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Slovenj Gradec, Slovenia

Liska R.,Polymer Technology College | Liska R.,Vienna University of Technology | Russmuller G.,Medical University of Vienna | Kotek J.,Czech Institute of Macromolecular Chemical | Krajnc P.,University of Maribor
Macromolecular Bioscience | Year: 2015

Open porous microcellular polymers with high degrees of porosity are prepared from divinyl adipate and pentaerythritol tetrakis(3-mercaptopropionate) by thiol-ene polymerization within high internal phase emulsions. The influence of monomer ratio, droplet phase volume, and emulsion stirring rate on the morphology and mechanical properties of the products is studied. The newly produced material is successfully applied as a scaffold for osteoblastic MC3T3-E1 cells in vitro, showing increased rates of cell growth compared to material prepared by standard methods. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Pulko I.,Polymer Technology College | Krajnc P.,University of Maribor
Macromolecular Rapid Communications | Year: 2012

Recently, a series of new monomers and polymerization mechanisms has been applied to the templating of high internal phase emulsions (HIPEs) providing a route to hierarchically porous materials with a range of functionalities and applications. The high degree of control over the pore size is another attractive feature of these materials. Usually, the continuous phase contains monomers, the droplet phase is used to template the large, primary pores, which are interconnected by secondary pores. The addition of nonpolymerizable components to the continuous phase can result in phase separation during polymerization and tertiary pores. Applications include polymer supports for catalysis and synthesis, separation and filtration, cell culture media, enzyme supports, and structural and isolation applications. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Perse L.S.,Slovenian National Institute of Chemistry | Perse L.S.,Polymer Technology College | Huskic M.,Slovenian National Institute of Chemistry
European Polymer Journal | Year: 2016

Detailed rheological characterization has been performed for star-shaped graft copolymers, prepared from polycaprolactone (PCL) and hyperbranched polyester Boltorn H40 (BH40). As the reactant ratio increased from BH40:PCL = 1:1 to 1:10 the molar mass of the copolymer increased as well. Flow behavior has been determined under destructive shear conditions for the polymer melts at 75°C, at which Cox-Merz rule has been applied for all the copolymers used. The results show that the addition of PCL to BH40 decreases the viscosity of copolymer with increasing molar mass, but only to the ratio BH40 vs. PCL = 1:4. Above that ratio a slight increase in viscosity is observed for the ratio 1:5, while viscosity significantly increases for the copolymer with the highest reactant ratio. Temperature dependence of viscoelastic properties has been performed in linear viscoelastic range at cooling/heating rate of 10°C min-1. The results strongly coincides with the results of DSC measurements, moreover, the combination of rheological and thermal characterization provides a deeper insight into structural changes during cooling/heating process. © 2016 Elsevier Ltd. All rights reserved. Source

Anzlovar A.,Slovenian National Institute of Chemistry | Kogej K.,University of Ljubljana | Orel Z.C.,Slovenian National Institute of Chemistry | Zigon M.,Slovenian National Institute of Chemistry | Zigon M.,Polymer Technology College
Crystal Growth and Design | Year: 2014

ZnO nanoparticles (NPs) were synthesized by a seeded polyol process in di(ethylene glycol) (DEG) using zinc acetate as a precursor in the presence of inorganic hydroxides (NaOH, KOH, LiOH). The precursor was transformed into ZnO in DEG without solid intermediates as shown by Fourier transform infrared spectroscopy. Both Raman and photoluminescence spectroscopies confirmed the presence of defects in the ZnO crystal structure which generated visible light emission when excited with UV light. The molar ratio of seeds/precursor affects ZnO particle growth, and at a high ratio (10/1) growth of ZnO NPs is practically prevented, giving ZnO with a narrow particle size distribution. By decreasing the precursor concentration from 1.0 to 0.01 M, ZnO particle size decreased from 50-200 nm to 20-60 nm; however, the degree of agglomeration was increased. Type of cation plays only a minor role in the ZnO NPs formation. By increasing the hydroxide/precursor molar ratio from 1/1 to 5/1, the ZnO particle size is reduced from 50-200 nm to 20-40 nm. Therefore, the hydroxide/precursor molar ratio has a significant role in the formation of ZnO because it defines the concentration of OH- ions, which is the key factor in this process. © 2014 American Chemical Society. Source

Tasic B.,University of Ljubljana | Mrzel A.,Jozef Stefan Institute | Huskic M.,Slovenian National Institute of Chemistry | Huskic M.,Polymer Technology College | And 3 more authors.
Journal of Physical Chemistry C | Year: 2014

We investigated the orientational distribution of MoS2 nanotubes incorporated into a commercial photoreactive liquid-crystalline medium. Electron microscopy imaging and Raman spectroscopy measurements show that interaction with the liquid-crystalline host induces strong directional alignment of the nanotubes. The obtained alignment is "frozen" into the structure by subsequent photopolymerization reaction, which on one hand prevents agglomeration and on the other hand produces a solid composite film with controlled orientation of the nanotubes. Analysis of the mechanical properties shows that by addition of 0.1 wt % nanotubes the elastic modulus of the films is increased by 35%. Our results demonstrate that the nanotube alignment approach based on photopolymerizable liquid-crystalline media, which is relatively inefficient for carbon nanotubes, might be much more promising for inorganic nanotubes. © 2014 American Chemical Society. Source

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