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Accelerated Ageing of Newsprint Paper: Changes in Swelling Ability, WRV and Electrokinetic Properties of Fibres

Jablonský M., Botková M, Šutý Š, Šmatko L, Šima J.

Fibres & Textiles in Eastern Europe

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2014

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Vol. 22, no. 2 (104)

108--113

EN

The present paper deals with the effect of accelerated ageing on the ability of fibres to undergo saturation with water and the corresponding swelling kinetics. Changes in the surface charge of aged paper fibres were also investigated. Accelerated ageing was performed with newsprint paper at 98 °C and 50% RH during 0, 3, 5,7, 10, 15, 20 and 30 days. The rate and maximum swelling of accelerated aged paper in water were obtained with a modified monitoring unit measuring wood swelling ability. Since paper swells extremely fast in water, even at 30 °C, this apparatus made it possible for the first time to obtain accurate kinetic data on aged paper swelling in water. The polyelectrolyte titration technique was used to investigate changes in the surface charge on fibres from accelerated aged paper.

PL

Praca dotyczy efektów przyspieszonego starzenia papieru gazetowego na zdolność włókien do nasycenia wodą związanego z kinetyką spęczniania. Badano również zmiany w ładunkach powierzchniowych włókien po przyspieszonym starzeniu. Szybkość oraz maksymalną wielkość spęcznienia badano za pomocą zmodyfikowanego przyrządu służącego do badania pęcznienia drewna. Biorąc pod uwagę, że papier pęcznieje w wodzie ekstremalnie szybko, badania prowadzone wspomnianym przyrządem pozwoliły po raz pierwszy określić pęcznienie papieru z dużą dokładnością. Technika miareczkowania polielektrolitycznego pozwoliła zbadać zmiany w ładunkach powierzchniowych.

2

Speciation and Spectra of Bromokojatoiron(III) Complexes in Aqueous Solutions

Šima J., Šípoš R., Izakovic M., Valigura D., Tarapeík P.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 12

1991-1999

EN

The formation of iron(III) complexeswith chelating bromokojate anions L– was investigated in aqueous solutions as a function of the pH and c(Fe3+) : c(HL) molar ratio. Stability constants of the complexes [FeL(H2O)4]2+, [FeL(H2 O)3(OH)]+, [FeL2 (H2O)2]+, [FeL2(H2O)(OH)] and [FeL2(OH)2]– were determined by the evaluation of UV-VIS spectral data. Based on the stability constants, distribution of the above complexes, [Fe(H2O)6]3+, and [Fe(H2O)5(OH)]2+ in solutions of various composition were calculated. The paper indicates a compatibility of the used data treatment and that not taking hydroxo complexes into account. Properties of the investigated bromokojic acid and its iron(III) complexes are compared to those required for therapeutic application as alternative iron chelators.

3

Bell-shaped Dependence of the Quantum Yield of Fe(II) Formation in Irradiated Methanolic Solutions of Iron(III) Azido Methanolic Solutions of Iron(III) Azido Complexes with N, N'-Ethylenebis(benzoylacetoneiminato) Schiff Base Derivatives

Šima J., Horváthová L.

Polish Journal of Chemistry

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2003

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Vol. 77 / nr 12

1857-1865

EN

The complexes trans-[Fe(4-R-benacen)(CH3OH)N3], where 4-R-benacen2- are tetradentate open-chain N2O2-Schiff base N,N'-ethylenebis(4-R-benzoylacetoneiminato) ligands (R =H, Cl, Br,OCH3, CH3) are redox stable in the dark. Under the impact of ultraviolet and/or visible radiation they undergo photochemical reactions, yielding Fe(II) and formaldehyde CH2O as final products. As an intermediate, _CH2OH radicals were identified by EPR spin trapping technique. The efficiency of the photoredox processes, expressed by the quantum yield of Fe(II) formation, Fi Fe(II) is strongly wavelength dependent and influenced by the peripheral groups R of the tetradentate ligands. It was found, that along with a frequently observed decrease in the quantum yield with decreasing the photon energy of incident radiation (Fi Fe(II) at 313 nm < Fi Fe(II) at 366 nm