Synthesis, characterization, and Ni(II) ion sorption properties of poly(styrene-co-divinylbenzene) functionalized with aminophosphonic acid groups

In this study, novel chelating resins containing aminophosphonic acid groups grafted on poly(styrene-co-divinylbenzene) (1 % or 15 % DVB) were obtained by “one-pot” reactions. The phosphorus contents were determined in order to calculate the degree of functionalization with pendant aminophosphonic acid groups. The fraction of repetitive units functionalized with aminophosphonic acid groups was determined by accepting the statistical structure of the repetitive unit of initial and final copolymer. These materials were characterized by FT-IR spectroscopy, EDX, and TGA. Adsorption properties of aminophosphonic acids grafted on poly(styrene-co-divinylbenzene) were examined for the removal of Ni(II) ions from aqueous solutions using the batch equilibrium procedure. By applying the kinetic models to the experimental data it was found that the adsorption of Ni(II) on the studied chelating resins is described by the pseudo-second-order kinetic model. For all the studied systems, Langmuir isotherm model provided an excellent fit of the equilibrium adsorption data.     

Nanocrystalline BaAl2O4 powders prepared by aqueous combustion synthesis

In order to achieve BaAl₂O₄ formation via combustion synthesis, two types of recipes were designed: single fuel recipes (urea, glycine, β-alanine or hexamethylenetetramine) and innovative fuel mixture recipes (urea+glycine, urea+β-alanine and urea+hexamethylenetetramine respectively). No combustion reactions were noticed in the case of single fuel recipes based on urea or hexamethylenetetramine. The only crystalline phase present in the case of the powders obtained in such a way was unreacted Ba(NO₃)₂. Glycine and β-alanine generated smoldering reactions, leading to the formation of black powders, which consist of Ba(NO₃)₂, BaCO₃ and traces of BaAl₂O₄ (in the case of β-alanine). Fuel mixture recipes proved to be better than single fuel recipes, yielding BaAl₂O₄ as main crystalline phase. The specific surface area of the resulted powders ranges between 2.0 and 3.9 m²/g. The urea and glycine fuel mixture was the most efficient yielding BaAl₂O₄ with an average crystallite size of 60 nm.     

Synthesis,characterization, and adsorption behavior of aminophosphinic grafted on poly(styrene‐Co‐divinylbenzene) for divalent metal ions in aqueous solutions

In the present work, two novel aminophosphinic acid ligands grafted on poly(styrene‐1%divinylbenzene) (St‐1%DVB) have been synthesized by reacting polymer precursors bearing primary amino groups with benzaldehyde (or propionaldehyde) and phenylphosphinic acid by the “one‐pot” Kabatachnik‐Fields reaction. The resins functionalized with aminophosphinic pendant groups were characterized by means of Fourier transform infrared spectroscopy (FTIR), thermal analysis, energy dispersive X‐ray microanalysis (EDX), and Scanning electron microscopy (SEM) imaging. Its adsorption capacity for divalent metal ions such as Cu(II) and Ni(II) were investigated. The adsorption procedure of Cu(II) and Ni(II) ions on polymer‐grafted aminophosphinic acid ligands was carried out by batch experiments. The result also shows that the adsorption process was best described by a pseudo‐second‐order kinetic equation and by the Langmuir adsorption isotherm. The best maximum adsorption capacity was obtained for resin with aminobenzylphosphinic acid groups [1.46 mg Cu(II)/g and 1.36 mg Ni(II)/g]. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Grafting of Hindered Amine Stabilizer in Poly(propylene) Films under γ‐Irradiation

Summary: In this paper, the grafting of a hindered amine stabilizer (HAS) is studied in isotactic poly(propylene) (PP) films under γ‐irradiation. The HAS used has a definite structure that combines a hindered amine functionality and a UV‐absorbing unit (benzylidene malonate ester group) detectable at 308 nm in the UV spectrum of PP film and 314 nm in chloroform. The stabilizer is added to the polymer at various concentration ratios: 0.1, 0.2, and 0.3 wt.‐%. The percentage of HAS grafting in the PP film at various additive concentrations is determined as a function of γ‐radiation dose in the range of 0–100 kGy by direct spectroscopic measurements through the absorption band of the stabilizer in the UV spectra of the PP film. The percentage of free HAS extracted with chloroform from the PP film versus the radiation dose is determined by UV spectroscopy for all the additive concentrations used. This study reveals that only 80% of the HAS is grafted on the 100 kGy irradiated PP matrix independent of the additive concentration used. However, the percentage of HAS grafted on PP films displays an exponential dependence on γ‐radiation dose. These results are consistent with the data obtained on the free HAS content. γ‐Irradiation grafting of HAS in the PP is accompanied by the oxidative degradation of the polymer substrate that is evaluated by increasing the carbonyl index and reducing significantly the oxidation induction time of the PP films.

The percentage of hindered amine stabilizer grafted to the PP film as a function of γ‐radiation dose.     

Zur zerstörungsfreien Prüfung des Holzes durch Schwingungsversuche

Ohne Zusammenfassung     

Struktur und Reaktivität heterosubstituierter Nitrile. 24 Kinetik und Mechanismus der Reaktion von o-Phenylendiamin mit Arylcyanaten

Structure and Reactivity of Heterosubstituted Nitriles. 24. Kinetics and Mechanism of the Reaction of o-Phenylen diamine with Aryl Cyanates The second and third order rate constants for the reaction of o-phenylene diamine with aryl cyanates to 2-amino benzimidazole phenylester imide in water/dioxane have been determined by i.r. measurements. The reaction proceeds through a bimolecular and a trimolecular mechanism simultaneously. In the slow step of the bimolecular process an electrophilic attack of the aryl cyanate on o-phenylene diamine takes place in a seven membered cyclic transition state. The slow step of the trimolecular mechanism consists of a nucleophilic attack of the diamine on a phenole aryl cyanate associate by a six membered cyclic transition state. The final products of both reactions are formed by successive fast reactions.