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1

Degradation of Polyvinylpyrrolidone by Solution Plasma Process

100%

Akyüz A., Özkan M.

Acta Physica Polonica A

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2017

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vol. 131

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issue 3

343-345

EN

The solution plasma technique, which has been recently invented by Takai and Saito, produces radicals, ions, UV photons, shock waves and metastable excited atoms. These generated active species are used as the source of some chemical reactions. The exact structure of the solution plasma is not well known at present, however it has been shown to be a versatile phenomenon for production of nanomaterials, sterilization and organic compound decomposition. Solution plasma technique has emerged as a great prospect for the chain scission (degradation) of polymers, to improve their solubility and physicochemical characteristics due to such advantages as absence of toxic materials, low temperature and usage of economical, simple equipment. In this study, polyvinylpyrrolidone, uncharged water soluble polymer of a known initial molecular weight, was continuously monitored using the continuous viscometry method, which gives the viscosity at any moment of the reaction, during the interaction of polyvinylpyrrolidone with plasma, for the first time in the literature.

2

Positronium Formation with Trapped Electrons in n-Alkanes

88%

Zgardzińska B., Goworek T.

Acta Physica Polonica A

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2011

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vol. 119

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issue 3

328-331

EN

Positronium (Ps) formation during self-irradiation by positrons was observed in n-alkanes of various carbon chain length. The rise of Ps intensity with time of irradiation is the result of positronium formation with trapped excess electrons. In the range T < 190 K the saturation value of positronium intensity changes with temperature mainly due to the change of positron mobility. With the increase of the irradiation dose the process of charging traps is slowing down and this effect is ruled mainly by interaction of excess electrons with ionization products during electron's migration to the traps.

3

Swelling, Mechanical and Antimicrobial Studies of Ag/P(HEMA/IA)/PVP Semi-IPN Hydrogel Hybrids

63%

Jovašević J., Dimitrijević S., Filipović J., Tomić S., Mićić M., Suljovrujić E.

Acta Physica Polonica A

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2011

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vol. 120

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issue 2

279-283

EN

A simple and fast approach to the design and production of new hybrid polymeric biomaterials with silver particles is presented in this work. Silver/semi-interpenetrating network hybrid hydrogels (Ag/semi-IPNHHs) were prepared through an optimized solution crosslinking copolymerization of 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA), in the presence of PVP, a silver salt and a reducing "green" agent (Ag/P(HEMA/IA)/PVP). PVP was chosen due to its protective, reduction, and nucleation properties in the production of metal particles. The structure of the Ag/semi-IPNHH was characterized by Fourier transform infrared spectroscopy (FTIR). The presence of silver and PVP in the network was confirmed by FTIR spectra. The results obtained by dynamic mechanical analysis (DMA) showed good mechanical properties for all samples. The swelling studies of Ag/P(HEMA/IA)/PVP were conducted in the temperature range of 25-55°C, in the buffer of pH 7.40. The Ag/semi-IPNHH showed temperature-sensitive swelling properties, with the lower critical solution temperature (LCST) values in the physiologically interesting interval. The antimicrobial activity of the samples was tested using E. coli, S. aureus and C. albicans pathogens. It was concluded that the antimicrobial potential depends on the hydrogel's composition and the type of microbes

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3 Acta Physica Polonica A

1 2017

2 2011

1 Akyüz A.

1 Dimitrijević S.

1 Filipović J.

1 Goworek T.

1 Jovašević J.

1 Mićić M.

1 Suljovrujić E.

1 Tomić S.

1 Zgardzińska B.

1 Özkan M.

Degradation of Polyvinylpyrrolidone by Solution Plasma Process

Positronium Formation with Trapped Electrons in n-Alkanes

Swelling, Mechanical and Antimicrobial Studies of Ag/P(HEMA/IA)/PVP Semi-IPN Hydrogel Hybrids