Microwave-Assisted Synthesis of Modified Glycidyl Methacrylate–Ethyl Methacrylate Oligomers, Their Physico-Chemical and Biological Characteristics

In this study, well-known oligomers containing ethyl methacrylate (EMA) and glycidyl methacrylate (GMA) components for the synthesis of the oligomeric network [P(EMA)-co-(GMA)] were used. In order to change the hydrophobic character of the [P(EMA)-co-(GMA)] to a more hydrophilic one, the oligomeric chain was functionalized with ethanolamine, xylitol (Xyl), and L-ornithine. The oligomeric materials were characterized by nuclear magnetic resonance and Fourier transform infrared spectroscopy, scanning electron microscopy, and differential thermogravimetric analysis. In the final stage, thanks to the large amount of -OH groups, it was possible to obtain a three-dimensional hydrogel (HG) network. The HGs were used as a matrix for the immobilization of methylene blue, which was chosen as a model compound of active substances, the release of which from the matrix was examined using spectrophotometric detection. The cytotoxic test was performed using fluid extracts of the HGs and human skin fibroblasts. The cell culture experiment showed that only [P(EMA)-co-(GMA)] and [P(EMA)-co-(GMA)]-Xyl have the potential to be used in biomedical applications. The studies revealed that the obtained HGs were porous and non-cytotoxic, which gives them the opportunity to possess great potential for use as an oligomeric network for drug reservoirs in in vitro application.

A Preliminary Study on the Synthesis of poly(vinylbenzyl chloride) with Different Solvents

Polyvinyl benzyl chloride (PVBC) was synthesized by free radical polymerization of 4-vinylbenzyl chloride using benzoyl peroxide initiator at 60 °C. PVBC was synthesised in different solvents such as toluene, xylene, 1,4-dioxane, and tetrahydrofuran. The polymers were structurally characterized by 1H NMR and FTIR spectroscopic techniques. The thermal property of the polymer was investigated by thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTA).The number average molecular weight, weight average molecular weight and polydispersity index of PVBC synthesised in different solvents were determined and compared by gel permeation chromatography technique.

Structural Construction of Binders Based on Orthophosphoric Acid and Refractory Materials

The formation of phosphate binders in systems based on orthophosphoric acid and the most common refractory fillers in foundry technology (quartz dust, zircon ZrSiO4, and kyanite-sillimanite Al2SiO5) has not been previously studied. The phase composition of these inorganic binders was studied, and the formation of silicon SiP2O7 and zirconium ZrP2O7 pyrophosphates was confirmed. The study by differential thermogravimetric analysis in the temperature range of 20–1000°С established the fact that the formed binders are thermally stable and do not emit harmful gaseous substances. The obtained results of the studied binders make it possible to develop new environment-friendly core mixtures of thermal hardening.

Preparation and properties of solid electrolyte CaxBi1.7−xW0.3O3.45−0.5x electrolyte material by sol–gel combution method

CaxBi[Formula: see text]W[Formula: see text]O[Formula: see text] (CBW) ([Formula: see text], 0.05, 0.10, 0.15, 0.20, 0.30) electrolyte material were synthesized by sol–gel self-combustion method. The samples were characterized by thermogravimetric-differential thermogravimetric analysis(TG-DSC), X-ray diffraction, scanning electron microscopy (SEM), porosity and electrochemical impedance spectroscopy (EIS). The results show the powders CaxBi[Formula: see text]W[Formula: see text]O[Formula: see text] (CBW) with fluorite crystal structure can be obtained after the precursor was calcined at 760∘C. When sintered at 780∘C for 2[Formula: see text]h, the compact ceramic sintered with relative density higher than 97% can be obtained. The electrochemical studies showed that CaxBi[Formula: see text]W[Formula: see text]O[Formula: see text] (CBW) have high ionic conductivity after 780∘C sintering. The sample Ca[Formula: see text]Bi[Formula: see text]W[Formula: see text]O[Formula: see text] exhibits a conductivity of 0.07978 S[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] at 750∘C, and the activation energy is 0.845[Formula: see text]eV, which is expected to be applied to the electrolyte materials for intermediate temperature solid oxide fuel cells (SOFC).

