New melamine–formaldehyde–ketone polymers. III. Coatings from melamine and reactive solvents based on cyclohexanone

The conditions and methods of preparing novel melamine–formaldehyde–cyclohexanone coatings are presented. The coatings were prepared by dissolving melamine in reactive solvents based on formaldehyde and cyclohexanone. The latter were prepared at different molar ratios of the components. The water resistance of the resulting coatings was measured. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1083–1092, 2006     

Synthesis and characterization of resins with ligands containing guanidinine derivatives. Cu(II) sorption and coordination properties

A new modification direction of acrylonitrile, vinyl acetate and divinylbenzene terpolymers (A, B) are presented. The aminolysis of nitrile groups of the terpolymers using ethylenediamine or hydroxylamine hydrochloride was a first stage of the modification. The resulting amine groups reacted with dicyandiamide (DCDA), cyanamide (CA) and sodium dicyanimide (SDC) in order to obtain the biguanidyl, guanidyl or nitrilguanidyl derivatives in the polymer side chain, respectively. The properties of all obtained resin such as water regain, nitrogen content, amine and carboxyl group concentration and sorption properties towards Cu(II) from nitric acid solutions were determined. The studies of IR spectra of all the resins were performed. Structures of ligand complexes with Cu(II) were studied using electron paramagnetic resonance spectroscopy.     

Sorption of heavy metal ions from aqueous solutions in the presence of EDTA on monodisperse anion exchangers

Conventional precipitation methods of industrial sewage and wastewater purification are not very effective and are insufficient in many cases. This implies the necessity of searching new, effective methods exploiting cheap, accessible and ecologically safe ion exchangers and sorbents. The paper presents the studies on removal of heavy metal ions — Cu(II), Zn(II), Co(II), Ni(II) and Fe(III) — from aqueous solutions in the presence of EDTA carried out on commercially available, strongly basic monodisperse anion exchangers with the polystyrene skeleton gel, Lewatit MonoPlus M 500; and the macroporous, Lewatit MonoPlus MP 500, which are more widely applied in water purification processes. The research results indicate a high affinity of the Lewatit MonoPlus M 500 and Lewatit MonoPlus MP 500 anion exchangers in the chloride form for copper(II), nickel(II), cobalt(II) and zinc(II) complexes with EDTA. The affinity series for the heavy metal complexes in the 0.001 M M(II)/(III)–0.001 M EDTA and 0.001 M M(II)/(III)–0.001M EDTA–0.001 M–0.002 M NaOH systems were found for the Lewatit MonoPlus M 500 anion exchanger in the chloride form to be as follows: Cu(II) > Ni(II) > Co(II) > Zn(II) Fe(III). In the case of the Lewatit MonoPlus MP 500 anion exchanger in the chloride form there was found the following affinity series: Cu(II) > Co(II) > Ni(II) > Zn(II) Fe(III). These anion exchangers can be applied in the removal of copper(II) complexes from waters and wastewaters.     

Small Alterations in Cobinamide Structure Considerably Influence sGC Activation

Specially designed B‐ring‐modified cobalamin derivatives were synthesized and tested as potential activators of soluble guanylyl cyclase (sGC). Herein, we disclose the influence of substituents at the c‐ and d‐positions in hydrophilic and hydrophobic cobyrinic acid derivatives on their capacities to activate sGC. The presence of the amide group at c‐/d‐position in cobyrinic acid derivatives strongly influence the level of sGC activation. Removal of the d‐position altogether has a profound effect for hydrophobic compounds. In contrast, little differences were observed in hydrophilic ones.     

Characterization of Pure and Modified TiO_{2} Layer on Glass and Aluminum Support by Beam Deflection Spectrometry

\(\mathrm {TiO}_{2}\) thin films used as photocatalysts in environmental applications were studied by beam deflection spectroscopy (BDS) and by atomic force microscopy. A novel multiparameter theoretical model was developed in order to explain BDS experimental data. The fundamental parameters of examined films: thermal diffusivity, thermal conductivity, and charge transport properties such as the value of the energy bandgap, carrier lifetime, concentration, and type of dopants, were obtained as results of the modeling of BDS data. With BDS, we observed that the material’s thermal conductivity and thermal diffusivity depend also on the porosity and the surface roughness of films. Consequently, the photocatalytic performance can be estimated by measuring the thermal diffusivity of films. Furthermore, we found that surface roughness is prone to changes when the film is used as photocatalysts in water purification processes. During the purification process, the roughness decreases and the photocatalytical performance drops. Moreover, it was discovered that the thermal, electrical, and morphological properties of photocatalysts films depend on the support to which the \(\mathrm {TiO}_{2}\) layer is deposited. These complex relations demonstrate that knowledge of fundamental physical parameters is required in order to improve the photocatalytic performance of \(\mathrm {TiO}_{2}\) films. In this view, the BDS measurements offer a tool for noncontact and nondestructive evaluation of thermal and electronic parameters of thin film \(\mathrm {TiO}_{2}\) photocatalysts as demonstrated in this work.     

