TY  - JOUR
AU  - Tomić, Milos
AU  - Dunjić, Branko
AU  - Nikolić, Marija S.
AU  - Trifković, Kata
AU  - Stanković, Nadezda
AU  - Pavlović, Vladimir
AU  - Bajat, Jelena
AU  - Djonlagić, Jasna
PY  - 2019
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/5068
AB  - In the present study the commercial multifunctional fatty acid polyamidoamine (PAA) was for the first time simultaneously applied as a curing agent and clay modifier for epoxy/clay nanocomposites (NC) based on diglycidyl ether of bisphenol A. The montmorillonite (Cloisite (R) Na+) was modified with different quantities of partially and fully protonated polyamidoamine. The NCs with 0.5 wt% novel organoclay were prepared by solution intercalation method. The major aims of this paper are investigations of the effects of the composition of PAA modified clays on structure, mechanical, barrier properties and corrosion stability on steel substrates of NCs were studied. The thermogravimetric, flame photometry and X-ray diffraction analyses confirmed the efficient modification of clay surface with polyamidoamine, predominantly located within layers. The NCs exhibited an intercalated/exfoliated morphology and the presence of free amino groups and increased content of modifier facilitated dispersion of clay particles within the polymer matrix, as shown by electron microscopy techniques (SEM, TEM). Under an optimized loading of PAA (molar quantity of total amino groups per clay cation exchange capacity of 1.75), the layers in stacks were separated by 5.0 nm and high number of individual layers was present in NC. Clay modified by PAA with free amino groups showed increased storage modulus in the rubbery state, glass transition temperature of NCs, while dumping factor was decreased. The tensile test confirmed that introduction of flexible modifier on the epoxy/clay interface lead to increase in the ultimate tensile strenght and elongation at break by 31% and toughness up to 83%. The electrochemical impedance spectroscopy and permeability tests proved the pronounced barrier effect of clay particles against corrosive species and water vapor when high dispersion degree of clay in NC was achieved.
PB  - Elsevier Science Sa, Lausanne
T2  - Progress in Organic Coatings
T1  - Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites
EP  - 321
SP  - 311
VL  - 131
DO  - 10.1016/j.porgcoat.2019.02.037
ER  - 

@article{
author = "Tomić, Milos and Dunjić, Branko and Nikolić, Marija S. and Trifković, Kata and Stanković, Nadezda and Pavlović, Vladimir and Bajat, Jelena and Djonlagić, Jasna",
year = "2019",
abstract = "In the present study the commercial multifunctional fatty acid polyamidoamine (PAA) was for the first time simultaneously applied as a curing agent and clay modifier for epoxy/clay nanocomposites (NC) based on diglycidyl ether of bisphenol A. The montmorillonite (Cloisite (R) Na+) was modified with different quantities of partially and fully protonated polyamidoamine. The NCs with 0.5 wt% novel organoclay were prepared by solution intercalation method. The major aims of this paper are investigations of the effects of the composition of PAA modified clays on structure, mechanical, barrier properties and corrosion stability on steel substrates of NCs were studied. The thermogravimetric, flame photometry and X-ray diffraction analyses confirmed the efficient modification of clay surface with polyamidoamine, predominantly located within layers. The NCs exhibited an intercalated/exfoliated morphology and the presence of free amino groups and increased content of modifier facilitated dispersion of clay particles within the polymer matrix, as shown by electron microscopy techniques (SEM, TEM). Under an optimized loading of PAA (molar quantity of total amino groups per clay cation exchange capacity of 1.75), the layers in stacks were separated by 5.0 nm and high number of individual layers was present in NC. Clay modified by PAA with free amino groups showed increased storage modulus in the rubbery state, glass transition temperature of NCs, while dumping factor was decreased. The tensile test confirmed that introduction of flexible modifier on the epoxy/clay interface lead to increase in the ultimate tensile strenght and elongation at break by 31% and toughness up to 83%. The electrochemical impedance spectroscopy and permeability tests proved the pronounced barrier effect of clay particles against corrosive species and water vapor when high dispersion degree of clay in NC was achieved.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Progress in Organic Coatings",
title = "Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites",
pages = "321-311",
volume = "131",
doi = "10.1016/j.porgcoat.2019.02.037"
}

Tomić, M., Dunjić, B., Nikolić, M. S., Trifković, K., Stanković, N., Pavlović, V., Bajat, J.,& Djonlagić, J.. (2019). Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites. in Progress in Organic Coatings
Elsevier Science Sa, Lausanne., 131, 311-321.
https://doi.org/10.1016/j.porgcoat.2019.02.037

Tomić M, Dunjić B, Nikolić MS, Trifković K, Stanković N, Pavlović V, Bajat J, Djonlagić J. Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites. in Progress in Organic Coatings. 2019;131:311-321.
doi:10.1016/j.porgcoat.2019.02.037 .

Tomić, Milos, Dunjić, Branko, Nikolić, Marija S., Trifković, Kata, Stanković, Nadezda, Pavlović, Vladimir, Bajat, Jelena, Djonlagić, Jasna, "Polyamidoamine as a clay modifier and curing agent in preparation of epoxy nanocomposites" in Progress in Organic Coatings, 131 (2019):311-321,
https://doi.org/10.1016/j.porgcoat.2019.02.037 . .

TY  - JOUR
AU  - Rusmirović, Jelena D.
AU  - Rancić, Milica P.
AU  - Pavlović, Vladimir
AU  - Rakić, Vesna
AU  - Stevanović, Sanja
AU  - Djonlagić, Jasna
AU  - Marinković, Aleksandar D.
PY  - 2018
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/4652
AB  - Unsaturated fatty acid (FA)-modified nanocellulose (m-NC) shows potential application in improving mechanical properties of unsaturated polyester/m-NC nanocomposites (UPe/m-NC). A polyester matrix is obtained by polycondensation of maleic anhydride and products of poly(ethylene terephthalate) depolymerization with propylene glycol. Two methods of NC modification are performed: direct esterification with oleic acid, linseed, or sunflower oil FAs, and esterification/amidation with maleic acid/ethylene diamine (MA/EDA) bridging group followed by amidation with methyl ester of FAs. Increases of stress at break in the ranges from 148.8% to 181.4% and from 155.8% to193.0% for UPe/m-NC composites loaded with 1 wt% of NC modified directly or via MA/EDA cross-linker, respectively, are obtained. Results of the modeling of tensile modulus, by using the Cox-Krenchel model, show good agreement with experimentally obtained data. The effect of FAs' cross-linking capabilities on the dynamic-mechanical and thermal properties of the UPe/m-NC is studied. Cross-linking density, modulus, and T-g of the nanocomposite show appropriate relation with the unsaturation extent/structure of NC modification.
PB  - Wiley-V C H Verlag Gmbh, Weinheim
T2  - Macromolecular Materials and Engineering
T1  - Cross-Linkable Modified Nanocellulose/Polyester Resin-Based Composites: Effect of Unsaturated Fatty Acid Nanocellulose Modification on Material Performances
IS  - 8
VL  - 303
DO  - 10.1002/mame.201700648
ER  - 

@article{
author = "Rusmirović, Jelena D. and Rancić, Milica P. and Pavlović, Vladimir and Rakić, Vesna and Stevanović, Sanja and Djonlagić, Jasna and Marinković, Aleksandar D.",
year = "2018",
abstract = "Unsaturated fatty acid (FA)-modified nanocellulose (m-NC) shows potential application in improving mechanical properties of unsaturated polyester/m-NC nanocomposites (UPe/m-NC). A polyester matrix is obtained by polycondensation of maleic anhydride and products of poly(ethylene terephthalate) depolymerization with propylene glycol. Two methods of NC modification are performed: direct esterification with oleic acid, linseed, or sunflower oil FAs, and esterification/amidation with maleic acid/ethylene diamine (MA/EDA) bridging group followed by amidation with methyl ester of FAs. Increases of stress at break in the ranges from 148.8% to 181.4% and from 155.8% to193.0% for UPe/m-NC composites loaded with 1 wt% of NC modified directly or via MA/EDA cross-linker, respectively, are obtained. Results of the modeling of tensile modulus, by using the Cox-Krenchel model, show good agreement with experimentally obtained data. The effect of FAs' cross-linking capabilities on the dynamic-mechanical and thermal properties of the UPe/m-NC is studied. Cross-linking density, modulus, and T-g of the nanocomposite show appropriate relation with the unsaturation extent/structure of NC modification.",
publisher = "Wiley-V C H Verlag Gmbh, Weinheim",
journal = "Macromolecular Materials and Engineering",
title = "Cross-Linkable Modified Nanocellulose/Polyester Resin-Based Composites: Effect of Unsaturated Fatty Acid Nanocellulose Modification on Material Performances",
number = "8",
volume = "303",
doi = "10.1002/mame.201700648"
}

Rusmirović, J. D., Rancić, M. P., Pavlović, V., Rakić, V., Stevanović, S., Djonlagić, J.,& Marinković, A. D.. (2018). Cross-Linkable Modified Nanocellulose/Polyester Resin-Based Composites: Effect of Unsaturated Fatty Acid Nanocellulose Modification on Material Performances. in Macromolecular Materials and Engineering
Wiley-V C H Verlag Gmbh, Weinheim., 303(8).
https://doi.org/10.1002/mame.201700648

Rusmirović JD, Rancić MP, Pavlović V, Rakić V, Stevanović S, Djonlagić J, Marinković AD. Cross-Linkable Modified Nanocellulose/Polyester Resin-Based Composites: Effect of Unsaturated Fatty Acid Nanocellulose Modification on Material Performances. in Macromolecular Materials and Engineering. 2018;303(8).
doi:10.1002/mame.201700648 .

Rusmirović, Jelena D., Rancić, Milica P., Pavlović, Vladimir, Rakić, Vesna, Stevanović, Sanja, Djonlagić, Jasna, Marinković, Aleksandar D., "Cross-Linkable Modified Nanocellulose/Polyester Resin-Based Composites: Effect of Unsaturated Fatty Acid Nanocellulose Modification on Material Performances" in Macromolecular Materials and Engineering, 303, no. 8 (2018),
https://doi.org/10.1002/mame.201700648 . .

TY  - JOUR
AU  - Pavlićević, Milica Ž.
AU  - Tomić, Milos D.
AU  - Djonlagić, Jasna
AU  - Stanojević, Sladjana
AU  - Vučelić-Radović, Biljana
PY  - 2018
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/4747
AB  - The effects of subunit composition of two major proteins of soybean: glycinin (11S) and -conglycinin (7S) in nine different genotypes, on solubility and emulsifying and gelling properties at different pH (3, 5, 6, and 8) were examined. High-protein genotypes (more than 40%) contained low amounts of the subunit. The main factors influencing solubility at pH 6 were the content of , (r = 0.89 and r = 0.91 at P  lt  0.05, respectively) and subunit contents (r = -0.71 at P  lt  0.05) of -conglycinin, while at pH 3 acidic subunits in glycinin had a positive correlation with solubility (r = 0.69 at P  lt  0.05). Emulsion activity at pH 6 was higher for genotypes synthesizing subunit (r = 0.57 at P  lt  0.05). Genotypes synthesizing higher amounts of and subunit had higher emulsion stability at pH 6 (r = 0.85 and r = 0.92 at P  lt  0.05, respectively) and pH 8 (r = 0.91 and r = 0.97 at P  lt  0.05, respectively). The rheological measurements showed that genotypes with 11S/7S ratio higher than 2.2 formed gels with enhanced storage moduli. This influence was largely due to the high content of SH groups in glycinin acidic polypeptides resulting in stabilization of gels via disulfide bonding. Gels prepared from genotypes containing higher amounts of subunit of -conglycinin exhibited reduced elastic properties. Genotypes showing better solubility also had higher emulsion stability, but formed weaker gels and had lower emulsion activity near neutral pH.
PB  - Wiley, Hoboken
T2  - Journal of the American Oil Chemists Society
T1  - Evaluation of Variation in Protein Composition on Solubility, Emulsifying and Gelling Properties of Soybean Genotypes Synthesizing ' Subunit
EP  - 134
IS  - 2
SP  - 123
VL  - 95
DO  - 10.1002/aocs.12002
ER  - 

@article{
author = "Pavlićević, Milica Ž. and Tomić, Milos D. and Djonlagić, Jasna and Stanojević, Sladjana and Vučelić-Radović, Biljana",
year = "2018",
abstract = "The effects of subunit composition of two major proteins of soybean: glycinin (11S) and -conglycinin (7S) in nine different genotypes, on solubility and emulsifying and gelling properties at different pH (3, 5, 6, and 8) were examined. High-protein genotypes (more than 40%) contained low amounts of the subunit. The main factors influencing solubility at pH 6 were the content of , (r = 0.89 and r = 0.91 at P  lt  0.05, respectively) and subunit contents (r = -0.71 at P  lt  0.05) of -conglycinin, while at pH 3 acidic subunits in glycinin had a positive correlation with solubility (r = 0.69 at P  lt  0.05). Emulsion activity at pH 6 was higher for genotypes synthesizing subunit (r = 0.57 at P  lt  0.05). Genotypes synthesizing higher amounts of and subunit had higher emulsion stability at pH 6 (r = 0.85 and r = 0.92 at P  lt  0.05, respectively) and pH 8 (r = 0.91 and r = 0.97 at P  lt  0.05, respectively). The rheological measurements showed that genotypes with 11S/7S ratio higher than 2.2 formed gels with enhanced storage moduli. This influence was largely due to the high content of SH groups in glycinin acidic polypeptides resulting in stabilization of gels via disulfide bonding. Gels prepared from genotypes containing higher amounts of subunit of -conglycinin exhibited reduced elastic properties. Genotypes showing better solubility also had higher emulsion stability, but formed weaker gels and had lower emulsion activity near neutral pH.",
publisher = "Wiley, Hoboken",
journal = "Journal of the American Oil Chemists Society",
title = "Evaluation of Variation in Protein Composition on Solubility, Emulsifying and Gelling Properties of Soybean Genotypes Synthesizing ' Subunit",
pages = "134-123",
number = "2",
volume = "95",
doi = "10.1002/aocs.12002"
}

Pavlićević, M. Ž., Tomić, M. D., Djonlagić, J., Stanojević, S.,& Vučelić-Radović, B.. (2018). Evaluation of Variation in Protein Composition on Solubility, Emulsifying and Gelling Properties of Soybean Genotypes Synthesizing ' Subunit. in Journal of the American Oil Chemists Society
Wiley, Hoboken., 95(2), 123-134.
https://doi.org/10.1002/aocs.12002

Pavlićević MŽ, Tomić MD, Djonlagić J, Stanojević S, Vučelić-Radović B. Evaluation of Variation in Protein Composition on Solubility, Emulsifying and Gelling Properties of Soybean Genotypes Synthesizing ' Subunit. in Journal of the American Oil Chemists Society. 2018;95(2):123-134.
doi:10.1002/aocs.12002 .