Characterization of clays and the technology of Roman ceramics production

ABSTRACTThe recent discovery of a Roman ceramics manufacturing workshop at Montelabate (Perugia, Italy), in use from the first century BC until the late-fourth to fifth centuries AD, offers a unique opportunity to study the technical processes for producing Roman amphorae. Ancient and modern clays were sampled and analysed; they do not differ significantly, supporting the hypothesis of the exploitation of the rich local clay source that allowed a continuity of production. Characterization of the clays was performed using geotechnical methods (Atterberg limits and size distribution) and by thermogravimetric and differential thermogravimetric analysis, Fourier-transform infrared spectroscopy, X-ray diffraction and X-ray fluorescence analyses. The material was suitable for pottery making with the addition of calcite and quartz sand temper. Production waste and discarded materials as well as good-quality products were also analysed with the same methodology. It is therefore possible to reconstruct the ancient technology by defining the recipe for the production of the amphorae and their firing temperature on the basis of the decomposition of clay materials and the presence of newly formed minerals.

Effect of ZnSO4 and MnSO4 on the Growth of Sulphamic Acid Single Crystals

Single crystals of Sulphamic Acid doped with Zinc Sulphate and Manganese Sulphate were grown at room temperature using slow evaporation technique. Structural analysis of the grown crystals was done using single crystal X Ray Diffraction and powder X Ray Diffraction studies. Various functional groups seen in the grown crystals are determined using FTIR spectroscopic analysis. The cut-off wavelength of ZnSO4 and MnSO4 doped Sulphamic acid were evaluated by UV-Vis-NIR spectral studies. Thermal behaviour of the grown crystals was identified from Thermogravimetric Analysis (TGA) and Differential Thermogravimetric Analysis (DTA). The mechanical strength and Second harmonic generation of the grown crystals was identified by Vicker’s Microhardness Test and Kurtz powder technique respectively.

Desorption characteristics and kinetic parameters determination of molecular sieve by thermogravimetric analysis/differential thermogravimetric analysis technique

The kinetics of the thermal desorption of CO2 adsorbed on zeolite 13X were obtained using a differential thermogravimetric analyser under two different carrier gas conditions. The varying heating rates were set as 8, 12, 16, and 20 K min−1, respectively. The desorption activation energy of the physisorption sites for this experiment evaluated by an integral method without prediction of the reaction order ranged from 12.15 to 14.12 kJ mol−1 (CO2 as the carrier gas) and 43.32 to 50.42 kJ mol−1 (Ar as the carrier gas), respectively. The desorption activation energy of the chemisorption sites ranged from 57.95 to 58.53 kJ mol−1 (CO2 as the carrier gas) and 74.02 to 79.92 kJ mol−1 (Ar as the carrier gas), respectively.

Nature and adsorption capacity of banana leaf rim carbon

The activated charcoal (AC) was synthesized from banana leaf rim (BLR) through three activation methods; physical (BLRC), chemical (Z BLRC, zinc chloride) and microwave activation (MW BLRC). The AC was characterized using fourier transform infrared spectrometer (FT-IR), Thermogravimetric analysis (TGA) & Differential thermogravimetric analysis (DTA) instrument and Field emission scanning electron microscope (FE-SEM). The Z BLRC has better thermal stability and adsorbent character compared with BLRC or MW BLRC. The present work is confined to an investigation on the adsorption process of Malachite green dye onto BLRC, Z BLRC & MW BLRC. Factors affecting adsorption process were studied and results that adsorption increases with concentration of dye, agitation time and temperature. This experimental data satisfied the Langmuir adsorption isotherm model. Second order kinetics holds good for the present adsorption process. Thermodynamic parameters were (∆H‡, ∆S‡ & ∆G‡) evaluated. Based on the characterization and adsorption experimental result it may be concluded that Z BLRC has better adsorption capacity than BLRC or MW BLRC.