Time filter

Source Type

Kędzierzyn-Koźle, Poland

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.

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.

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.

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.

Discover hidden collaborations