Pavlićević, Milica Ž., Tomić, Milos D., Djonlagić, Jasna, Stanojević, Sladjana, Vučelić-Radović, Biljana, "Evaluation of Variation in Protein Composition on Solubility, Emulsifying and Gelling Properties of Soybean Genotypes Synthesizing ' Subunit" in Journal of the American Oil Chemists Society, 95, no. 2 (2018):123-134,
https://doi.org/10.1002/aocs.12002 . .

TY  - JOUR
AU  - Tomić, Milog
AU  - Dunjić, Branko
AU  - Nikolić, Marija S.
AU  - Maletaskić, Jelena
AU  - Pavlović, Vladimir
AU  - Bajat, Jelena
AU  - Djonlagić, Jasna
PY  - 2018
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/4750
AB  - The major aims of this paper are the investigation of the effects of the mixing procedure and the montmorillonite (Mt) surface modification on the structure (optical microscopy, XRD, TEM, SEM), rheological, mechanical properties (DMA, tensile test) and corrosion stability (electrochemical impedance spectroscopy) of clay mineral/epoxy nanocomposite (CPN). Two series of CPN samples were prepared based on diglycidyl ether of bisphenol A (DGEBA) and polyamidoamine curing agent with three organophilic Mt and sodium-montmorillonite (1 wt%). Mt were mixed with DGEBA solution in the powder (direct mixing) and in the form of dispersions, preswollen in a commercial coating thinner (solution intercalation). The commercial Mt (Cloisite 30B) modified by quaternary alkylammonium ions bearing hydroxyl groups and especially Mt functionalized by primary (HDA(+)-Mt) alkylammonium ions, at loadings close to cation exchange capacity (CRC), were significantly swollen by thinner and further uniformly dispersed into CPN. Meanwhile, low gel volumes in thinner were found for more hydrophobic Mt (Cloisite 15A). The compatibility of Mt with solvents was well described by solubility and Flory-Huggins interaction parameters. In contrast to the direct incorporation of Mt powders in CPN, swelling enhanced intercalation of epoxy matrix into Mt, and for HDA(+)-Mt based CPN interlayer spacing reached 4.4 nm. The usage of HDA(+)-Mt organoclay and solution intercalation procedure provided the highest enhancement in rheological parameters (G', G", of Mt/epoxy dispersions and glassy storage modulus, Young's modulus and barrier properties of cured CPN.
PB  - Elsevier Science Bv, Amsterdam
T2  - Applied Clay Science
T1  - Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods
EP  - 63
SP  - 52
VL  - 154
DO  - 10.1016/j.clay.2017.12.047
ER  - 

@article{
author = "Tomić, Milog and Dunjić, Branko and Nikolić, Marija S. and Maletaskić, Jelena and Pavlović, Vladimir and Bajat, Jelena and Djonlagić, Jasna",
year = "2018",
abstract = "The major aims of this paper are the investigation of the effects of the mixing procedure and the montmorillonite (Mt) surface modification on the structure (optical microscopy, XRD, TEM, SEM), rheological, mechanical properties (DMA, tensile test) and corrosion stability (electrochemical impedance spectroscopy) of clay mineral/epoxy nanocomposite (CPN). Two series of CPN samples were prepared based on diglycidyl ether of bisphenol A (DGEBA) and polyamidoamine curing agent with three organophilic Mt and sodium-montmorillonite (1 wt%). Mt were mixed with DGEBA solution in the powder (direct mixing) and in the form of dispersions, preswollen in a commercial coating thinner (solution intercalation). The commercial Mt (Cloisite 30B) modified by quaternary alkylammonium ions bearing hydroxyl groups and especially Mt functionalized by primary (HDA(+)-Mt) alkylammonium ions, at loadings close to cation exchange capacity (CRC), were significantly swollen by thinner and further uniformly dispersed into CPN. Meanwhile, low gel volumes in thinner were found for more hydrophobic Mt (Cloisite 15A). The compatibility of Mt with solvents was well described by solubility and Flory-Huggins interaction parameters. In contrast to the direct incorporation of Mt powders in CPN, swelling enhanced intercalation of epoxy matrix into Mt, and for HDA(+)-Mt based CPN interlayer spacing reached 4.4 nm. The usage of HDA(+)-Mt organoclay and solution intercalation procedure provided the highest enhancement in rheological parameters (G', G", of Mt/epoxy dispersions and glassy storage modulus, Young's modulus and barrier properties of cured CPN.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Applied Clay Science",
title = "Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods",
pages = "63-52",
volume = "154",
doi = "10.1016/j.clay.2017.12.047"
}

Tomić, M., Dunjić, B., Nikolić, M. S., Maletaskić, J., Pavlović, V., Bajat, J.,& Djonlagić, J.. (2018). Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods. in Applied Clay Science
Elsevier Science Bv, Amsterdam., 154, 52-63.
https://doi.org/10.1016/j.clay.2017.12.047

Tomić M, Dunjić B, Nikolić MS, Maletaskić J, Pavlović V, Bajat J, Djonlagić J. Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods. in Applied Clay Science. 2018;154:52-63.
doi:10.1016/j.clay.2017.12.047 .

Tomić, Milog, Dunjić, Branko, Nikolić, Marija S., Maletaskić, Jelena, Pavlović, Vladimir, Bajat, Jelena, Djonlagić, Jasna, "Dispersion efficiency of montmorillonites in epoxy nanocomposites using solution intercalation and direct mixing methods" in Applied Clay Science, 154 (2018):52-63,
https://doi.org/10.1016/j.clay.2017.12.047 . .

TY  - JOUR
AU  - Stefanović, Ivan S.
AU  - Djonlagić, Jasna
AU  - Tovilović, Gordana
AU  - Nestorov, Jelena
AU  - Antić, Vesna
AU  - Ostojić, Sanja
AU  - Pergal, Marija V.
PY  - 2015
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3799
AB  - Polyurethane copolymers based on ,-dihydroxypropyl poly(dimethylsiloxane) (PDMS) with a range of soft segment contents were prepared by two-stage polymerization, and their microstructures, thermal, thermomechanical, and surface properties, as well as in vitro hemo- and cytocompatibility were evaluated. All utilized characterization methods confirmed the existence of moderately microphase separated structures with the appearance of some microphase mixing between segments as the PDMS (i.e., soft segment) content increased. Copolymers showed higher crystallinity, storage moduli, surface roughness, and surface free energy, but less hydrophobicity with decreasing PDMS content. Biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact, an extraction method and after pretreatment of copolymers with multicomponent protein mixture, as well as by a competitive protein adsorption assay. Copolymers showed no toxic effect to endothelial cells and all copolymers, except that with the lowest PDMS content, exhibited resistance to endothelial cell adhesion, suggesting their unsuitability for long-term biomedical devices which particularly require re-endothelialization. All copolymers exhibited excellent resistance to fibrinogen adsorption and adsorbed more albumin than fibrinogen in the competitive adsorption assay, suggesting their good hemocompatibility. The noncytotoxic chemistry of these synthesized materials, combined with their nonadherent properties which are inhospitable to cell attachment and growth, underlie the need for further investigations to clarify their potential for use in short-term biomedical devices.
PB  - Wiley-Blackwell, Hoboken
T2  - Journal of Biomedical Materials Research Part A
T1  - Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells
EP  - 1475
IS  - 4
SP  - 1459
VL  - 103
DO  - 10.1002/jbm.a.35285
ER  - 

@article{
author = "Stefanović, Ivan S. and Djonlagić, Jasna and Tovilović, Gordana and Nestorov, Jelena and Antić, Vesna and Ostojić, Sanja and Pergal, Marija V.",
year = "2015",
abstract = "Polyurethane copolymers based on ,-dihydroxypropyl poly(dimethylsiloxane) (PDMS) with a range of soft segment contents were prepared by two-stage polymerization, and their microstructures, thermal, thermomechanical, and surface properties, as well as in vitro hemo- and cytocompatibility were evaluated. All utilized characterization methods confirmed the existence of moderately microphase separated structures with the appearance of some microphase mixing between segments as the PDMS (i.e., soft segment) content increased. Copolymers showed higher crystallinity, storage moduli, surface roughness, and surface free energy, but less hydrophobicity with decreasing PDMS content. Biocompatibility of copolymers was evaluated using an endothelial EA.hy926 cell line by direct contact, an extraction method and after pretreatment of copolymers with multicomponent protein mixture, as well as by a competitive protein adsorption assay. Copolymers showed no toxic effect to endothelial cells and all copolymers, except that with the lowest PDMS content, exhibited resistance to endothelial cell adhesion, suggesting their unsuitability for long-term biomedical devices which particularly require re-endothelialization. All copolymers exhibited excellent resistance to fibrinogen adsorption and adsorbed more albumin than fibrinogen in the competitive adsorption assay, suggesting their good hemocompatibility. The noncytotoxic chemistry of these synthesized materials, combined with their nonadherent properties which are inhospitable to cell attachment and growth, underlie the need for further investigations to clarify their potential for use in short-term biomedical devices.",
publisher = "Wiley-Blackwell, Hoboken",
journal = "Journal of Biomedical Materials Research Part A",
title = "Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells",
pages = "1475-1459",
number = "4",
volume = "103",
doi = "10.1002/jbm.a.35285"
}

Stefanović, I. S., Djonlagić, J., Tovilović, G., Nestorov, J., Antić, V., Ostojić, S.,& Pergal, M. V.. (2015). Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells. in Journal of Biomedical Materials Research Part A
Wiley-Blackwell, Hoboken., 103(4), 1459-1475.
https://doi.org/10.1002/jbm.a.35285

Stefanović IS, Djonlagić J, Tovilović G, Nestorov J, Antić V, Ostojić S, Pergal MV. Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells. in Journal of Biomedical Materials Research Part A. 2015;103(4):1459-1475.
doi:10.1002/jbm.a.35285 .

Stefanović, Ivan S., Djonlagić, Jasna, Tovilović, Gordana, Nestorov, Jelena, Antić, Vesna, Ostojić, Sanja, Pergal, Marija V., "Poly(urethane-dimethylsiloxane) copolymers displaying a range of soft segment contents, noncytotoxic chemistry, and nonadherent properties toward endothelial cells" in Journal of Biomedical Materials Research Part A, 103, no. 4 (2015):1459-1475,
https://doi.org/10.1002/jbm.a.35285 . .

