Institute of Heavy Organic Synthesis

Kędzierzyn-Koźle, Poland

Institute of Heavy Organic Synthesis

Kędzierzyn-Koźle, Poland
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Grueso E.,University of Seville | Kuliszewska E.,Institute of Heavy Organic Synthesis | Roldan E.,University of Seville | Perez-Tejeda P.,University of Seville | And 2 more authors.
RSC Advances | Year: 2015

The DNA conformational changes induced by different members of the N,N′-bis(dimethyldodecyl)-α-ω-alkanediammonium dibromide series (m-s-m, m = 12, s = 3 and 6) and the analogous series of hexadecyl gemini surfactants (m = 16, s = 3 and 6) were investigated in aqueous media by means of circular dichroism (CD), zeta potential, dynamic light scattering (DLS), viscometry, and atomic force microscopy (AFM) methods. The measurements were carried out by varying the gemini surfactant-DNA molar ratio, R = Cm-s-m/CDNA. For the conditions investigated two significantly different conformational changes were observed, the second of them being worth noting. At low molar ratios, all methods concurred by showing that gemini surfactants were able to form ordered aggregates which precedes DNA compaction. The second effect observed, at high molar ratios, corresponds to the transition from the compact state to a new more extended conformation. The degree of decompaction and the morphologies of the visualized structures are different not only depending on the surfactant tail's length, but also on the spacer's length. The results obtained for the 16-3-16/DNA and 16-6-16/DNA systems point out that the compaction/decompaction processes are somewhat different to those previously visualized for the analogous monoquaternary chain surfactant CTAB. This journal is © 2015 The Royal Society of Chemistry.

Wojtala A.,Institute of Heavy Organic Synthesis | Szablicki D.,University of Opole | Semeniuk I.,Institute of Heavy Organic Synthesis | Sudol M.,University of Opole | Sabura E.,Institute of Heavy Organic Synthesis
Fire and Materials | Year: 2015

Flame retardant composites must perform their protective roles permanently, also under conditions of intermittent or long-term exposure to sunlight, moisture or increased temperature. The aim of our work was characterization of the thermo-oxidative ageing (90 °C) and the changes in flammability of ethylene-vinyl acetate copolymer composites with 40 and 60 wt.% of magnesium hydroxide. The neat polymer and its composites were investigated for their thermal (DSC) and structural (FTIR) characteristics as well as their density, melt flow index, tensile properties and combustibility during ageing test. As FTIR results identified the different carbonyl groups in copolymer were created, the highest oxidation intensity was observed for neat copolymer. That process was accompanied by the scission of the polymer macromolecules, especially for first 700 h of thermal ageing. Thermo-oxidative ageing resulted also in the reduction of flammability of the test materials. The highest reduction was observed for neat polymer. The changes in some properties as analysed both for the copolymer and for its composites after over 700 h of ageing were indicative for initiation of cross-linking of copolymer molecules after that time. Copyright © 2014 John Wiley & Sons, Ltd.

Wojtala A.,Institute of Heavy Organic Synthesis | Czaja K.,University of Opole | Sudol M.,University of Opole | Semeniuk I.,Institute of Heavy Organic Synthesis
Journal of Applied Polymer Science | Year: 2012

Polyethylene grafted with itaconic acid was subjected to weathering under laboratory accelerated conditions. The course of the photo-oxidative degradation process of that material was studied by FTIR spectroscopy both through quantitative measurements of changes in absorbance values at selected wave numbers and through measurements of surface area values for absorption bands which were separated by means of deconvolution. The use of both those procedures of quantitative determinations resulted in a general conclusion that the oxidation process was initiated from the very first moment of irradiation, and it produced ketones, acids, esters (intramolecular and of acetate type), peracids, peresters, hydroperoxides, and alcohols. The molecular weight values and gel number values, which were established as well, pointed out that oxidation was accompanied by cracking of polymer macromolecules, and also by polymer crosslinking to a limited degree. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012.

Nowicki J.,Institute of Heavy Organic Synthesis | Luczak J.,Technical University of Gdansk | Stanczyk D.,Institute of Heavy Organic Synthesis
RSC Advances | Year: 2016

A series of amphiphilic 1-alkyl-3-methylimidazolium hydrogen sulfate ionic liquids were synthesized. Acidic hydrogen sulfate ionic liquids with the alkyl chains C6-C14 are characterized by good surface properties. Their surface properties (adsorption and micellization parameters, degree of ionization of micelles, Krafft temperatures and thermodynamic parameters) were determined. Synthesized ionic liquids were applied as a co-catalyst in an oxirane ring opening reaction in epoxidized fatty acid methyl esters (FAME). Their co-catalytic activities were determined and discussed as a function of their structure and surface properties. It was found that the co-catalytic properties, both conversion and selectivity, of alkylimidazolium hydrogen sulfate ionic liquids noticeably depended on the alkyl chain lengths, and in consequence their properties. © 2016 The Royal Society of Chemistry.

The purpose of the work is to present a simple test method for assessment of the susceptibility of thermoplastics to reactions under dynamic conditions. It is based on measurements of torque values with the use of a batch mixer. It is well-known that the torque values are strictly related to polymer melt viscosity. On the other hand, temperature changes in the batch mixer due to friction and thermal effects of chemical reactions are restrictions precluding measurements in isothermal conditions. However, it was established that the temperature spontaneously changing in a chamber of the batch mixer may be seen as the opportunity to evaluate the changes of torque induced by chemical processes. For radical modification of eleven ethylene copolymers, it was shown that results obtained according to the method provide valuable information for insight into changes taking place in the reacting system. © 2015 Elsevier Ltd.

Jasinski R.,Cracov University of Technology | Dresler E.,Institute of Heavy Organic Synthesis
Phosphorus, Sulfur and Silicon and the Related Elements | Year: 2016

DFT calculations at different levels indicate a one-step nonpolar mechanism of the thermal decomposition of isomeric 2,5-dinitro-3,4-dimethyl-thiolene 1,1-dioxides. Formally, this process can be equivalent to retro [4+1]-cycloaddition reaction. © 2016 Taylor & Francis Group, LLC.

Nowicki J.,Institute of Heavy Organic Synthesis | Sokolowski A.,Wroclaw University of Technology | Reksa D.,Wroclaw University of Technology
Tenside, Surfactants, Detergents | Year: 2011

This paper presents the results from the research on the synthesis of new perfluorinated carbohydrate surfactants. Surface active properties were studied for new surfactants and their wettability was evaluated on selected solid surfaces. © Carl Hanser Publisher, Munich.

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