Polymer Technology College

Slovenj Gradec, Slovenia

Polymer Technology College

Slovenj Gradec, Slovenia
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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.

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.

Huskic M.,Slovenian National Institute of Chemistry | Huskic M.,Polymer Technology College | Pulko I.,Polymer Technology College
European Polymer Journal | Year: 2015

Simple and efficient method for the synthesis of multiarm star-shaped graft copolymers of polycaprolactone (PCL) and hyperbranched polyester Boltorn H40 (BH40) is presented. Grafting of ε-caprolactone (CL) from BH40 proceeds without the addition of a catalyst, and without drying of CL. p-Toluenesulfonic acid, which is added as a catalyst during the synthesis of BH40, acts also as a catalyst for CL grafting. Terminal -OH groups of BH40 react with CL, while the linear ones remain almost intact, except at high reactant ratio and prolonged reaction time. The presence of water changes the copolymer structure and properties, but the influence is minor. Star-shaped copolymers were prepared in a mass ratio of BH40:CL 1:1 to 1:10 and characterized. Glass transition temperature is decreasing while the degree of crystallinity is increasing with the increasing reactant ratio. © 2015 Elsevier Ltd. All rights reserved.

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.

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.

Pulko I.,Polymer Technology College | Smrekar V.,BIA Separations d.o.o. | Podgornik A.,BIA Separations d.o.o. | Krajnc P.,University of Maribor
Journal of Chromatography A | Year: 2011

Approximately 25. cm × 25. cm large sheets of crosslinked highly porous poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate-co-ethylhexyl methacrylate) membranes with an average thicknesses between 285 and 565 μm were prepared by casting a high internal phase emulsion (HIPE) containing monomers onto glass substrates and subsequent polymerisation. Open cellular porous polyHIPE type membranes were obtained with large pores (cavity) sizes between 3 and 10 μm while interconnecting pores were between 1 and 3 μm. The percentage of ethylhexyl acrylate and ethyleneglycol dimethacrylate influenced the flexibility and morphology of the resulting membranes. Porous membranes were chemically modified with diethylamine to yield functionalised supports for ion exchange chromatography. Cylindrical housings were used for positioning of the membranes and allowing flow of the mobile phase. Pulse experiments were used to study the flow characteristics and a homogeneous flow through the entire area of the membrane was found. Bovine serum albumin was purified by a 8. ml column containing functional membrane in modular shape; dynamic binding capacity was measured to be as high as 45. mg/ml. © 2010 Elsevier B.V.

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.

Hus S.,Polymer Technology College | Hus S.,University of Maribor | Hus S.,ALBA Recycling GmbH R and D Laboratory | Kolar M.,University of Maribor | Krajnc P.,University of Maribor
Journal of Chromatography A | Year: 2016

Removal of silver, lead and cadmium ions from both model solutions and real contaminated water was achieved, in a flow through manner, by using highly porous functionalized poly(glycidyl methacrylate) materials, prepared by the polymerisation of high internal phase emulsions (polyHIPE), with significant sorption differences between metals allowing for selective removal. PolyHIPEs, initially prepared from glycidyl methacrylate as a functional monomer, were functionalized with pentaerythritol tetrakis(3-mercaptopropionate), 1,9-nonanedithiol and 2-aminobenzenethiol via the epoxy ring opening on the polymer supports and applied in a flow-through manner via encasements into dedicated disk holders. Capacity of 21.7 mg Ag per gram of polymer was found for 1,9-nonanedithiol functionalized polymers, while the capacity was decreasing with the decreasing ionic radius of the metal; the dynamics of sorption also depended on metal ion size and furthermore on the thiol used for the polymer functionalization. © 2016 Elsevier B.V.

Pulko I.,University of Maribor | Pulko I.,Polymer Technology College | Wall J.,Durham University | Krajnc P.,University of Maribor | Cameron N.R.,Durham University
Chemistry - A European Journal | Year: 2010

The action is at the surface: Ultra-high surface area emulsion templated porous polymers are prepared by the hypercrosslinking method. Control of the extent of conversion of benzyl chloride groups leaves residual accessible functionality for subsequent immobilisation of 4- (N-methylamino)pyridine, giving a highly efficient nucleophilic catalyst that outperforms both unhypercrosslinked versions and hypercrosslinked polymer beads. © 2010 Wiley-VCH Verlag.GmbH&Co. KGaA, Weinheim.

Hus S.,Polymer Technology College | Krajnc P.,University of Maribor
Polymer (United Kingdom) | Year: 2014

Highly porous monoliths with excellent mechanical properties and porosity of up to 90% were prepared by the polymerisation of high internal phase emulsions (HIPE) containing methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA). Materials with open cellular morphology and cavity diameters between 0.6 and 4.5 μm are obtained using a homogenizer and between 0.8 and 25 μm using a standard overhead stirrer. Samples with 80% pore volume have E-moduli up to 180 MPa, while 75% porous samples exhibit E-moduli up to 211 MPa. A dependence of mechanical properties on cavity size distribution is identified, where a more hierarchically developed porous structure results in significantly better mechanical properties. © 2014 Elsevier Ltd. All rights reserved.

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