TY  - JOUR
AU  - Pergal, Marija V.
AU  - Stefanović, Ivan S.
AU  - Godjevac, Dejan
AU  - Antić, Vesna
AU  - Milacić, Vesna
AU  - Ostojić, Sanja
AU  - Rogan, Jelena
AU  - Djonlagić, Jasna
PY  - 2014
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3399
AB  - In this study, the synthesis, structure and physical properties of two series of thermoplastic polyurethanes based on hydroxypropyl-terminated poly(dimethylsiloxane) (HP-PDMS) or hydroxyethoxypropyl-terminated poly(dimethylsiloxane) (EO-PDMS) as soft segments, and 4,4'-methylenediphenyl diisocyanate and 1,4-butanediol as hard segments were investigated. The polyurethanes were synthesized by two-step polyaddition in solution. The effects of the type and content of PDMS segments on the structure, thermal and surface properties of copolymers were studied by H-1-, C-13-nuclear magnetic resonance (NMR) spectroscopy and two-dimensional NMR spectroscopies (heteronuclear multiple bond correlation (HMBC) and rotating-frame nuclear Overhauser effect (ROESY)), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide-angle X-ray scattering (WAXS), scanning electron microscopy (SEM) and water contact angle and water absorption measurements. Thermal properties investigated by DSC indicated that the presence of soft PDMS segments lowers the glass transition and melting temperatures of the hard phase as well as the degree of crystallinity. SEM analysis of the copolymers with a lower soft segment content confirmed the presence of spherulite superstructures, which arise from the crystallization of the hard segments. When compared with polyurethanes prepared from HP-PDMS, the copolymers synthesized from EO-PDMS with the same content of the soft segments had a higher degree of crystallinity, better thermal stability and a less hydrophobic surface. The obtained results showed that the synthesized polyurethanes had good thermal and surface properties, which could be further modified by changing the type or content of the soft segments.
PB  - Srpsko hemijsko društvo, Beograd
T2  - JOURNAL OF THE SERBIAN CHEMICAL SOCIETY
T1  - Structural, thermal and surface characterization of thermoplastic polyurethanes based on poly(dimethylsiloxane)
EP  - +
IS  - 7
SP  - 843
VL  - 79
DO  - 10.2298/JSC130819149P
ER  - 

@article{
author = "Pergal, Marija V. and Stefanović, Ivan S. and Godjevac, Dejan and Antić, Vesna and Milacić, Vesna and Ostojić, Sanja and Rogan, Jelena and Djonlagić, Jasna",
year = "2014",
abstract = "In this study, the synthesis, structure and physical properties of two series of thermoplastic polyurethanes based on hydroxypropyl-terminated poly(dimethylsiloxane) (HP-PDMS) or hydroxyethoxypropyl-terminated poly(dimethylsiloxane) (EO-PDMS) as soft segments, and 4,4'-methylenediphenyl diisocyanate and 1,4-butanediol as hard segments were investigated. The polyurethanes were synthesized by two-step polyaddition in solution. The effects of the type and content of PDMS segments on the structure, thermal and surface properties of copolymers were studied by H-1-, C-13-nuclear magnetic resonance (NMR) spectroscopy and two-dimensional NMR spectroscopies (heteronuclear multiple bond correlation (HMBC) and rotating-frame nuclear Overhauser effect (ROESY)), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), wide-angle X-ray scattering (WAXS), scanning electron microscopy (SEM) and water contact angle and water absorption measurements. Thermal properties investigated by DSC indicated that the presence of soft PDMS segments lowers the glass transition and melting temperatures of the hard phase as well as the degree of crystallinity. SEM analysis of the copolymers with a lower soft segment content confirmed the presence of spherulite superstructures, which arise from the crystallization of the hard segments. When compared with polyurethanes prepared from HP-PDMS, the copolymers synthesized from EO-PDMS with the same content of the soft segments had a higher degree of crystallinity, better thermal stability and a less hydrophobic surface. The obtained results showed that the synthesized polyurethanes had good thermal and surface properties, which could be further modified by changing the type or content of the soft segments.",
publisher = "Srpsko hemijsko društvo, Beograd",
journal = "JOURNAL OF THE SERBIAN CHEMICAL SOCIETY",
title = "Structural, thermal and surface characterization of thermoplastic polyurethanes based on poly(dimethylsiloxane)",
pages = "+-843",
number = "7",
volume = "79",
doi = "10.2298/JSC130819149P"
}

Pergal, M. V., Stefanović, I. S., Godjevac, D., Antić, V., Milacić, V., Ostojić, S., Rogan, J.,& Djonlagić, J.. (2014). Structural, thermal and surface characterization of thermoplastic polyurethanes based on poly(dimethylsiloxane). in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY
Srpsko hemijsko društvo, Beograd., 79(7), 843-+.
https://doi.org/10.2298/JSC130819149P

Pergal MV, Stefanović IS, Godjevac D, Antić V, Milacić V, Ostojić S, Rogan J, Djonlagić J. Structural, thermal and surface characterization of thermoplastic polyurethanes based on poly(dimethylsiloxane). in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY. 2014;79(7):843-+.
doi:10.2298/JSC130819149P .

Pergal, Marija V., Stefanović, Ivan S., Godjevac, Dejan, Antić, Vesna, Milacić, Vesna, Ostojić, Sanja, Rogan, Jelena, Djonlagić, Jasna, "Structural, thermal and surface characterization of thermoplastic polyurethanes based on poly(dimethylsiloxane)" in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY, 79, no. 7 (2014):843-+,
https://doi.org/10.2298/JSC130819149P . .

TY  - JOUR
AU  - Balaban, Milica
AU  - Antić, Vesna
AU  - Pergal, Marija V.
AU  - Godjevac, Dejan
AU  - Francolini, Iolanda
AU  - Martinelli, Andrea
AU  - Rogan, Jelena
AU  - Djonlagić, Jasna
PY  - 2013
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3294
AB  - Segmented poly(urethane-urea-siloxane)s (PUUS) were synthesized using 4,4'-methylenediphenyl diisocyanate (MDI) and ethylene diamine (ED) as the hard segment components and hydroxypropyl-terminated poly(dimethylsiloxane) (PDMS) as the soft segment component, where the hard segment content ranged from 38 to 65 wt%. Segmented PUUSs were prepared by a two-step polymerization procedure in tetrahydrofuran/N-methylpyrrolidone (THF/NMP) mixture with a large proportion of polar solvent. The structure, composition and hard segment length were determined by C-13 NMR and two-dimensional correlation spectroscopy. Thermal, mechanical, small-angle X-ray scattering and hydrogen bonding analyses indicated the formation of the microphase-separated copolymers with high tensile strength. Globular superstructures observed in the copolymer films by scanning electron microscopy (SEM) and atomic force microscopy (AFM) were probably arisen from the microstructural organization of the MDI-ED segments, depending on their content and length. The PUUS copolymers showed high water resistance and became more hydrophobic with increasing weight fraction of PDMS.
PB  - Springer, New York
T2  - Polymer Bulletin
T1  - Influence of the chemical structure of poly(urea-urethane-siloxane)s on their morphological, surface and thermal properties
EP  - 2518
IS  - 9
SP  - 2493
VL  - 70
DO  - 10.1007/s00289-013-0968-2
ER  - 

@article{
author = "Balaban, Milica and Antić, Vesna and Pergal, Marija V. and Godjevac, Dejan and Francolini, Iolanda and Martinelli, Andrea and Rogan, Jelena and Djonlagić, Jasna",
year = "2013",
abstract = "Segmented poly(urethane-urea-siloxane)s (PUUS) were synthesized using 4,4'-methylenediphenyl diisocyanate (MDI) and ethylene diamine (ED) as the hard segment components and hydroxypropyl-terminated poly(dimethylsiloxane) (PDMS) as the soft segment component, where the hard segment content ranged from 38 to 65 wt%. Segmented PUUSs were prepared by a two-step polymerization procedure in tetrahydrofuran/N-methylpyrrolidone (THF/NMP) mixture with a large proportion of polar solvent. The structure, composition and hard segment length were determined by C-13 NMR and two-dimensional correlation spectroscopy. Thermal, mechanical, small-angle X-ray scattering and hydrogen bonding analyses indicated the formation of the microphase-separated copolymers with high tensile strength. Globular superstructures observed in the copolymer films by scanning electron microscopy (SEM) and atomic force microscopy (AFM) were probably arisen from the microstructural organization of the MDI-ED segments, depending on their content and length. The PUUS copolymers showed high water resistance and became more hydrophobic with increasing weight fraction of PDMS.",
publisher = "Springer, New York",
journal = "Polymer Bulletin",
title = "Influence of the chemical structure of poly(urea-urethane-siloxane)s on their morphological, surface and thermal properties",
pages = "2518-2493",
number = "9",
volume = "70",
doi = "10.1007/s00289-013-0968-2"
}

Balaban, M., Antić, V., Pergal, M. V., Godjevac, D., Francolini, I., Martinelli, A., Rogan, J.,& Djonlagić, J.. (2013). Influence of the chemical structure of poly(urea-urethane-siloxane)s on their morphological, surface and thermal properties. in Polymer Bulletin
Springer, New York., 70(9), 2493-2518.
https://doi.org/10.1007/s00289-013-0968-2

Balaban M, Antić V, Pergal MV, Godjevac D, Francolini I, Martinelli A, Rogan J, Djonlagić J. Influence of the chemical structure of poly(urea-urethane-siloxane)s on their morphological, surface and thermal properties. in Polymer Bulletin. 2013;70(9):2493-2518.
doi:10.1007/s00289-013-0968-2 .

Balaban, Milica, Antić, Vesna, Pergal, Marija V., Godjevac, Dejan, Francolini, Iolanda, Martinelli, Andrea, Rogan, Jelena, Djonlagić, Jasna, "Influence of the chemical structure of poly(urea-urethane-siloxane)s on their morphological, surface and thermal properties" in Polymer Bulletin, 70, no. 9 (2013):2493-2518,
https://doi.org/10.1007/s00289-013-0968-2 . .

TY  - JOUR
AU  - Pergal, Marija V.
AU  - Antić, Vesna
AU  - Tovilović, Gordana
AU  - Nestorov, Jelena
AU  - Vasiljević-Radović, Dana
AU  - Djonlagić, Jasna
PY  - 2012
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2954
AB  - Novel polyurethane co-polymers (TPUs), based on poly(epsilon-caprolactone)-block-poly(dimethylsiloxane)-block-poly(epsilon-caprolactone) (PCL-PDMS-PCL) as soft segment and 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BD) as hard segment, were synthesized and evaluated for biomedical applications. The content of hard segments (HS) in the polymer chains was varied from 9 to 63 wt%. The influence of the content and length of the HS on the thermal, surface, mechanical properties and biocompatibility was investigated. The structure, composition and HS length were examined using H-1- and quantitative C-13-NMR spectroscopy. DSC results implied that the synthesized TPUs were semicrystalline polymers in which both the hard MDI/BD and soft PCL-PDMS-PCL segments participated. It was found that an increase in the average HS length (from 1.2 to 14.4 MDI/BD units) was accompanied by an increase in the crystallinity of the hard segments, storage moduli, hydrophilicity and degree of microphase separation of the co-polymers. Depending on the HS content, a gradual variation in surface properties of co-polymers was revealed by FTIR, AFM and static water contact angle measurements. The in vitro biocompatibility of co-polymers was evaluated using the endothelial EA. hy926 cell line and protein adsorption on the polyurethane films. All synthesized TPUs adsorbed more albumin than fibrinogen from multicomponent protein mixture, which may indicate biocompatibility. The polyurethane films with high HS content and/or high roughness coefficient exhibit good surface properties and biocompatible behavior, which was confirmed by non-toxic effects to cells and good cell adhesion. Therefore, the non-cytotoxic chemistry of the co-polymers makes them good candidates for further development as biomedical implants.
PB  - Taylor & Francis Ltd, Abingdon
T2  - Journal of Biomaterials Science-Polymer Edition
T1  - In Vitro Biocompatibility Evaluation of Novel Urethane-Siloxane Co-Polymers Based on Poly(epsilon-Caprolactone)-block-Poly(Dimethylsiloxane)-block-Poly(epsilon-Caprolactone)
EP  - 1657
IS  - 13
SP  - 1629
VL  - 23
DO  - 10.1163/092050611X589338
ER  - 

@article{
author = "Pergal, Marija V. and Antić, Vesna and Tovilović, Gordana and Nestorov, Jelena and Vasiljević-Radović, Dana and Djonlagić, Jasna",
year = "2012",
abstract = "Novel polyurethane co-polymers (TPUs), based on poly(epsilon-caprolactone)-block-poly(dimethylsiloxane)-block-poly(epsilon-caprolactone) (PCL-PDMS-PCL) as soft segment and 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BD) as hard segment, were synthesized and evaluated for biomedical applications. The content of hard segments (HS) in the polymer chains was varied from 9 to 63 wt%. The influence of the content and length of the HS on the thermal, surface, mechanical properties and biocompatibility was investigated. The structure, composition and HS length were examined using H-1- and quantitative C-13-NMR spectroscopy. DSC results implied that the synthesized TPUs were semicrystalline polymers in which both the hard MDI/BD and soft PCL-PDMS-PCL segments participated. It was found that an increase in the average HS length (from 1.2 to 14.4 MDI/BD units) was accompanied by an increase in the crystallinity of the hard segments, storage moduli, hydrophilicity and degree of microphase separation of the co-polymers. Depending on the HS content, a gradual variation in surface properties of co-polymers was revealed by FTIR, AFM and static water contact angle measurements. The in vitro biocompatibility of co-polymers was evaluated using the endothelial EA. hy926 cell line and protein adsorption on the polyurethane films. All synthesized TPUs adsorbed more albumin than fibrinogen from multicomponent protein mixture, which may indicate biocompatibility. The polyurethane films with high HS content and/or high roughness coefficient exhibit good surface properties and biocompatible behavior, which was confirmed by non-toxic effects to cells and good cell adhesion. Therefore, the non-cytotoxic chemistry of the co-polymers makes them good candidates for further development as biomedical implants.",
publisher = "Taylor & Francis Ltd, Abingdon",
journal = "Journal of Biomaterials Science-Polymer Edition",
title = "In Vitro Biocompatibility Evaluation of Novel Urethane-Siloxane Co-Polymers Based on Poly(epsilon-Caprolactone)-block-Poly(Dimethylsiloxane)-block-Poly(epsilon-Caprolactone)",
pages = "1657-1629",
number = "13",
volume = "23",
doi = "10.1163/092050611X589338"
}

Pergal, M. V., Antić, V., Tovilović, G., Nestorov, J., Vasiljević-Radović, D.,& Djonlagić, J.. (2012). In Vitro Biocompatibility Evaluation of Novel Urethane-Siloxane Co-Polymers Based on Poly(epsilon-Caprolactone)-block-Poly(Dimethylsiloxane)-block-Poly(epsilon-Caprolactone). in Journal of Biomaterials Science-Polymer Edition
Taylor & Francis Ltd, Abingdon., 23(13), 1629-1657.
https://doi.org/10.1163/092050611X589338

Pergal MV, Antić V, Tovilović G, Nestorov J, Vasiljević-Radović D, Djonlagić J. In Vitro Biocompatibility Evaluation of Novel Urethane-Siloxane Co-Polymers Based on Poly(epsilon-Caprolactone)-block-Poly(Dimethylsiloxane)-block-Poly(epsilon-Caprolactone). in Journal of Biomaterials Science-Polymer Edition. 2012;23(13):1629-1657.
doi:10.1163/092050611X589338 .

