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1

Investigation into the Surface Properties of Papers Sized with Styrene-Acrylate-Cationic Monomer Based Terpolymers

100%

Özdemir M., Aytaç A., Deniz V.

Acta Physica Polonica A

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2017

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vol. 131

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issue 1

178-181

EN

In this study, styrene(St)/2-ethyl hexyl acrylate(2-EHA) based surface sizing materials were developed with four different cationic monomers (CM), namely diallyldimethyl ammonium chloride (DADMAC), [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MATMAC), [3-(methacryloylamino) propyl]-trimethyl ammonium chloride (MAPTAC), (viniylbenzyl) trimethyl-ammonium chloride (VBTMAC). Ternary polymerization was realized with emulsion polymerization, by using 2,2'-azobis (2-methylpropionamidine) dihydrochloride (A) as initiator. Thermal properties of the synthesized terpolymers were determined with differential scanning calorimeter and thermal gravimetric analysis. Differential scanning calorimeter results showed that glass transition temperature (T_{g}) values of polymers were not dependent on the types of cationic monomers, and were found about 44-45°C. Ion exchange capacities of the terpolymers were determined. The latexes produced were used as sizing materials for paper surface treatment. Then critical surface properties of the papers sized such as water resistance (Cobb value) and contact angle were measured. It was found that the best, i.e. the lowest Cobb results were obtained when MATMAC and MAPTAC cationic monomers were used in terpolymers.

2

Poly(ethylene glycol dimethacrylate-co-1-vinyl-1,2,4-triazole/ carbon nanotube, single-walled)/n-GaAs Diode Formed by Surface Polymerization

100%

Ahmetoglu M., Kara A., Kucur B.

Acta Physica Polonica A

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2016

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vol. 130

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issue 1

206-208

EN

Poly(ethylene glycol dimethacrylate-co-1-vinyl-1,2,4-triazole/carbon nanotube, single-walled)/n-GaAs ([P(EGDMA-VTAZ)-CNSW]/n-GaAs) diode was fabricated by using surface polymerization method. Electrical properties were carried out at several temperatures. Dark current mechanisms were investigated by using current-voltage (I-V) measurements. It was shown that the fabricated structure exhibited rectification behaviour that makes it a good candidate for electronic device applications.

3

Nonlinear Characterization of Safranin O Dye for Application in Optical Limiting

80%

Balaji G., Rekha R., Ramalingam A.

Acta Physica Polonica A

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2011

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vol. 119

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issue 3

359-363

EN

The optical nonlinearity of safranin O dye in methanol solution at different concentrations and as a solid film with polymethylmethacrylate (PMMA) has been studied using cw Nd-YAG laser at 532 nm as the source of excitation. The optical responses were characterized by measuring the intensity dependent refractive index (n_2) of the medium using the Z-scan technique. The open aperture Z-scan trace of the dye in solution and solid sample displayed saturable absorption. The closed aperture Z-scan trace of the dye exhibited a negative (defocusing) nonlinearity. The nonlinear refractive index was found to vary with concentration. Optical limiting characteristics of the dye at various concentrations in solution were studied. The nonlinearity appears to be of thermal origin.

4

Electric and Magnetic Properties of Hydrogels Doped with Cu Ions

70%

Coşkun R., Okutan M., Yalçın O., Kösemen A.

Acta Physica Polonica A

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2012

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vol. 122

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issue 4

683-687

EN

The electric and magnetic properties of Cu doped and pure/undoped hydrogels were investigated by impedance spectroscopy and electron spin resonance techniques, respectively. The capacitance and dissipation factor (tan δ) were measured in the frequency range of 100 Hz-10 MHz at room temperature. The Cole-Cole plots for the Cu doped dry and pure dry hydrogels have been used to describe the characteristic change of electrical properties in mentioned temperature interval. The comparison between Cu ions doped and pure/undoped samples is done using the impedance spectroscopy and the electron spin resonance techniques. Electron spin resonance signal for pure, Cu doped wet and Cu doped dry samples are not any power absorption signal, near the symmetric with respect to the resonance field values according to the dry sample and asymmetric for resonance field/base line, respectively.

5

Structural Changes in Surface-Modified Polymers for Medical Applications

70%

Pamula E., Dryzek E.