Occurrence of Campylobacter spp. in poultry and poultry products for sale on the Polish retail market

In 2007 and 2008, a monitoring study was carried out in Poland to examine the occurrence of thermotolerant Campylobacter spp. in raw and cooked chicken products available on the retail market. A total of 912 samples were tested: 443 samples of raw chicken meat, 146 samples of giblets, and 323 ready-to-eat poultry products (150 samples of spit-roasted chicken, 56 samples of smoked chicken, and 117 samples of paté and cold meats). A high level of contamination of raw chicken meat (51.7% of samples) and chicken giblets (47.3% of samples) was detected. However, thermotolerant Campylobacter spp. were found in only 1.2% of the ready-to-eat poultry products.     

The influence of powder morphology on the effect of rosemary aroma microencapsulation during spray drying

The influence of particle morphology of spray dried powders obtained by using different carriers on the efficiency of microencapsulation of rosemary aroma is shown in the present research. It was found that the type of the carrier influenced the size but not the shape of rosemary aroma capsules and all the capsules were spherical with cracks. The biggest particles, d₅₀ = 55 μm, were obtained with 25% maltodextrin (MD) as a carrier, and the smallest, d₅₀ = 29 μm with 30% gum arabic (GA). The efficiency of encapsulating aroma inside of the capsules depended on the particles size and apparent density. An increase in the quantity of microencapsulated aroma from 10% for 25% MD to about 60% for 30% GA as the carrier was seen, which co‐related with a decrease in the average diameter of the powder particles. Similarly, an increase in the efficiency of aroma retention was followed by an increase of apparent density of powders from 796 (25% MD) to 1156 kg m^?3 (30% GA).     

Application of monodispersive anion exchangers in sorption and separation of y3+ from Nd3+ and Sm3+ complexes with dcta

Rare earth complexes with trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid (DCTA) of the Ln(dcta)- ype exhibited an unusual sequence of affinity on the polystyrene anion exchangers: pm3 >Nd3 >Sm3 >pr3 >Ce3 >Eu3 >Gd3 >La3 >Sc3 >Tb3 >Dy3 >Ho3 >y3 >Er3 >Tm3 >yb3 >Lu3 [1]. Taking into account the position of Y3 , Sm3 , and Nd3 in this affinity series, for the monodispersive polystyrene anion exchangers, Lewafit MonoPlus M 500, Lewatit MonoPlus M 600, Lewatit MonoPlus MP 500, Lewatit MonoPlus MP 64,and for the heterodispersive anion exchanger, Lewatit MP 62, the weight (Dg,) and bed (Dv) distribution coefficients of these complexes and working ion exchange capacities (Cw) were determined. Based on these values, purifications of Y3 from Nd3 and y3 from Sm3 in the macro-micro component system on these anion exchangers were studied. The application potential of this method was highlighted for the separation of yz3 in the presence of Nd3 and Sm3 . With 1 L of monodispersive and strongly basic polystyrene gel anion exchanger Lewatit MonoPlus M 500 in the acetate form, it is possible to obtain approximately 79 g Y2O3 purified from Nd2O3 and 70 g Y2O3 purified from Sm2O3 in the same process condition.     

Flammability and thermal properties of rigid polyurethane foams with additionally introduced cyclic structures

Flammability, smoke evolution, thermal, and thermomechanical properties of low-density rigid polyurethane foams obtained from different aromatic polyols were investigated. The foams were prepared according to a standard formulation ensuring the same foam phosphorus content. Cellular polyurethanes with the best fire resistance were obtained from polyols containing disubstituted naphthalene and biphenyl rings. A linear equation was proposed to describe the influence of various structural units of the polyurethane (the content of cyclic structures C_c, nitrogen content C_N, and crosslinking equivalent M_c) upon its flammability, expressed in terms of its oxygen index (OI) Thermal stability of crosslinked polyurethanes was not found to influence significantly their thermomechanical properties, while crosslink density and the type and quantity of cyclic structures additionally introduced did have a pronounced effect upon these properties.