Pergal, Marija V., Antić, Vesna, Tovilović, Gordana, Nestorov, Jelena, Vasiljević-Radović, Dana, Djonlagić, Jasna, "In Vitro Biocompatibility Evaluation of Novel Urethane-Siloxane Co-Polymers Based on Poly(epsilon-Caprolactone)-block-Poly(Dimethylsiloxane)-block-Poly(epsilon-Caprolactone)" in Journal of Biomaterials Science-Polymer Edition, 23, no. 13 (2012):1629-1657,
https://doi.org/10.1163/092050611X589338 . .

TY  - JOUR
AU  - Balaban, Milica
AU  - Antić, Vesna
AU  - Pergal, Marija V.
AU  - Francolini, Iolanda
AU  - Martinelli, Andrea
AU  - Djonlagić, Jasna
PY  - 2012
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2969
AB  - Segmented poly(urethane-urea-siloxanes) (PUUS) based on 4,4'- methylene diphenyl diisocyanate-ethylene diamine (MDI-ED) hard segments and hydroxypropyl-terminated poly(dimethylsiloxane) (PDMS, Mn = 1000 g mol-1) soft segments were prepared under various experimental conditions. The copolymers with constant molar ratio of hard and soft segments (PDMS:MDI:ED = 1:2:1; 20 wt. % of the hard segments) were synthesized in two different solvent mixtures, by a two-step polyaddition procedure. The first one was tetrahydrofuran/N,N-dimethylacetamide (THF/DMAc) with different co-solvent ratios (1/1, 1/2 and 1/9, v/v), whereas the second one was tetrahydrofuran/N-methylpyrrolidone (THF/NMP, 1/9, v/v). The reaction conditions were optimized by varying the co-solvents ratio, the concentration of the catalyst, the initial monomer concentration, as well as the time of the first and the second step of the reaction. The effects of the experimental conditions on the size of the PUUS were investigated by gel permeation chromatography (GPC) and dilute solution viscometry. The copolymers with the highest molecular weights were obtained in the THF/NMP mixture (1/9, v/v). The structure and composition of the copolymers were determined by 1H-NMR and FTIR spectroscopy. The morphology of the synthesized copolymers was investigated by atomic force microscopy (AFM), while the thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The surface properties were evaluated by measuring the water contact angle (WCA). The copolymers exhibited phase-separated microstructure and were stable up to 200°C in nitrogen.
AB  - Segmentirani poli(uretan-urea-siloksani) (PUUS), sa tvrdim segmentima na bazi 4,4'-metilendifenildiizocijanata i etilendiamina (MDI-ED) i mekim segmentima na bazi hidroksipropil-terminiranog poli(dimetilsiloksana) (PDMS, Mn = 1000 g mol-1), sintetisani su pod različitim eksperimentalnim uslovima. Kopolimeri sa konstantnim molskim odnosom tvrdih i mekih segmenata (PDMS:MDI:ED = 1:2:1; 20 mas. % tvrdih segmenata), sintetisani su u dve različite smeše rastvarača kao reakcionog medijuma, metodom dvostepene poliadicije. Prva kombinacija rastvarača je bila smeša tetrahidrofurana (THF) i N,N-dimetilacetamida (DMAc), dok je u drugom slučaju korišćena smeša THF-a i N-metilpirolidona (NMP). Reakcioni uslovi su optimizovani u pogledu odnosa ko-rastvarača, koncentracije katalizatora, početne koncentracije monomera i vremena odigravanja prve i druge faze reakcije. Ispitan je uticaj primenjenih eksperimentalnih uslova na veličinu PUUS primenom gel-propusne hromatografije (GPC) i viskozimetrije razblaženih rastvora [η]. Kopolimeri najvećih molarnih masa su dobijeni u smeši THF/NMP (1/9, v/v). Struktura i sastav kopolimera su okarakterisani 1H-NMR i FTIR spektroskopijom. Morfologija sintetisanih kopolimera je ispitana mikroskopijom atomskih sila (AFM), dok su termička svojstva ispitana diferencijalnom skenirajućom kalorimetrijom (DSC) i termogravimetrijskom analizom (TGA). Površinska svojstva kopolimera su ispitana određivanjem kontaktnih uglova sa vodom (WCA). Kopolimeri su pokazali dvofaznu mikrostrukturu i bili su stabilni do 200°C u atmosteri azota.
PB  - Srpsko hemijsko društvo, Beograd
T2  - JOURNAL OF THE SERBIAN CHEMICAL SOCIETY
T1  - The effect of polar solvents on the synthesis of poly(urethane-urea-siloxane)s
T1  - Uticaj polarnih rastvarača na sintezu poli(uretan-urea-siloksana)
EP  - 1481
IS  - 10
SP  - 1457
VL  - 77
DO  - 10.2298/JSC111025056B
ER  - 

@article{
author = "Balaban, Milica and Antić, Vesna and Pergal, Marija V. and Francolini, Iolanda and Martinelli, Andrea and Djonlagić, Jasna",
year = "2012",
abstract = "Segmented poly(urethane-urea-siloxanes) (PUUS) based on 4,4'- methylene diphenyl diisocyanate-ethylene diamine (MDI-ED) hard segments and hydroxypropyl-terminated poly(dimethylsiloxane) (PDMS, Mn = 1000 g mol-1) soft segments were prepared under various experimental conditions. The copolymers with constant molar ratio of hard and soft segments (PDMS:MDI:ED = 1:2:1; 20 wt. % of the hard segments) were synthesized in two different solvent mixtures, by a two-step polyaddition procedure. The first one was tetrahydrofuran/N,N-dimethylacetamide (THF/DMAc) with different co-solvent ratios (1/1, 1/2 and 1/9, v/v), whereas the second one was tetrahydrofuran/N-methylpyrrolidone (THF/NMP, 1/9, v/v). The reaction conditions were optimized by varying the co-solvents ratio, the concentration of the catalyst, the initial monomer concentration, as well as the time of the first and the second step of the reaction. The effects of the experimental conditions on the size of the PUUS were investigated by gel permeation chromatography (GPC) and dilute solution viscometry. The copolymers with the highest molecular weights were obtained in the THF/NMP mixture (1/9, v/v). The structure and composition of the copolymers were determined by 1H-NMR and FTIR spectroscopy. The morphology of the synthesized copolymers was investigated by atomic force microscopy (AFM), while the thermal properties were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The surface properties were evaluated by measuring the water contact angle (WCA). The copolymers exhibited phase-separated microstructure and were stable up to 200°C in nitrogen., Segmentirani poli(uretan-urea-siloksani) (PUUS), sa tvrdim segmentima na bazi 4,4'-metilendifenildiizocijanata i etilendiamina (MDI-ED) i mekim segmentima na bazi hidroksipropil-terminiranog poli(dimetilsiloksana) (PDMS, Mn = 1000 g mol-1), sintetisani su pod različitim eksperimentalnim uslovima. Kopolimeri sa konstantnim molskim odnosom tvrdih i mekih segmenata (PDMS:MDI:ED = 1:2:1; 20 mas. % tvrdih segmenata), sintetisani su u dve različite smeše rastvarača kao reakcionog medijuma, metodom dvostepene poliadicije. Prva kombinacija rastvarača je bila smeša tetrahidrofurana (THF) i N,N-dimetilacetamida (DMAc), dok je u drugom slučaju korišćena smeša THF-a i N-metilpirolidona (NMP). Reakcioni uslovi su optimizovani u pogledu odnosa ko-rastvarača, koncentracije katalizatora, početne koncentracije monomera i vremena odigravanja prve i druge faze reakcije. Ispitan je uticaj primenjenih eksperimentalnih uslova na veličinu PUUS primenom gel-propusne hromatografije (GPC) i viskozimetrije razblaženih rastvora [η]. Kopolimeri najvećih molarnih masa su dobijeni u smeši THF/NMP (1/9, v/v). Struktura i sastav kopolimera su okarakterisani 1H-NMR i FTIR spektroskopijom. Morfologija sintetisanih kopolimera je ispitana mikroskopijom atomskih sila (AFM), dok su termička svojstva ispitana diferencijalnom skenirajućom kalorimetrijom (DSC) i termogravimetrijskom analizom (TGA). Površinska svojstva kopolimera su ispitana određivanjem kontaktnih uglova sa vodom (WCA). Kopolimeri su pokazali dvofaznu mikrostrukturu i bili su stabilni do 200°C u atmosteri azota.",
publisher = "Srpsko hemijsko društvo, Beograd",
journal = "JOURNAL OF THE SERBIAN CHEMICAL SOCIETY",
title = "The effect of polar solvents on the synthesis of poly(urethane-urea-siloxane)s, Uticaj polarnih rastvarača na sintezu poli(uretan-urea-siloksana)",
pages = "1481-1457",
number = "10",
volume = "77",
doi = "10.2298/JSC111025056B"
}

Balaban, M., Antić, V., Pergal, M. V., Francolini, I., Martinelli, A.,& Djonlagić, J.. (2012). The effect of polar solvents on the synthesis of poly(urethane-urea-siloxane)s. in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY
Srpsko hemijsko društvo, Beograd., 77(10), 1457-1481.
https://doi.org/10.2298/JSC111025056B

Balaban M, Antić V, Pergal MV, Francolini I, Martinelli A, Djonlagić J. The effect of polar solvents on the synthesis of poly(urethane-urea-siloxane)s. in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY. 2012;77(10):1457-1481.
doi:10.2298/JSC111025056B .

Balaban, Milica, Antić, Vesna, Pergal, Marija V., Francolini, Iolanda, Martinelli, Andrea, Djonlagić, Jasna, "The effect of polar solvents on the synthesis of poly(urethane-urea-siloxane)s" in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY, 77, no. 10 (2012):1457-1481,
https://doi.org/10.2298/JSC111025056B . .

TY  - JOUR
AU  - Pergal, Marija V.
AU  - Antić, Vesna
AU  - Govedarica, Milutin N.
AU  - Godjevac, Dejan
AU  - Ostojić, Sanja
AU  - Djonlagić, Jasna
PY  - 2011
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2675
AB  - Novel polyurethane copolymers derived from 4,4'-methylenediphenyl diisocyanate (MDI), 1,4-butanediol (BD) and alpha, omega-dihydroxy-[poly(caprolactone)-poly (dimethylsiloxane)-poly(caprolactone)] (a, x-dihydroxy( PCL-PDMS-PCL); (M) over bar (n) 6100 g mol(-1)) were synthesized by a two-step polyaddition reaction in solution. In the synthesis of the polyurethanes, the PCL blocks served as a compatibilizer between the nonpolar PDMS blocks and the polar comonomers, MDI and BD. The synthesis of thermoplastic polyurethanes (TPU) with high soft segment contents was optimized in terms of the concentrations of the reactants, the molar ratio of the NCO/OH groups, and the time and temperature of the polyaddition reaction. The structure, composition, and hard MDI/BD segment length of the synthesized polyurethane copolymers were determined by H-1, C-13-NMR, and two-dimensional correlation (COSY, HSQC, and HMBC) spectroscopy, while the hydrogen bonding interactions in the copolymers were analyzed by FT-IR spectroscopy. The influence of the reaction conditions on the structure, molecular weight, thermal, and some physical properties was studied at constant composition of the reaction mixture. A change in the molar ratio of the NCO/OH groups and the reaction conditions modified not only the molecular weight of the synthesized polyurethanes, but also the microstructure and therefore the thermal and physical properties of the copolymers. It was demonstrated that only PCL segments with high soft segment contents crystallize, thereby showing spherulitic morphology.
PB  - Wiley-Blackwell, Hoboken
T2  - Journal of Applied Polymer Science
T1  - Synthesis and Characterization of Novel Urethane-Siloxane Copolymers with a High Content of PCL-PDMS-PCL Segments
EP  - 2730
IS  - 4
SP  - 2715
VL  - 122
DO  - 10.1002/app.33926
ER  - 