Acta Physica Polonica A

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2008

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vol. 113

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issue 5

1485-1493

EN

Biological properties of synthetic polymers can be improved by surface modification with the use of liquid oxidizers. A resorbable biomedical polymer - poly(glycolide-co-ε-caprolactone) (PGCL) was incubated in 0.1 M NaOH for 2, 6, 16, and 24 h, followed by excessive washing and drying in vacuum. Surface properties of the materials before and after modification were evaluated: wettability by contact angle measurements, topography by atomic force microscopy, and chemical functions by infrared spectroscopy. Applied modification improved wettability of PGCL due to creation of chemical oxygenated functionalities, and resulted in a slight alternation of the surface topography and roughness. In order to determine whether NaOH incubation caused structural changes in bulk of PGCL, positron annihilation lifetime spectroscopy, differential scanning calorimetry and viscosity measurements were performed. It was found that the ortho-positronium lifetime in PGCL declines as a function of modification time. It suggests that NaOH incubation causes structural changes in PGCL not only on the surface but also in bulk.

6

Hydrolytic Degradation of Poly(L-Lactide-co-Glycolide) Studied by Positron Annihilation Lifetime Spectroscopy and Other Techniques

61%

Pamuła E., Dryzek E., Dobrzyński P.

Acta Physica Polonica A

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2006

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vol. 110

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issue 5

631-640

EN

Changes of the poly(L-lactide-co-glycolide) structure as a function of degradation time in phosphate-buffered saline for 7 weeks were investigated by gel permeation chromatography, differential scanning calorimetry, nuclear magnetic resonance (^1H NMR), and positron annihilation lifetime spectroscopy. Surface properties as wettability by sessile drop and topography by atomic force microscopy were also characterized. Chain-scission of polyester bonds in hydrolysis reaction causes a quite uniform decrease in molecular weight, and finally results in an increase in semicrystallinity. Molecular composition of the copolymer and water contact angle do not change considerably during degradation time. Atomic force microscopy studies suggest that the copolymer degrades by "in bulk" mechanism. The average size of the molecular-level free volume holes declines considerably after one week of degradation and remains constant till the sixth week of degradation. The free volume fraction decreases as a function of degradation time.

7

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

51%

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

8

Structural Identification of Polymer Nanocomposites

51%

Bilewicz M., Labisz K., Tański T., Konieczny J., Górniak M.

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vol. 126

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issue 4

895-901

EN

Composites and nanocomposites as commercially used engineering materials with continuous development, are important for rising market and industry needs. Significant role is played by polymers, whose consumption increases every year, thanks to low cost of production, economical processing and broad scope of material composition possibilities, including nanomaterials and basing on them nanocomposites. Nanocomposites, using power of nanotechnology, may improve physical, chemical and mechanical properties, comparing to composites. Investigation of structure and properties of such materials is necessary to obtain knowledge about phenomena at micro and nanoscale and gives opportunity to design and control structure, because the properties of any material depend on its matter. Polymer matrix nanocomposites are interesting and very promising class of polymer composites. Investigation of structure development due to different heat treatment and under different processing condition of injection molded specimens of polypropylene and montmorillonite composition has been performed. Dispersion of nanoreinforcement, in the shape of 2:1 layer silicates, was observed under transmission and scanning electron microscope. Application of advanced technology of multiplication of oriented layer mostly reinforcing and orienting micro and nanoparticles along polymeric specimen, allowed to obtain several layers and significantly reinforced material. Light microscope has been used for observation layered zone, visible just in polarization mode.

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Investigation into the Surface Properties of Papers Sized with Styrene-Acrylate-Cationic Monomer Based Terpolymers

Poly(ethylene glycol dimethacrylate-co-1-vinyl-1,2,4-triazole/ carbon nanotube, single-walled)/n-GaAs Diode Formed by Surface Polymerization

Nonlinear Characterization of Safranin O Dye for Application in Optical Limiting

Electric and Magnetic Properties of Hydrogels Doped with Cu Ions

Structural Changes in Surface-Modified Polymers for Medical Applications

Hydrolytic Degradation of Poly(L-Lactide-co-Glycolide) Studied by Positron Annihilation Lifetime Spectroscopy and Other Techniques

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

Structural Identification of Polymer Nanocomposites