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1

Influence of flavanone on the stabilization of ethylene-propylene elastomer

Zaborski M., Masek A., Chrzescijanska E.

Polimery

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2011

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T. 56, nr 7-8

558-563

EN

Antioxidating properties of flavanone were investigated with electroanalytical methods. Voltamperograms of flavanone oxidation on the Pt electrode reveal that along with increasing polarization rate the peak potential shifts slightly towards more positive potentials. The dependence of the peak current on the square root of the polarization rate is linear and the plot of the function passes through the origin of coordinates, which indicates no adsorption of the investigated substrate on the electrode and a diffusive control of the studied electrode reaction. To the ethylene-propylene elastomer (EPM) there were added 1.25 phr of flavanone and there was studied its impact on the stability of these blends subjected to thermal ageing and UV irradiation. The antioxidating efficiency of the investigated antioxidizer was established from changes in the deformation energy, crosslinking density and color of the EPM vulcanizates. Based on the results obtained, it was stated that flavanone performs its function well, providing good protection of the vulcanizates from oxidative processes.

PL

Metodami elektroanalitycznymi zbadano właściwości antyutleniające flawanonu (rys. 1—4, tabela 1). Woltamperogramy utleniania flawanonu na elektrodzie Pt wskazują, że wraz ze wzrostem szybkości polaryzacji potencjał piku przesuwa się nieznacznie w kierunku potencjałów bardziej dodatnich (rys. 2). Zależność prądu piku od pierwiastka z szybkości polaryzacji jest liniowa i przechodzi przez początek układu współrzędnych, co wskazuje na brak adsorpcji badanego substratu na elektrodzie i dyfuzyjną kontrolę badanej reakcji elektrodowej (rys. 3). Do elastomeru etylenowo-propylenowego (EPM) wprowadzano 1,25 phr flawanonu i badano jego wpływ na stabilność mieszanek EPM/flawanon poddawanych starzeniu termicznemu i działaniu promieniowania UV. Wydajność antyutleniającą badanego przeciwutleniacza sprawdzano określając zmiany energii deformacji, gęstości usieciowania oraz barwy wulkanizatów EPM. Na podstawie uzyskanych wyników stwierdzono, iż flawanon spełnia swoją funkcję, dobrze chroniąc wulkanizaty przed procesami oksydacyjnymi.

2

Photoelectrochemical Degradation of the Reactive Dye - Reactive Blue 81

Kusmierek E., Chrzescijanska E.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 7

1337-1351

EN

The results of photochemical, electrochemical and photoelectrochemical degradation of Reactive Blue 81 with the application of titanium electrodes covered with titanium and ruthenium oxides are presented in this paper. The influence of current density, process time and dye concentration on the photoelectrochemical degradation was investigated. The photochemical degradation of Reactive Blue 81 resulted only in a slight decolourization of the dye solution. The electrochemical oxidation improved the effective ness of the dye degradation but the complete mineralization was still not achieved. The combination of photochemical process with electrochemical oxidation at the titanium electrodes covered with titanium and ruthenium oxides, resulted in a significant mineralization of the dye solution. It did not require addition of any chemicals or difficult post-treatment processes the way it is necessary in the photodegradation with TiO2 used in the suspension mode.

3

Investigation of Reactive Blue 81 Electrooxidation at Various Electrode Materials - Kinetic Parameter

Chrzescijanska E., Kusmierek E., Nawrat G.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 6

1115-1126

EN

The electrochemical oxidation of Reactive Blue 81 proceeds easier at titanium electrodes covered with titanium and ruthenium oxides than at a platinum electrode. This process proceeds at both types of electrodes in at least one electrode step before potentials reach the value at which the oxygen evolution starts and is irreversible. Ruthenium oxide has electrocatalytic properties and titanium oxides has photocatalytic properties. An increase in the content of RuO2 at the surface of a titanium electrode causes electrooxidation of Reactive Blue 81 to proceed easier and quicker. The substrate is also reduced in at least two electrode steps at potentials higher than the potentials at which the hydrogen evolution starts. The reduction is also irreversible. An increase in pH of the dye solution facilitates the electrooxidation of Reactive Blue 81.