@article{
author = "Pergal, Marija V. and Antić, Vesna and Govedarica, Milutin N. and Godjevac, Dejan and Ostojić, Sanja and Djonlagić, Jasna",
year = "2011",
abstract = "Novel polyurethane copolymers derived from 4,4'-methylenediphenyl diisocyanate (MDI), 1,4-butanediol (BD) and alpha, omega-dihydroxy-[poly(caprolactone)-poly (dimethylsiloxane)-poly(caprolactone)] (a, x-dihydroxy( PCL-PDMS-PCL); (M) over bar (n) 6100 g mol(-1)) were synthesized by a two-step polyaddition reaction in solution. In the synthesis of the polyurethanes, the PCL blocks served as a compatibilizer between the nonpolar PDMS blocks and the polar comonomers, MDI and BD. The synthesis of thermoplastic polyurethanes (TPU) with high soft segment contents was optimized in terms of the concentrations of the reactants, the molar ratio of the NCO/OH groups, and the time and temperature of the polyaddition reaction. The structure, composition, and hard MDI/BD segment length of the synthesized polyurethane copolymers were determined by H-1, C-13-NMR, and two-dimensional correlation (COSY, HSQC, and HMBC) spectroscopy, while the hydrogen bonding interactions in the copolymers were analyzed by FT-IR spectroscopy. The influence of the reaction conditions on the structure, molecular weight, thermal, and some physical properties was studied at constant composition of the reaction mixture. A change in the molar ratio of the NCO/OH groups and the reaction conditions modified not only the molecular weight of the synthesized polyurethanes, but also the microstructure and therefore the thermal and physical properties of the copolymers. It was demonstrated that only PCL segments with high soft segment contents crystallize, thereby showing spherulitic morphology.",
publisher = "Wiley-Blackwell, Hoboken",
journal = "Journal of Applied Polymer Science",
title = "Synthesis and Characterization of Novel Urethane-Siloxane Copolymers with a High Content of PCL-PDMS-PCL Segments",
pages = "2730-2715",
number = "4",
volume = "122",
doi = "10.1002/app.33926"
}

Pergal, M. V., Antić, V., Govedarica, M. N., Godjevac, D., Ostojić, S.,& Djonlagić, J.. (2011). Synthesis and Characterization of Novel Urethane-Siloxane Copolymers with a High Content of PCL-PDMS-PCL Segments. in Journal of Applied Polymer Science
Wiley-Blackwell, Hoboken., 122(4), 2715-2730.
https://doi.org/10.1002/app.33926

Pergal MV, Antić V, Govedarica MN, Godjevac D, Ostojić S, Djonlagić J. Synthesis and Characterization of Novel Urethane-Siloxane Copolymers with a High Content of PCL-PDMS-PCL Segments. in Journal of Applied Polymer Science. 2011;122(4):2715-2730.
doi:10.1002/app.33926 .

Pergal, Marija V., Antić, Vesna, Govedarica, Milutin N., Godjevac, Dejan, Ostojić, Sanja, Djonlagić, Jasna, "Synthesis and Characterization of Novel Urethane-Siloxane Copolymers with a High Content of PCL-PDMS-PCL Segments" in Journal of Applied Polymer Science, 122, no. 4 (2011):2715-2730,
https://doi.org/10.1002/app.33926 . .

TY  - JOUR
AU  - Pergal, Marija V.
AU  - Antić, Vesna
AU  - Ostojić, Sanja
AU  - Marinović-Cincović, Milena
AU  - Djonlagić, Jasna
PY  - 2011
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2697
AB  - A series of novel thermoplastic urethane-siloxane copolymers (TPUSs) based on a α,ω-dihydroxy-[poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b- -poly(ε-caprolactone)] (α,ω-dihydroxy-PCL-PDMS-PCL) triblock copolymer, 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BD) was synthesized. The effects of the content (9-63 mass %) of hard urethane segments and their degree of polymerization on the properties of the segmented TPUSs were investigated. The structure, composition and hard segment degree of polymerization of the hard segments were examined using 1H- and quantitative 13C-NMR spectroscopy. The degree of crystallinity of the synthesized copolymers was determined using wide-angle X-ray scattering (WAXS). The surface properties were evaluated by measuring the water contact angle and water absorption. In the series of the TPUSs, the average degree of polymerization of the hard segments was varied from 1.2 to 14.4 MDI-BD units. It was found that average values from 3.8 to 14.4 MDI-BD units were effective segment lengths for crystallization of hard segments, which resulted in an increase in the degree of microphase separation of the copolymers. Spherulite-like superstructures were observed in copolymer films by scanning electron microscopy (SEM), which are believed to arise from the crystallization of the hard segments and/or PCL segments, depending on the content of the hard segments. The surface of the copolymers became more hydrophobic with increasing weight fraction of PDMS. The synthesized copolymers based on a PCL-PDMS-PCL segment showed good thermal stability, which increased with increasing content of soft PDMS segments, as was confirmed by the value of the starting temperature of thermal degradation.
AB  - U ovom radu prikazana je struktura i neka svojstva serije novih termoplastičnih uretan-siloksanskih kopolimera (TPUSs) na bazi α,ω-dihidroksi-[poli(ε-kaprolakton)-b-poli(dimetilsiloksan)-b-poli(ε-kaprolakton)] triblok kopolimera (α,ω-dihidroksi-PCL-PDMS-PCL), 4,4'-metilendifenildiizocijanata (MDI) i 1,4-butandiola (BD). Ispitan je uticaj sadržaja uretanskog tvrdog segmenta (9-63 mas. %) i njegove dužine, tj. stepena polimerizacije, izražene preko broja MDI-BD ostataka, na svojstva segmentiranih TPUSs. Struktura, sastav i stepen polimerizacije tvrdog segmenta su ispitani pomoću 1H- i kvantitativne 13C-NMR spektroskopije. Stepen kristaliničnosti kopolimera je određen metodom difrakcije X-zraka na velikim uglovima (WAXS). Površinska svojstva kopolimera su ispitana određivanjem kontaktnih uglova sa vodom i merenjem apsorpcije vode. U seriji kopolimera dužina tvrdog segmenta izražena preko broja ponavljajućih MDI-BD jedinica je varirana od 1,2 do 14,4. Utvrđeno je da tvrdi segmenti sa 3,8 do 14,4 ponavljajućih MDI-BD jedinica efikasno kristališu, što je rezultovalo u povećanju stepena mikrofazne separacije kopolimera. SEM analiza je pokazala prisustvo sferulitne strukture u kopolimernim filmovima, koja najverovatnije potiče od kristalizacije tvrdih i/ili PCL segmenata, zavisno od sadržaja tvrdih segmenata. Hidrofobnost površine kopolimera je rasla sa povećanjem masenog udela PDMS-a u odgovarajućem uzorku. Sintetisani poliuretani na bazi PCL-PDMS-PCL pokazuju povećanje termičke stabilnosti sa povećanjem sadržaja mekih PDMS segmenata, što je potvrđeno porastom početne temperature degradacije, određene TG analizom.
PB  - Srpsko hemijsko društvo, Beograd
T2  - JOURNAL OF THE SERBIAN CHEMICAL SOCIETY
T1  - Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε-caprolactone) triblock copolymer
T1  - Uticaj sadržaja tvrdog segmenta na svojstva novih uretan-siloksanskih kopolimera na bazi poli(e-kaprolakton)-b-poli(dimetilsiloksan)-b-poli(e-kaprolaktona)
EP  - 1723
IS  - 12
SP  - 1703
VL  - 76
DO  - 10.2298/JSC110307146P
ER  - 

@article{
author = "Pergal, Marija V. and Antić, Vesna and Ostojić, Sanja and Marinović-Cincović, Milena and Djonlagić, Jasna",
year = "2011",
abstract = "A series of novel thermoplastic urethane-siloxane copolymers (TPUSs) based on a α,ω-dihydroxy-[poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b- -poly(ε-caprolactone)] (α,ω-dihydroxy-PCL-PDMS-PCL) triblock copolymer, 4,4'-methylenediphenyl diisocyanate (MDI) and 1,4-butanediol (BD) was synthesized. The effects of the content (9-63 mass %) of hard urethane segments and their degree of polymerization on the properties of the segmented TPUSs were investigated. The structure, composition and hard segment degree of polymerization of the hard segments were examined using 1H- and quantitative 13C-NMR spectroscopy. The degree of crystallinity of the synthesized copolymers was determined using wide-angle X-ray scattering (WAXS). The surface properties were evaluated by measuring the water contact angle and water absorption. In the series of the TPUSs, the average degree of polymerization of the hard segments was varied from 1.2 to 14.4 MDI-BD units. It was found that average values from 3.8 to 14.4 MDI-BD units were effective segment lengths for crystallization of hard segments, which resulted in an increase in the degree of microphase separation of the copolymers. Spherulite-like superstructures were observed in copolymer films by scanning electron microscopy (SEM), which are believed to arise from the crystallization of the hard segments and/or PCL segments, depending on the content of the hard segments. The surface of the copolymers became more hydrophobic with increasing weight fraction of PDMS. The synthesized copolymers based on a PCL-PDMS-PCL segment showed good thermal stability, which increased with increasing content of soft PDMS segments, as was confirmed by the value of the starting temperature of thermal degradation., U ovom radu prikazana je struktura i neka svojstva serije novih termoplastičnih uretan-siloksanskih kopolimera (TPUSs) na bazi α,ω-dihidroksi-[poli(ε-kaprolakton)-b-poli(dimetilsiloksan)-b-poli(ε-kaprolakton)] triblok kopolimera (α,ω-dihidroksi-PCL-PDMS-PCL), 4,4'-metilendifenildiizocijanata (MDI) i 1,4-butandiola (BD). Ispitan je uticaj sadržaja uretanskog tvrdog segmenta (9-63 mas. %) i njegove dužine, tj. stepena polimerizacije, izražene preko broja MDI-BD ostataka, na svojstva segmentiranih TPUSs. Struktura, sastav i stepen polimerizacije tvrdog segmenta su ispitani pomoću 1H- i kvantitativne 13C-NMR spektroskopije. Stepen kristaliničnosti kopolimera je određen metodom difrakcije X-zraka na velikim uglovima (WAXS). Površinska svojstva kopolimera su ispitana određivanjem kontaktnih uglova sa vodom i merenjem apsorpcije vode. U seriji kopolimera dužina tvrdog segmenta izražena preko broja ponavljajućih MDI-BD jedinica je varirana od 1,2 do 14,4. Utvrđeno je da tvrdi segmenti sa 3,8 do 14,4 ponavljajućih MDI-BD jedinica efikasno kristališu, što je rezultovalo u povećanju stepena mikrofazne separacije kopolimera. SEM analiza je pokazala prisustvo sferulitne strukture u kopolimernim filmovima, koja najverovatnije potiče od kristalizacije tvrdih i/ili PCL segmenata, zavisno od sadržaja tvrdih segmenata. Hidrofobnost površine kopolimera je rasla sa povećanjem masenog udela PDMS-a u odgovarajućem uzorku. Sintetisani poliuretani na bazi PCL-PDMS-PCL pokazuju povećanje termičke stabilnosti sa povećanjem sadržaja mekih PDMS segmenata, što je potvrđeno porastom početne temperature degradacije, određene TG analizom.",
publisher = "Srpsko hemijsko društvo, Beograd",
journal = "JOURNAL OF THE SERBIAN CHEMICAL SOCIETY",
title = "Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε-caprolactone) triblock copolymer, Uticaj sadržaja tvrdog segmenta na svojstva novih uretan-siloksanskih kopolimera na bazi poli(e-kaprolakton)-b-poli(dimetilsiloksan)-b-poli(e-kaprolaktona)",
pages = "1723-1703",
number = "12",
volume = "76",
doi = "10.2298/JSC110307146P"
}

Pergal, M. V., Antić, V., Ostojić, S., Marinović-Cincović, M.,& Djonlagić, J.. (2011). Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε-caprolactone) triblock copolymer. in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY
Srpsko hemijsko društvo, Beograd., 76(12), 1703-1723.
https://doi.org/10.2298/JSC110307146P

Pergal MV, Antić V, Ostojić S, Marinović-Cincović M, Djonlagić J. Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε-caprolactone) triblock copolymer. in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY. 2011;76(12):1703-1723.
doi:10.2298/JSC110307146P .

Pergal, Marija V., Antić, Vesna, Ostojić, Sanja, Marinović-Cincović, Milena, Djonlagić, Jasna, "Influence of the content of hard segments on the properties of novel urethane-siloxane copolymers based on a poly(ε-caprolactone)-b-poly(dimethylsiloxane)-b-poly(ε-caprolactone) triblock copolymer" in JOURNAL OF THE SERBIAN CHEMICAL SOCIETY, 76, no. 12 (2011):1703-1723,
https://doi.org/10.2298/JSC110307146P . .

