The evaluation of miscibility of blends of poly(ether imide) (Ultem1000) and a copolyester of bisphenol-A with terephthalic and isophthalic acid (ArdelD-100) by viscosimetry

The intermolecular interactions and miscibility behavior between poly(ether imide) (Ultem^®1000) and a copolyester of bisphenol-A with a mixture of terephthalic and isophthalic acid (Ardel^®D-100) in compositions of 100/0, 80/20, 60/40, 40/60, 20/80 and 0/100 have been investigated in dilute solutions in chloroform. An Ubbelohde-type home-made viscometer was used to determine the specific viscosities of the blends in a constant temperature bath. Several viscosity interaction parameters used as the criteria of miscibility were determined from viscosity measurements. The parameters suggested that Ultem^®1000 and Ardel^®D-100 were miscible. The miscibility of the polymers was confirmed by the results of differential scanning calorimetry measurements.     

Antioxidant and antiproliferative activities of Helleborus odorus Waldst. & Kit, H. multifidus Vis. and H. hercegovinus Martinis

This study was undertaken in order to evaluate possible antioxidative and antiproliferative activities of three Helleborus taxa. The dry leaves and roots of three Helleborus taxa were extracted with ethanol and water. A phytochemical evaluation of the selected extracts was performed using spectrophotometric methods and a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity assay was used for measuring the antioxidative activity of extracts. The antiproliferative activity of the three Helleborus taxa was studied using Burkitt's lymphoma B cells (BJAB) cell lines. The phytochemical evaluation showed that the leaves contain high levels of total phenolic and flavonoid content. Results from the DPPH assay indicated that the activity of the ethanol and water extracts of the leaves was higher than that of positive control (thymol). Extracts from the roots of H. odorus also displayed higher antioxidant activity than the positive probe, while H. mulifidus and H. hercegovinus root extracts were less effective. A statistically significant correlation between total phenolic content and antioxidative properties indicates that these compounds contribute to the antioxidant activity. The highest percentage of cell growth inhibition was observed when testing the water root extracts of H. multifidus (50.14%) and H. hercegovinus (49.04%). In contrast, the water leaf extract of H. hercegovinus exhibited the lowest inhibition of cell growth (8.59%), although it showed strong antioxidant activity.     

Relaxation and Miscibility of the Blends of a Poly (Ether Imide) (Ultem™) and a Phenol-A-Based Copolyester (Ardel™) by Inverse Gas Chromatography

Inverse gas chromatography (IGC) was used to analyze the secondary transition temperatures and the miscibility of binary mixtures of poly (ether imide) (Ultem™) and a copolyester of bisphenol-A with terephthalic and isophthalic acids (50/50) (Ardel™) in three compositions (25/50, 50/50 and 75/25). Retention diagrams of the mixtures of Ultem™ and Ardel™ for n-nonane, n-decane, n-butyl acetate and isoamyl acetate were obtained at temperatures between 60 and 285 °C. Second-order transition temperatures of the mixtures were determined according to the slope change in retention diagrams of the solvents. The glass transition temperatures of the mixtures suggested the miscibility of the polymers. Polymer–polymer interaction parameters of binary mixtures of the polymers were determined at temperatures between 260 and 285 °C by Flory–Huggins theory. The polymer–polymer interaction parameters were dependent on the solvent used. The small values of polymer–polymer interaction parameters close to zero suggest some weak interactions between the polymers in the mixture. It was concluded that it was possible to obtain more meaningful information related to the interactions of polymers in a mixture from IGC measurements, if binary polymer–solvent interaction parameters of the used solvent probes were around 0.5.

     

Synthesis of boron carbon nitride layers for the adsorption of hazardous basic dye from aqueous solutions

Research on Chemical Intermediates - Many researchers have investigated the usage of carbonaceous materials as adsorbents. In this study, boron carbon nitride (BCN) was synthesized using boric acid...     

High-performance thin-layer chromatography determination of some antimycotic imidazole derivatives and preservatives in medicinal creams and a gel

Simple and reliable thin-layer chromatography-densitometry methods for determination of antimycotics (bifonazole, clotrimazole, and miconazole) and preservatives (benzyl alcohol and benzoic acid) were developed. The pairs bifonazole/benzyl alcohol, clotrimazole/benzyl alcohol, and miconazole/benzoic acid were determined simultaneously. The following mobile phases were used: ethyl acetate-n-heptane-methanoldiethylamine (3 + 4.5 + 1 + 0.2, v/v/v/v) for bifonazole and benzyl alcohol; n-butyl acetate-n-heptane-methanol-dietylamine (3 + 4.5 + 1 + 0.2, v/v/v/v) for clotrimazole and benzyl alcohol; and n-butyl acetate-carbon tetrachloride-methanol-diethylamine (3 + 6 + 2.5 + 0.5, v/v/v/v) for miconazole and benzoic acid. The chromatographic zones on silica gel plates were scanned in the reflectance/absorbance mode at 230 nm (bifonazole, benzyl alcohol, miconazole, and benzoic acid) and 210 nm (clotrimazole and benzyl alcohol). The recovery for all substances ranged from 98.7 to 100.7%. The limits of detection and quantitation were 0.03 to 0.2 microg and 0.1 to 0.5 microg/spot, respectively. The proposed methods were applied for determination of antimycotics and preservatives in commercially available pharmaceuticals.