the vitreous materials (10.2 × 10−6K−1 and 17.6 × 10−6K−1) and thermal expansion coefficient of the steel substrate OL 38 (10.8 × 10−6K−1) is under 37%. This value is fit for a good adherence between materials.
The effect of gel preparation and heat treatment on the structural and optical properties of SiO2-ZnO materials prepared by the sol–gel method was investigated. Zinc acetate dehydrate, TEOS (tetraethylortosilicate), ethanol, distillated water and HCl were used as a starting material, solvent and catalyst, respectively. Four powders (G1–G4) were prepared in different ways from the starting materials mentioned above. The method of adding Zn precursors during the synthesis differed from one another. For the G1 synthesis, only Zn acetate powder was employed; for the G2 synthesis, Zn acetate was dissolved in distilled water; and for the G3 synthesis, Zn acetate was dissolved in ethanol. When synthesizing G4, TEOS was added last, after Zn acetate had been combined with water and ethanol. The SiO2-ZnO materials were dried at 200 °C and then heat-treated at 700 °C and 900 °C. All samples were investigated by X-ray diffraction and infrared spectroscopy in order to investigate their structure. SEM measurements were performed to investigate the morphology of materials. Optical properties were influenced by gel preparation and heat treatments. A reflectance of over 60% was obtained for G3 and G4 powders, while for G1 and G2, the reflectance was below 30%. In conclusion, synthesis steps and heat treatment can control the structure and properties of the powders.
In recent years, the rising number of bone diseases which affect millions of people worldwide has led to an increased demand for materials with restoring and augmentation properties that can be used in therapies for bone pathologies. In this work, PMMA- MBG composite scaffolds containing ceria (0, 1, 3 mol%) were obtained by the phase separation method. The obtained composite scaffolds were characterized by X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. UV–Vis measurement and EDX analysis confirmed the presence of cerium ions in the composite scaffolds. Evaluation of the in-vitro biocompatibility using MTT assay showed that composite scaffold containing 1 mol% of ceria presented higher viability than control cells (100%) for concentrations ranging between 5 and 50% after 96 h of incubation.
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