TY  - JOUR
AU  - Antić, Vesna
AU  - Pergal, Marija V.
AU  - Antić, Mališa
AU  - Djonlagić, Jasna
PY  - 2010
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/2261
AB  - Two series of thermoplastic elastomers (TPES), based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were analyzed by dynamic mechanical spectroscopy. In the first TPES series the lengths of both hard and soft segments were varied while the mass ratio of the hard to soft segments was nearly constant (about 60 mass%). In the second series, the mass ratio of hard and soft segments was varied in the range from 60/40 to 40/60, with a constant length of soft PDMS segments. The influence of the structure and composition of TPESs on the rheological properties, such as complex dynamic viscosity, μ*, the storage, G', and loss, G', shear modulus as well as the microphase separation transition temperature, TMST, was examined. The obtained results showed that the storage modulus of the TPESs increased in a rubbery plateau region with increase in degree of crystallinity. The rheological measurements of TPESs also showed that a microphase reorganization occurred during the melting process. The microphase separation transition temperatures were in the range from 220 to 234°C. In the isotropic molten state, the complex dynamic viscosity increased with increasing both the content and length of hard PBT segments.
AB  - Dve serije termoplastičnih elastomera (TPES) na bazi poli(dimetilsiloksana) kao mekog segmenta i poli(butilentereftalata) kao tvrdog segmenta su analizirane dinamičko-mehaničkom spektroskopijom. U prvoj TPES seriji varirane su dužine tvrdih i mekih segmenata dok je njihov maseni odnos bio skoro konstantan (oko 60 mas%). U drugoj seriji, odnos tvrdih i mekih segmenata je variran u opsegu od 60/40 do 40/60, dok je dužina mekih PDMS segmenata bila konstantna. Ispitan je uticaj strukture i sastava TPES kopolimera na reološka svojstva, kao što su kompleksni dinamički viskozitet, μ*, moduli sačuvane, G', i izgubljene energije, G', i temperatura mikrofaznog razdvajanja, TMST. Dobijeni rezultati su pokazali da su uzorci sa većim stepenom kristaliničnosti imali i veće module sačuvane energije u gumolikom platou. Reološka merenja su takođe pokazala da svi TPES uzorci ispoljavaju mikrofaznu reorganizaciju u procesu topljenja. Temperature mikrofaznog razdvajanja su bile u opsegu od 220 do 234°C. U izotropskom rastopu, kompleksni dinamički viskoziteti su rasli sa povećanjem sadržaja i dužine PBT segmenata.
PB  - Savez hemijskih inženjera, Beograd
T2  - Hemijska industrija
T1  - Rheological behaviour of thermoplastic poly(ester-siloxane)s
T1  - Reološko ponašanje termoplastičnih poli(estar-siloksana)
EP  - 545
IS  - 6
SP  - 537
VL  - 64
DO  - 10.2298/HEMIND101015067A
ER  - 

@article{
author = "Antić, Vesna and Pergal, Marija V. and Antić, Mališa and Djonlagić, Jasna",
year = "2010",
abstract = "Two series of thermoplastic elastomers (TPES), based on poly(dimethylsiloxane) (PDMS) as the soft segment and poly(butylene terephthalate) (PBT) as the hard segment, were analyzed by dynamic mechanical spectroscopy. In the first TPES series the lengths of both hard and soft segments were varied while the mass ratio of the hard to soft segments was nearly constant (about 60 mass%). In the second series, the mass ratio of hard and soft segments was varied in the range from 60/40 to 40/60, with a constant length of soft PDMS segments. The influence of the structure and composition of TPESs on the rheological properties, such as complex dynamic viscosity, μ*, the storage, G', and loss, G', shear modulus as well as the microphase separation transition temperature, TMST, was examined. The obtained results showed that the storage modulus of the TPESs increased in a rubbery plateau region with increase in degree of crystallinity. The rheological measurements of TPESs also showed that a microphase reorganization occurred during the melting process. The microphase separation transition temperatures were in the range from 220 to 234°C. In the isotropic molten state, the complex dynamic viscosity increased with increasing both the content and length of hard PBT segments., Dve serije termoplastičnih elastomera (TPES) na bazi poli(dimetilsiloksana) kao mekog segmenta i poli(butilentereftalata) kao tvrdog segmenta su analizirane dinamičko-mehaničkom spektroskopijom. U prvoj TPES seriji varirane su dužine tvrdih i mekih segmenata dok je njihov maseni odnos bio skoro konstantan (oko 60 mas%). U drugoj seriji, odnos tvrdih i mekih segmenata je variran u opsegu od 60/40 do 40/60, dok je dužina mekih PDMS segmenata bila konstantna. Ispitan je uticaj strukture i sastava TPES kopolimera na reološka svojstva, kao što su kompleksni dinamički viskozitet, μ*, moduli sačuvane, G', i izgubljene energije, G', i temperatura mikrofaznog razdvajanja, TMST. Dobijeni rezultati su pokazali da su uzorci sa većim stepenom kristaliničnosti imali i veće module sačuvane energije u gumolikom platou. Reološka merenja su takođe pokazala da svi TPES uzorci ispoljavaju mikrofaznu reorganizaciju u procesu topljenja. Temperature mikrofaznog razdvajanja su bile u opsegu od 220 do 234°C. U izotropskom rastopu, kompleksni dinamički viskoziteti su rasli sa povećanjem sadržaja i dužine PBT segmenata.",
publisher = "Savez hemijskih inženjera, Beograd",
journal = "Hemijska industrija",
title = "Rheological behaviour of thermoplastic poly(ester-siloxane)s, Reološko ponašanje termoplastičnih poli(estar-siloksana)",
pages = "545-537",
number = "6",
volume = "64",
doi = "10.2298/HEMIND101015067A"
}

Antić, V., Pergal, M. V., Antić, M.,& Djonlagić, J.. (2010). Rheological behaviour of thermoplastic poly(ester-siloxane)s. in Hemijska industrija
Savez hemijskih inženjera, Beograd., 64(6), 537-545.
https://doi.org/10.2298/HEMIND101015067A

Antić V, Pergal MV, Antić M, Djonlagić J. Rheological behaviour of thermoplastic poly(ester-siloxane)s. in Hemijska industrija. 2010;64(6):537-545.
doi:10.2298/HEMIND101015067A .

Antić, Vesna, Pergal, Marija V., Antić, Mališa, Djonlagić, Jasna, "Rheological behaviour of thermoplastic poly(ester-siloxane)s" in Hemijska industrija, 64, no. 6 (2010):537-545,
https://doi.org/10.2298/HEMIND101015067A . .

TY  - JOUR
AU  - Manojlović, Verica
AU  - Rajić, Nevenka
AU  - Djonlagić, Jasna
AU  - Obradović, Bojana
AU  - Nedović, Viktor
AU  - Bugarski, Branko
PY  - 2008
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1836
AB  - The subject of this study was the development of flavour alginate formulations aimed for thermally processed foods. Ethyl vanilline was used as the model flavour compound. Electrostatic extrusion was applied for the encapsulation of ethyl vanilline in alginate gel microbeads. The obtained microbeads with approx. 10 % w/w of ethyl vanilline encapsulated in about 2 % w/w alginate were uniformly sized spheres of about 450 mu m. Chemical characterization by H-NMR spectroscopy revealed that the alginate used in this study had a high content ( 67 %) of guluronic residues and was rich in GG diad blocks (F-GG = 55%) and thus presented a high-quality immobilisation matrix. The thermal behaviour of alginate beads encapsulating ethyl vanilline was investigated by thermogravimetric (TG) and differential scanning calorimetry measurements (TG-DSC) under heating conditions which mimicked usual food processing to provide information about thermal decomposition of alginate matrix and kinetics of aroma release. Two well resolved weight losses were observed. The first one was in the 50-150 degrees C temperature range with the maximum at approx. 112 C, corresponding to the dehydration of the polymer network. The second loss in the 220-325 degrees C temperature range, with a maximum at similar to 247 degrees C corresponded to the release of vanilline. The obtained results indicate that up to 230 degrees C most of the vanilline remained intacta, while prolonged heating at elevated temperatures led to the entire loss of the aroma compound.
PB  - MDPI, BASEL
T2  - Sensors
T1  - Application of electrostatic extrusion - Flavour encapsulation and controlled release
EP  - 1496
IS  - 3
SP  - 1488
VL  - 8
DO  - 10.3390/s8031488
ER  - 

@article{
author = "Manojlović, Verica and Rajić, Nevenka and Djonlagić, Jasna and Obradović, Bojana and Nedović, Viktor and Bugarski, Branko",
year = "2008",
abstract = "The subject of this study was the development of flavour alginate formulations aimed for thermally processed foods. Ethyl vanilline was used as the model flavour compound. Electrostatic extrusion was applied for the encapsulation of ethyl vanilline in alginate gel microbeads. The obtained microbeads with approx. 10 % w/w of ethyl vanilline encapsulated in about 2 % w/w alginate were uniformly sized spheres of about 450 mu m. Chemical characterization by H-NMR spectroscopy revealed that the alginate used in this study had a high content ( 67 %) of guluronic residues and was rich in GG diad blocks (F-GG = 55%) and thus presented a high-quality immobilisation matrix. The thermal behaviour of alginate beads encapsulating ethyl vanilline was investigated by thermogravimetric (TG) and differential scanning calorimetry measurements (TG-DSC) under heating conditions which mimicked usual food processing to provide information about thermal decomposition of alginate matrix and kinetics of aroma release. Two well resolved weight losses were observed. The first one was in the 50-150 degrees C temperature range with the maximum at approx. 112 C, corresponding to the dehydration of the polymer network. The second loss in the 220-325 degrees C temperature range, with a maximum at similar to 247 degrees C corresponded to the release of vanilline. The obtained results indicate that up to 230 degrees C most of the vanilline remained intacta, while prolonged heating at elevated temperatures led to the entire loss of the aroma compound.",
publisher = "MDPI, BASEL",
journal = "Sensors",
title = "Application of electrostatic extrusion - Flavour encapsulation and controlled release",
pages = "1496-1488",
number = "3",
volume = "8",
doi = "10.3390/s8031488"
}

Manojlović, V., Rajić, N., Djonlagić, J., Obradović, B., Nedović, V.,& Bugarski, B.. (2008). Application of electrostatic extrusion - Flavour encapsulation and controlled release. in Sensors
MDPI, BASEL., 8(3), 1488-1496.
https://doi.org/10.3390/s8031488

Manojlović V, Rajić N, Djonlagić J, Obradović B, Nedović V, Bugarski B. Application of electrostatic extrusion - Flavour encapsulation and controlled release. in Sensors. 2008;8(3):1488-1496.
doi:10.3390/s8031488 .

Manojlović, Verica, Rajić, Nevenka, Djonlagić, Jasna, Obradović, Bojana, Nedović, Viktor, Bugarski, Branko, "Application of electrostatic extrusion - Flavour encapsulation and controlled release" in Sensors, 8, no. 3 (2008):1488-1496,
https://doi.org/10.3390/s8031488 . .

TY  - JOUR
AU  - Manojlović, Verica
AU  - Djonlagić, Jasna
AU  - Obradović, B.
AU  - Nedović, Viktor
AU  - Bugarski, Branko
PY  - 2006
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1302
AB  - The process of electrostatic extrusion as a method for cell immobilization was investigated that could be used for potential applications in medicine. An attempt was made to assess the effects of cell addition and polymer concentration on the overall entrapment procedure, ie, on each stage of immobilization: polymer-cell suspension rheological characteristics, electrostatic extrusion process, and the process of gelation. The findings should contribute to a better understanding of polymer-cell interactions, which could be crucial in possible medical treatments. Alginate-yeast was used as a model system for carrier-cells. The electrostatic extrusion was considered as a complex two-phase flow system and the effects of cell and alginate concentrations on the resulting microbead size and uniformity were assessed. Under investigated conditions, microbeads 50-600 mu m in diameter were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with higher standard deviations in size. We attempted to rationalize the findings by rheological characterization of the cell-alginate suspensions. Rheological characterization revealed non-Newtonian, pseudoplastic behavior of cell-alginate suspensions with higher viscosities at higher alginate concentrations. However, the presence of cells even at high concentrations (5x10(8) and 1x10(9) cells/mL) did not significantly affect the rheological properties of Na-alginate solution. Lastly, we investigated the kinetics of alginate gelation with respect to the quantity of Ca2+ ions and cell presence. The gelation kinetics were examined under conditions of limited supply with Ca2+ ions, which can be essential for immobilization of highly sensitive mammalian cells that require minimal exposure to CaCl2 solution. The molar ratio of G units to Ca2+ ions of 3.8:1 provided complete crosslinking, while the increase in alginate concentration resulted in prolonged gelation times but higher strength of the resulting gel. The cell presence decreased the rate of network formation as well as the strength of the obtained Ca-alginate hydrogel.
PB  - Dove Medical Press Ltd, Albany
T2  - International Journal of Nanomedicine
T1  - Immobilization of cells by electrostatic droplet generation: a model system for potential application in medicine
EP  - 171
IS  - 2
SP  - 163
VL  - 1
DO  - 10.2147/nano.2006.1.2.163
ER  - 

@article{
author = "Manojlović, Verica and Djonlagić, Jasna and Obradović, B. and Nedović, Viktor and Bugarski, Branko",
year = "2006",
abstract = "The process of electrostatic extrusion as a method for cell immobilization was investigated that could be used for potential applications in medicine. An attempt was made to assess the effects of cell addition and polymer concentration on the overall entrapment procedure, ie, on each stage of immobilization: polymer-cell suspension rheological characteristics, electrostatic extrusion process, and the process of gelation. The findings should contribute to a better understanding of polymer-cell interactions, which could be crucial in possible medical treatments. Alginate-yeast was used as a model system for carrier-cells. The electrostatic extrusion was considered as a complex two-phase flow system and the effects of cell and alginate concentrations on the resulting microbead size and uniformity were assessed. Under investigated conditions, microbeads 50-600 mu m in diameter were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with higher standard deviations in size. We attempted to rationalize the findings by rheological characterization of the cell-alginate suspensions. Rheological characterization revealed non-Newtonian, pseudoplastic behavior of cell-alginate suspensions with higher viscosities at higher alginate concentrations. However, the presence of cells even at high concentrations (5x10(8) and 1x10(9) cells/mL) did not significantly affect the rheological properties of Na-alginate solution. Lastly, we investigated the kinetics of alginate gelation with respect to the quantity of Ca2+ ions and cell presence. The gelation kinetics were examined under conditions of limited supply with Ca2+ ions, which can be essential for immobilization of highly sensitive mammalian cells that require minimal exposure to CaCl2 solution. The molar ratio of G units to Ca2+ ions of 3.8:1 provided complete crosslinking, while the increase in alginate concentration resulted in prolonged gelation times but higher strength of the resulting gel. The cell presence decreased the rate of network formation as well as the strength of the obtained Ca-alginate hydrogel.",
publisher = "Dove Medical Press Ltd, Albany",
journal = "International Journal of Nanomedicine",
title = "Immobilization of cells by electrostatic droplet generation: a model system for potential application in medicine",
pages = "171-163",
number = "2",
volume = "1",
doi = "10.2147/nano.2006.1.2.163"
}

Manojlović, V., Djonlagić, J., Obradović, B., Nedović, V.,& Bugarski, B.. (2006). Immobilization of cells by electrostatic droplet generation: a model system for potential application in medicine. in International Journal of Nanomedicine
Dove Medical Press Ltd, Albany., 1(2), 163-171.
https://doi.org/10.2147/nano.2006.1.2.163

Manojlović V, Djonlagić J, Obradović B, Nedović V, Bugarski B. Immobilization of cells by electrostatic droplet generation: a model system for potential application in medicine. in International Journal of Nanomedicine. 2006;1(2):163-171.
doi:10.2147/nano.2006.1.2.163 .

Manojlović, Verica, Djonlagić, Jasna, Obradović, B., Nedović, Viktor, Bugarski, Branko, "Immobilization of cells by electrostatic droplet generation: a model system for potential application in medicine" in International Journal of Nanomedicine, 1, no. 2 (2006):163-171,
https://doi.org/10.2147/nano.2006.1.2.163 . .

TY  - CONF
AU  - Manojlović, Verica
AU  - Djonlagić, Jasna
AU  - Obradović, B
AU  - Nedović, Viktor
AU  - Bugarski, Branko
PY  - 2006
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1260
AB  - In this study, the process of electrostatic extrusion as a method for cell immobilization was investigated. We have assessed the effects of concentrations of yeast cells (as a model cell type) and Na alginate on the size of the resulting microbeads and attempted to rationalize the obtained findings by rheological characterization of the cell-alginate suspensions. Under the investigated conditions, microbeads, 50-600 mu m in diameter, were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with their sizes having higher standard deviations. Rheological characterization revealed non-Newtonian, pseudoplastic behavior of cell-alginate suspensions with higher viscosities at higher alginate concentrations. However, the presence of cells even at high concentrations (5 x 10(8) and 1 x 10(9) cells mL(-1)) did not significantly affect the rheological properties of the Na alginate solution. Finally, we have investigated the kinetics of alginate gelation with respect to the quantity of Ca2+ ions and the presence of cells. The molar ratio of alpha-L-guluronic acid units to Ca2+ ions of 4:1 provided complete crosslinking. The presence of cells decreased the rate of network formation as well as the strength of the obtained Ca alginate hydrogel.
PB  - Wiley, Hoboken
C3  - Journal of Chemical Technology and Biotechnology
T1  - Investigations of cell immobilization in alginate: rheological and electrostatic extrusion studies
EP  - 510
IS  - 4
SP  - 505
VL  - 81
DO  - 10.1002/jctb.1465
ER  - 

@conference{
author = "Manojlović, Verica and Djonlagić, Jasna and Obradović, B and Nedović, Viktor and Bugarski, Branko",
year = "2006",
abstract = "In this study, the process of electrostatic extrusion as a method for cell immobilization was investigated. We have assessed the effects of concentrations of yeast cells (as a model cell type) and Na alginate on the size of the resulting microbeads and attempted to rationalize the obtained findings by rheological characterization of the cell-alginate suspensions. Under the investigated conditions, microbeads, 50-600 mu m in diameter, were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with their sizes having higher standard deviations. Rheological characterization revealed non-Newtonian, pseudoplastic behavior of cell-alginate suspensions with higher viscosities at higher alginate concentrations. However, the presence of cells even at high concentrations (5 x 10(8) and 1 x 10(9) cells mL(-1)) did not significantly affect the rheological properties of the Na alginate solution. Finally, we have investigated the kinetics of alginate gelation with respect to the quantity of Ca2+ ions and the presence of cells. The molar ratio of alpha-L-guluronic acid units to Ca2+ ions of 4:1 provided complete crosslinking. The presence of cells decreased the rate of network formation as well as the strength of the obtained Ca alginate hydrogel.",
publisher = "Wiley, Hoboken",
journal = "Journal of Chemical Technology and Biotechnology",
title = "Investigations of cell immobilization in alginate: rheological and electrostatic extrusion studies",
pages = "510-505",
number = "4",
volume = "81",
doi = "10.1002/jctb.1465"
}

Manojlović, V., Djonlagić, J., Obradović, B., Nedović, V.,& Bugarski, B.. (2006). Investigations of cell immobilization in alginate: rheological and electrostatic extrusion studies. in Journal of Chemical Technology and Biotechnology
Wiley, Hoboken., 81(4), 505-510.
https://doi.org/10.1002/jctb.1465

Manojlović V, Djonlagić J, Obradović B, Nedović V, Bugarski B. Investigations of cell immobilization in alginate: rheological and electrostatic extrusion studies. in Journal of Chemical Technology and Biotechnology. 2006;81(4):505-510.
doi:10.1002/jctb.1465 .

Manojlović, Verica, Djonlagić, Jasna, Obradović, B, Nedović, Viktor, Bugarski, Branko, "Investigations of cell immobilization in alginate: rheological and electrostatic extrusion studies" in Journal of Chemical Technology and Biotechnology, 81, no. 4 (2006):505-510,
https://doi.org/10.1002/jctb.1465 . .

TY  - JOUR
AU  - Nedović, Viktor
AU  - Manojlović, Verica
AU  - Pruesse, Ulf
AU  - Bugarski, Branko
AU  - Djonlagić, Jasna
AU  - Vorlop, Klaus D.
PY  - 2006
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/1224
AB  - The aim of this study was to optimize the electrostatic extrusion process for producing small, spherical and uniform microbeads with different fluid viscosities by varying the operating parameters in very wide ranges. Alginate was used as a model polymer. Since the rheological behavior of the solution is one of the parameters that affects the flow dynamics during extrusion, viscosity measurements of solutions with different alginate content were performed. The results obtained in this study show that an electrostatic droplet generator can be used for the production of spherical microbeads of narrow size distribution from low- and medium- viscous fluids (0.5, 1, and 2% of alginate). The average microbead diameter for low-viscous solutions was less than 100 micrometers. It was possible to obtain beads smaller than 500 micrometers that were very uniform (standard deviations less than 2.5%) and of spherical (the shape distortion was less than 1%) from medium-viscous alginate solution (2%). By reducing the polymer flowrate to less than 1 ml/h, even smaller microbeads were produced with diameters of about 300 micrometers. The particular contribution of this paper is in exceeding limitations regarding the use of high-viscous polymer solutions. Optimization of the operating conditions that included the use of a very small needle (0.15 mm), enlargement of the electrode distance to more than 20 cm and a severe reduction in the polymer flow rate to lower than 5 ml/h (for 3% alginate) or 1 ml/h (for 4% alginate) enabled the production of small, entirely spherical and uniform microbeads with an average microbead diameter lower than 500 and 700 micrometers in the case of 3 and 4% of alginate, respectively.
AB  - Elektrostatička ekstruzija je novija ekstruziona metoda koja se zasniva na primeni električne sile koja deluje na površini meniskusa tečnosti na vrhu igle, usled čega dolazi do generisanja velikog broja kapljica. U prethodnim istraživanjima je utvrđeno da je veličina čestica funkcija više parametara kao što su električni potencijal, prečnik kapilare, rastojanje između elektroda, protok i fizičko-hemijske osobine polimera (površinski napon viskoznost, koncentracija). Takođe, utvrđeno je i da postoje određena ograničenja koja se odnose na ekstruziju veoma viskoznih rastvora. Ovaj rad je posvećen optimizaciji metode radi dobijanja što sitnijih i uniformnijih čestica. S obzirom da je viskoznost rastvora jedan od parametara koji utiče na dinamiku isticanja polimera kroz kapilaru, najpre su izvršena merenja viskoznosti rastvora alginata različitih koncentracija. Utvrđeno je da povećanje koncentracije rastvora sa 2 do 4% dovodi do povećanja viskoznosti sa oko 2000 na 17000 mPas na 21 °C. Dobijeni rezultati su pokazali da je elektrostička ekstruzija vrlo povoljna za dobijanje sferičnih čestica uskog opsega raspodele veličina koristeći nisko- i srednje-viskozne rastvore polimera (0,5, 1 i 2% alginata). Sa nisko-viskoznim rastvorom alginata, pod određenim uslovima, dobijene su čestice čiji je srednji prečnik čak manji i od 100 μn. Sa srednje viskoznim alginatnim rastvorom dobijene su čestice prečnika ispod 500 μm, koje su bile vrlo uniformne (srednje kvadratno odstupanje manje od 2,5%) i sferične (deformacija oblika manja od 1%), a smanjenjem protoka rastvora, moguće je dobiti čestice i manje od 300 μm. Poseban doprinos rada je u prevazilaženju ograničenja koja se odnose na ekstruziju veoma viskoznih rastvora. Optimizacija procesnih parametara koja je podrazumevala primenu vrlo tanke igle (0,15 mm), povećanje rastojanja između elektroda iznad 20 cm i smanjenje protoka ispod 5 ml/h (za 3% alginat), odn. 1 ml/h (za 4% alginat), omogućila je dobijanje malih, potpuno sferičnih i uniformnih mikročestica čiji je srednji prečnik bio ispod 500 i 700 μm za 3 i 4% alginatni rastvor, respektivno.
PB  - Savez hemijskih inženjera, Beograd
T2  - Chemical Industry and Chemical Engineering Quarterly / CICEQ
T1  - Optimization of the electrostatic droplet generation process for controlled microbead production: Single nozzle system
T1  - Optimizacija elektrostatičkog generisanja čestica u cilju kontrolisanja njihovih mikronskih veličina - sistem sa jednom mlaznicom
EP  - 57
IS  - 1
SP  - 53
VL  - 12
DO  - 10.2298/CICEQ0601053N
ER  - 

@article{
author = "Nedović, Viktor and Manojlović, Verica and Pruesse, Ulf and Bugarski, Branko and Djonlagić, Jasna and Vorlop, Klaus D.",
year = "2006",
abstract = "The aim of this study was to optimize the electrostatic extrusion process for producing small, spherical and uniform microbeads with different fluid viscosities by varying the operating parameters in very wide ranges. Alginate was used as a model polymer. Since the rheological behavior of the solution is one of the parameters that affects the flow dynamics during extrusion, viscosity measurements of solutions with different alginate content were performed. The results obtained in this study show that an electrostatic droplet generator can be used for the production of spherical microbeads of narrow size distribution from low- and medium- viscous fluids (0.5, 1, and 2% of alginate). The average microbead diameter for low-viscous solutions was less than 100 micrometers. It was possible to obtain beads smaller than 500 micrometers that were very uniform (standard deviations less than 2.5%) and of spherical (the shape distortion was less than 1%) from medium-viscous alginate solution (2%). By reducing the polymer flowrate to less than 1 ml/h, even smaller microbeads were produced with diameters of about 300 micrometers. The particular contribution of this paper is in exceeding limitations regarding the use of high-viscous polymer solutions. Optimization of the operating conditions that included the use of a very small needle (0.15 mm), enlargement of the electrode distance to more than 20 cm and a severe reduction in the polymer flow rate to lower than 5 ml/h (for 3% alginate) or 1 ml/h (for 4% alginate) enabled the production of small, entirely spherical and uniform microbeads with an average microbead diameter lower than 500 and 700 micrometers in the case of 3 and 4% of alginate, respectively., Elektrostatička ekstruzija je novija ekstruziona metoda koja se zasniva na primeni električne sile koja deluje na površini meniskusa tečnosti na vrhu igle, usled čega dolazi do generisanja velikog broja kapljica. U prethodnim istraživanjima je utvrđeno da je veličina čestica funkcija više parametara kao što su električni potencijal, prečnik kapilare, rastojanje između elektroda, protok i fizičko-hemijske osobine polimera (površinski napon viskoznost, koncentracija). Takođe, utvrđeno je i da postoje određena ograničenja koja se odnose na ekstruziju veoma viskoznih rastvora. Ovaj rad je posvećen optimizaciji metode radi dobijanja što sitnijih i uniformnijih čestica. S obzirom da je viskoznost rastvora jedan od parametara koji utiče na dinamiku isticanja polimera kroz kapilaru, najpre su izvršena merenja viskoznosti rastvora alginata različitih koncentracija. Utvrđeno je da povećanje koncentracije rastvora sa 2 do 4% dovodi do povećanja viskoznosti sa oko 2000 na 17000 mPas na 21 °C. Dobijeni rezultati su pokazali da je elektrostička ekstruzija vrlo povoljna za dobijanje sferičnih čestica uskog opsega raspodele veličina koristeći nisko- i srednje-viskozne rastvore polimera (0,5, 1 i 2% alginata). Sa nisko-viskoznim rastvorom alginata, pod određenim uslovima, dobijene su čestice čiji je srednji prečnik čak manji i od 100 μn. Sa srednje viskoznim alginatnim rastvorom dobijene su čestice prečnika ispod 500 μm, koje su bile vrlo uniformne (srednje kvadratno odstupanje manje od 2,5%) i sferične (deformacija oblika manja od 1%), a smanjenjem protoka rastvora, moguće je dobiti čestice i manje od 300 μm. Poseban doprinos rada je u prevazilaženju ograničenja koja se odnose na ekstruziju veoma viskoznih rastvora. Optimizacija procesnih parametara koja je podrazumevala primenu vrlo tanke igle (0,15 mm), povećanje rastojanja između elektroda iznad 20 cm i smanjenje protoka ispod 5 ml/h (za 3% alginat), odn. 1 ml/h (za 4% alginat), omogućila je dobijanje malih, potpuno sferičnih i uniformnih mikročestica čiji je srednji prečnik bio ispod 500 i 700 μm za 3 i 4% alginatni rastvor, respektivno.",
publisher = "Savez hemijskih inženjera, Beograd",
journal = "Chemical Industry and Chemical Engineering Quarterly / CICEQ",
title = "Optimization of the electrostatic droplet generation process for controlled microbead production: Single nozzle system, Optimizacija elektrostatičkog generisanja čestica u cilju kontrolisanja njihovih mikronskih veličina - sistem sa jednom mlaznicom",
pages = "57-53",
number = "1",
volume = "12",
doi = "10.2298/CICEQ0601053N"
}

Nedović, V., Manojlović, V., Pruesse, U., Bugarski, B., Djonlagić, J.,& Vorlop, K. D.. (2006). Optimization of the electrostatic droplet generation process for controlled microbead production: Single nozzle system. in Chemical Industry and Chemical Engineering Quarterly / CICEQ
Savez hemijskih inženjera, Beograd., 12(1), 53-57.
https://doi.org/10.2298/CICEQ0601053N

Nedović V, Manojlović V, Pruesse U, Bugarski B, Djonlagić J, Vorlop KD. Optimization of the electrostatic droplet generation process for controlled microbead production: Single nozzle system. in Chemical Industry and Chemical Engineering Quarterly / CICEQ. 2006;12(1):53-57.
doi:10.2298/CICEQ0601053N .

Nedović, Viktor, Manojlović, Verica, Pruesse, Ulf, Bugarski, Branko, Djonlagić, Jasna, Vorlop, Klaus D., "Optimization of the electrostatic droplet generation process for controlled microbead production: Single nozzle system" in Chemical Industry and Chemical Engineering Quarterly / CICEQ, 12, no. 1 (2006):53-57,
https://doi.org/10.2298/CICEQ0601053N . .

TY  - JOUR
AU  - Manojlović, Verica
AU  - Djonlagić, Jasna
AU  - Obradović, Bojana
AU  - Nedović, Viktor
AU  - Bugarski, Branko
PY  - 2005
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/887
AB  - In this study, an attempt was made to assess the effects of cell addition and final concentration on the process of electrostatic extrusion as a method for cell immobilization in alginate microbeads. The electrostatic extrusion process is a complex function of several operating parameters, the system geometry, and the properties of the polymer solution, which is being extruded. The addition of cells results in the formation of a two-phase system, adding to the complexity of the process by the associated phenomenon of two-phase flow. This study especially focused on analyzing the effects of cell presence on each stage of the immobilization process. Specifically, the effects of the cell and alginate concentrations on the resulting microbead size and uniformity were assessed. Under the investigated conditions, microbeads, 50-600 ěm in diameter, were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with higher standard deviations in size. We attempted to rationalize the obtained findings by rheological characterization of the cell-alginate suspensions. H-NMR Spectroscopy of the alginate used in this study revealed a high content (67%) of guluronic residues and GG diad blocks (FGG = 55%). The mole fractions of the MM and GM diad sequences, Fmm and Fgm, were 21 and 12%, respectively. Rheological characterization revealed non-Newtonian, pseudoplastic behavior of the cell-alginate suspensions with an increase in viscosity as the alginate concentration was increased. However, the presence of cells even at high concentrations (5 ÷ 108 and 1 ÷ 109 cell/ml) did not significantly affect the rheological properties of Na alginate solution. Finally, the effects of the alginate and cell concentrations on the gelation kinetics and the dynamic-mechanical behavior of the obtained hydrogels were investigated. A molar ratio of G units to Ca2+ ions of 3.8 : 1 provided complete crosslinking, while an increase in the alginate concentration resulted in prolonged gelation times, but higher strength of the resulting gel. Cell presence decreased the rate of network formation, as well as the strength of the obtained Ca alginate hydrogel.
AB  - U ovom radu izvršeno je ispitivanje fenomena elektrostatičke ekstruzije. Proces elektrostatičke ekstruzije je vrlo složen, jer obuhvata pojedinačne uticaje različitih fenomenoloških parametara (jako spoljašnje električno polje, mikrohidrodinamičke pojave unutar kapilare, reološko ponašanje polimera), kao i međusobne uticaje ovih faktora. Prisustvo ćelija u sistemu čini ga još složenijim, što do sada fenomenološki nije razjašnjeno. Istraživanja su obuhvatila ispitivanje pojedinih značajnih fenomena koji se javljaju u ovoj metodi imobilizacije ćelija, polazeći od karakteristika samog nosača i suspenzije alginat/ćelije, preko parametara elektrostatičke ekstruzije, do kinetike geliranja alginata. Uz to, posebno je analiziran uticaj prisustva ćelija na sve faze ovog procesa. Detaljno je proučen uticaj promene koncentracije alginata i koncentracije ćelija u polaznoj suspenziji alginat/ćelije na veličinu i uniformnost proizvedenih mikročestica. Pri ispitivanim operativnim uslovima, proizvedene su mikročestice prečnika od 50-600 ěm i porast koncentracije bilo alginata, bilo ćelija uzrokuje nastajanje većih čestica neuniformnije raspodele veličina. U pokušaju da se objasne dobijeni rezultati i ispita reološko ponašanje suspenzije kao jedan od parametara koji utiču na dinamiku dvofaznog strujanja u toku ekstruzije, izvršeno je reološko karakterisanje suspenzija alginat/ćelije. Reološka ispitivanja su pokazala da prisustvo ćelija čak i pri visokim koncentracijama (5x108 i 1x10 ćelija/ml) ne utiče značajno na reološke osobine rastvora natrijum alginata. Na kraju, ispitan je uticaj koncentracije alginata i ćelija na kinetiku geliranja u uslovima ograničenog prisustva Ca jona, s obzirom da imobilizacija izuzetno osetljivih ćelija sisara može da zahteva minimalno izlaganje rastvoru CaCl2. Rezultati su pokazali da molski odnos guluronskih jedinica prema Ca2+ jonima od 3,8:1 omogućuje fizičko umrežavanje i da porast koncentracije alginata uzrokuje duže geliranje, ali i nastajanje jačeg gela. Prisustvo ćelija dovodi do sporijeg geliranja i prouzrokuje nastajanje slabijih hidrogelova što upućuje na zaključak da imobilisani mikroorganizmi uzrokuju nepravilnosti u strukturi mreže.
PB  - Savez hemijskih inženjera, Beograd
T2  - Chemical Industry and Chemical Engineering Quarterly / CICEQ
T1  - Effects of cell addition on immobilization by electrostatic droplet generation
T1  - Uticaj prisustva ćelija u procesu elektrostatičke ekstruzije alginata
EP  - 84
IS  - 2
SP  - 79
VL  - 11
DO  - 10.2298/CICEQ0502079M
ER  - 

@article{
author = "Manojlović, Verica and Djonlagić, Jasna and Obradović, Bojana and Nedović, Viktor and Bugarski, Branko",
year = "2005",
abstract = "In this study, an attempt was made to assess the effects of cell addition and final concentration on the process of electrostatic extrusion as a method for cell immobilization in alginate microbeads. The electrostatic extrusion process is a complex function of several operating parameters, the system geometry, and the properties of the polymer solution, which is being extruded. The addition of cells results in the formation of a two-phase system, adding to the complexity of the process by the associated phenomenon of two-phase flow. This study especially focused on analyzing the effects of cell presence on each stage of the immobilization process. Specifically, the effects of the cell and alginate concentrations on the resulting microbead size and uniformity were assessed. Under the investigated conditions, microbeads, 50-600 ěm in diameter, were produced and the increase in both alginate and cell concentrations resulted in larger microbeads with higher standard deviations in size. We attempted to rationalize the obtained findings by rheological characterization of the cell-alginate suspensions. H-NMR Spectroscopy of the alginate used in this study revealed a high content (67%) of guluronic residues and GG diad blocks (FGG = 55%). The mole fractions of the MM and GM diad sequences, Fmm and Fgm, were 21 and 12%, respectively. Rheological characterization revealed non-Newtonian, pseudoplastic behavior of the cell-alginate suspensions with an increase in viscosity as the alginate concentration was increased. However, the presence of cells even at high concentrations (5 ÷ 108 and 1 ÷ 109 cell/ml) did not significantly affect the rheological properties of Na alginate solution. Finally, the effects of the alginate and cell concentrations on the gelation kinetics and the dynamic-mechanical behavior of the obtained hydrogels were investigated. A molar ratio of G units to Ca2+ ions of 3.8 : 1 provided complete crosslinking, while an increase in the alginate concentration resulted in prolonged gelation times, but higher strength of the resulting gel. Cell presence decreased the rate of network formation, as well as the strength of the obtained Ca alginate hydrogel., U ovom radu izvršeno je ispitivanje fenomena elektrostatičke ekstruzije. Proces elektrostatičke ekstruzije je vrlo složen, jer obuhvata pojedinačne uticaje različitih fenomenoloških parametara (jako spoljašnje električno polje, mikrohidrodinamičke pojave unutar kapilare, reološko ponašanje polimera), kao i međusobne uticaje ovih faktora. Prisustvo ćelija u sistemu čini ga još složenijim, što do sada fenomenološki nije razjašnjeno. Istraživanja su obuhvatila ispitivanje pojedinih značajnih fenomena koji se javljaju u ovoj metodi imobilizacije ćelija, polazeći od karakteristika samog nosača i suspenzije alginat/ćelije, preko parametara elektrostatičke ekstruzije, do kinetike geliranja alginata. Uz to, posebno je analiziran uticaj prisustva ćelija na sve faze ovog procesa. Detaljno je proučen uticaj promene koncentracije alginata i koncentracije ćelija u polaznoj suspenziji alginat/ćelije na veličinu i uniformnost proizvedenih mikročestica. Pri ispitivanim operativnim uslovima, proizvedene su mikročestice prečnika od 50-600 ěm i porast koncentracije bilo alginata, bilo ćelija uzrokuje nastajanje većih čestica neuniformnije raspodele veličina. U pokušaju da se objasne dobijeni rezultati i ispita reološko ponašanje suspenzije kao jedan od parametara koji utiču na dinamiku dvofaznog strujanja u toku ekstruzije, izvršeno je reološko karakterisanje suspenzija alginat/ćelije. Reološka ispitivanja su pokazala da prisustvo ćelija čak i pri visokim koncentracijama (5x108 i 1x10 ćelija/ml) ne utiče značajno na reološke osobine rastvora natrijum alginata. Na kraju, ispitan je uticaj koncentracije alginata i ćelija na kinetiku geliranja u uslovima ograničenog prisustva Ca jona, s obzirom da imobilizacija izuzetno osetljivih ćelija sisara može da zahteva minimalno izlaganje rastvoru CaCl2. Rezultati su pokazali da molski odnos guluronskih jedinica prema Ca2+ jonima od 3,8:1 omogućuje fizičko umrežavanje i da porast koncentracije alginata uzrokuje duže geliranje, ali i nastajanje jačeg gela. Prisustvo ćelija dovodi do sporijeg geliranja i prouzrokuje nastajanje slabijih hidrogelova što upućuje na zaključak da imobilisani mikroorganizmi uzrokuju nepravilnosti u strukturi mreže.",
publisher = "Savez hemijskih inženjera, Beograd",
journal = "Chemical Industry and Chemical Engineering Quarterly / CICEQ",
title = "Effects of cell addition on immobilization by electrostatic droplet generation, Uticaj prisustva ćelija u procesu elektrostatičke ekstruzije alginata",
pages = "84-79",
number = "2",
volume = "11",
doi = "10.2298/CICEQ0502079M"
}

Manojlović, V., Djonlagić, J., Obradović, B., Nedović, V.,& Bugarski, B.. (2005). Effects of cell addition on immobilization by electrostatic droplet generation. in Chemical Industry and Chemical Engineering Quarterly / CICEQ
Savez hemijskih inženjera, Beograd., 11(2), 79-84.
https://doi.org/10.2298/CICEQ0502079M

Manojlović V, Djonlagić J, Obradović B, Nedović V, Bugarski B. Effects of cell addition on immobilization by electrostatic droplet generation. in Chemical Industry and Chemical Engineering Quarterly / CICEQ. 2005;11(2):79-84.
doi:10.2298/CICEQ0502079M .

Manojlović, Verica, Djonlagić, Jasna, Obradović, Bojana, Nedović, Viktor, Bugarski, Branko, "Effects of cell addition on immobilization by electrostatic droplet generation" in Chemical Industry and Chemical Engineering Quarterly / CICEQ, 11, no. 2 (2005):79-84,
https://doi.org/10.2298/CICEQ0502079M . .